Efficient Brushless DC Motor

[wright100]

Hey,

This is not exactly for a airplane or anything like that, but rather is for a different project I am working for. I havn't done that much work with RC Electric motors, so I was wondering if people who have been working with this stuff way longer than I have could point me toward the most efficient motor for a airplane or boat type application. I am working on a school project called SuperMileage where we build extremely high mileage vehicles and compete for the best mileage. I am working on a hybrid design and believe it or not (I don't sometimes) a little electric RC motor is what we need to drive this car. They difficulty however, is getting one that is as efficient as possible.

Does anyone know of modifications that can be made to these motors to make them more efficient as well? Thanks for any help guys.

Nate

[Beaverdam]

Brushless inrunners are generally the most efficient, but difficult to modify. Try http://www.neumotors.com/Site/Motors.html

[wright100]

Thanks. I just checked those out. I'm going to call the company tomorrow to get some more information. Bu they definately look like they will fit my application. Are there any other brands people recommend? I looked into Hacker and am planning on calling them too.

Nate

[vintage1]

be aware that senorsless brushless motors have very poor starting torque and would need a clutch for use in a car.

[Fourdan]

Hi
Be aware also of the Kv value to be able to make the reducer ratio by a chain or a belt.
The lower the Kv, the lower the motor rpm, and motor pinion is more confortable.
Look at this forum
http://www.endless-sphere.com/forums/viewtopic.php?f=28&t=9061

Louis

[Ron van Sommeren]

Maybe try Georges van Ganssen at www.scorpionsystem.com (http://www.scorpionsystem.com) for a 'special' Louis?
E.g. via
http://www.rcgroups.com/forums/showthread.php?t=660918

Vriendelijke groeten ;) Ron

[BobDiode]

Hey,

This is not exactly for a airplane or anything like that, but rather is for a different project I am working for. I havn't done that much work with RC Electric motors, so I was wondering if people who have been working with this stuff way longer than I have could point me toward the most efficient motor for a airplane or boat type application. I am working on a school project called SuperMileage where we build extremely high mileage vehicles and compete for the best mileage. I am working on a hybrid design and believe it or not (I don't sometimes) a little electric RC motor is what we need to drive this car. They difficulty however, is getting one that is as efficient as possible.

Does anyone know of modifications that can be made to these motors to make them more efficient as well? Thanks for any help guys.

Nate
What kind of gross vehicle weight are you talking?

[Fourdan]

Hey,

This is not exactly for a airplane or anything like that, but rather is for a different project I am working for. I havn't done that much work with RC Electric motors, so I was wondering if people who have been working with this stuff way longer than I have could point me toward the most efficient motor for a airplane or boat type application. I am working on a school project called SuperMileage where we build extremely high mileage vehicles and compete for the best mileage. I am working on a hybrid design and believe it or not (I don't sometimes) a little electric RC motor is what we need to drive this car. They difficulty however, is getting one that is as efficient as possible.

Does anyone know of modifications that can be made to these motors to make them more efficient as well? Thanks for any help guys.

Nate
Hi
Is it a similar challenge to Ford Electrathon Nissan race ?
Louis

[BobDiode]

Hi
Is it a similar challenge to Ford Electrathon Nissan race ?
Louis

With a 10 pound PM alternator with hall sensors and a great efficiency using a 14 pole 4" rotor you can have a direct chain drive using 1 hp to 16 HORSEPOWER! Not too shaby for a motor you can get for under $200. The voltage/RPM and torque can be adjusted by a slection of 6 stator windings available.
A one of a kind Motor (http://www.rcgroups.com/forums/showthread.php?t=905411&page=13)

[rich smith]

The use of a gearbox provides much better efficiency in most applications compared to any issues regarding type of motor.

[wright100]

Thanks for the big response guys. The vehicle weights is approximately 350 lbs. However, the car is extremely streamlined with very low rolling resistance. With a 50cc engine we were getting about 1000 miles per galon. The race seems similar to the one someone mentioned by Ford, except these are mainly gas engines instead of electric. The cars look identical to ours actually so I'd say its very similar. The other difference is that its mainly gas engines our team will probably be the only one employing electric power. We want to use an electric engine that is powered by a generator connected to the gas engine. By doing this we can optomize the gas engine to a single RPM and use regenerative braking to reduce loses due to traveling at speeds higher than necessary.

By going this route we add more components to the system which induces greater loss so we are trying to optomize the efficiency of our electric drivetrain so we don't eat up our gains by decreasing efficiency.

Someone mentioned using a gearbox. Wouldn't adding a gearbox decrease the efficiency because there will be losses associated with it? The advantage I could see to going that route is that it may allow us to run the electric motor where it is most efficient.

Probably a dumb question but what is a 'special' Louis?

Nate

[rich smith]

Do you have any more info or links. I use a 50cc for main tranportation and would love to increase mileage to 1000 from my current 210. :)

I remember wrapping moped cyclinders in fiberglass insulation to get up there but not up to date on current state of the art.

[BobDiode]

Thanks for the big response guys. The vehicle weights is approximately 350 lbs. However, the car is extremely streamlined with very low rolling resistance. With a 50cc engine we were getting about 1000 miles per galon. The race seems similar to the one someone mentioned by Ford, except these are mainly gas engines instead of electric. The cars look identical to ours actually so I'd say its very similar. The other difference is that its mainly gas engines our team will probably be the only one employing electric power. We want to use an electric engine that is powered by a generator connected to the gas engine. By doing this we can optomize the gas engine to a single RPM and use regenerative braking to reduce loses due to traveling at speeds higher than necessary.

By going this route we add more components to the system which induces greater loss so we are trying to optomize the efficiency of our electric drivetrain so we don't eat up our gains by decreasing efficiency.

Someone mentioned using a gearbox. Wouldn't adding a gearbox decrease the efficiency because there will be losses associated with it? The advantage I could see to going that route is that it may allow us to run the electric motor where it is most efficient.

Probably a dumb question but what is a 'special' Louis?

Nate
Knowing all the details will help. What kind of hills ? how steep and long ? At what average speed? What are the wind conditions ? How many watt hours of batteries can you take and what chemistry of batteries are allowed ? It sounds like you need a vary efficient 200 watt to 2 Hp electric motor. A #219 or 8 mm gokart roller chain with about a 8 to 1 ratio with a composite sprocket on the wheel with Sram Dual Drive 3 speed hub with slow moving planetary gears in the hub that freewheels while coasting incorperated with a Robins 50 cc motor and the efficient PM alternator motor to drive the wheel directly. I would NOT put regen on it because you will have a better advantage coasting freely.
Another option would be to use the PM motor to always drive the wheel by batteries and when your battery power runs out have the Robbins 50cc motor coupled to a different PM alternator with a non cogging 7 pole rotor Salant Core 7 pole rotor design for under $200. that you just missed on this Ebay auction.
http://cgi.ebay.com/SCS-PMA-12-24-48-V-Wind-Turbine-Alternator-Generator_W0QQitemZ300343281667QQcmdZViewItemQQptZ LH_DefaultDomain_0?hash=item45eddac803&_trksid=p3286.c0.m14
On both the motor or alternator you can adjust your Voltage/RPM = KV or torque= KT by your slection of 6 stator windings to meet your needs.
http://www.hydrogenappliances.com/pmaparts.html
http://www.hydrogenappliances.com/pmacurves.html
http://www.hydrogenappliances.com/powerpmas.html

[Jeffery]

There's a competition in Europe along similar lines, here's a link (it's in German, but you can understand enough to Google your way to more info) to a scooter that won the 2006 competition at 94% efficiency, and it had chain reduction of a sensorless, brushless, inrunner.

http://www.lehner-motoren.com/download/ziegler.pdf

[BobDiode]

There's a competition in Europe along similar lines, here's a link (it's in German, but you can understand enough to Google your way to more info) to a scooter that won the 2006 competition at 94% efficiency, and it had chain reduction of a sensorless, brushless, inrunner.

http://www.lehner-motoren.com/download/ziegler.pdf

With a alternator Motor I put together I climbed this 10,005 ft Volcano in 3 hours in 2003 with non Lithium batteries with a gross weight of 310 lbs.
Full Suspension Huffy with a 5 lb Ford Alternator/Motor with a 12 pole PM Rotor
94% Efficient up to 1600 watts


Worlds Record Climbing 10,005 ft On A Electric Bike With A 5 Pound Alternator Motor (http://evworld.com/article.cfm?storyid=562)

http://www.youtube.com/watch?v=4srFXaXpZEI

0 to 24 MPH Pedaling Through 3 Gears (http://www.youtube.com/watch?v=CHgmQ-80elk)

http://www.rcgroups.com/forums/showthread.php?t=905411&page=13

[wright100]

Here are some links if people are interested:

My School's SuperMileage team page:
http://cusupermileage.blogspot.com/

Shell Eco Marathon(This is the one with the Europe Division)... They dominate the U.S. every year I believe.
http://www.shell.com/home/content/ec...me_global.html

SAE SuperMileage
http://students.sae.org/competitions/supermileage/

*************************************************

The hills aren't incredibly steep. There is a 1-2% grade for a pretty long time though. Maybe half a mile... I am not a driver and they don't let us walk the track, so my knowledge is mainly from Google Earth lol. The downhill is much steeper. In previous races the car will go from about 2mph to 30 mph. Here is a quick overview of what the race is:

Basically they give you a set amount of gasoline and put you out on the track. You are required to complete X number of laps (differs by competition) in Y minutes. What it comes down to is if you need to average 15MPH over the entire race. When you come in they check how much gas you have used and calculate your MPG.

Wind conditions vary by location. Last year we were at the California Speedway and it could gust up to like 30 MPH. In Michigan at the Eaton Proving Grounds it would be like 10 MPH. Nothing bad. This year we are in Houston which isn't extremely windy and Michigan again.

There isn't a limit to the number of batteries, however we have to prove to the judges that they are dead before the race. Right now we are planning on using ultra-capacitors because they are highly efficient and can handle large amounts of current.


Right now our reasoning behind regen is that >70% of our losses are from air resistance. The rolling resistance accounts for the rest. This isn't including stuff like heat from the engine etc. The power lost due to the drag on the car is a function of V^3. So if we can efficiently hold the car at 15 MPH while efficiently recovering the power from the braking, we could charge our ultra-capacitors and use it to climp the next hill instead of having to run the gas motor to generate more electricity.

Bob - Did you make modifications to that motor to get that kind of efficiency out of it?


Jeffery - Thankyou for that link. I'm going to try and find an English version to read. I heard at the competition about this team, but never heard many specifics.

[BobDiode]

Here are some links if people are interested:

My School's SuperMileage team page:
http://cusupermileage.blogspot.com/

Shell Eco Marathon(This is the one with the Europe Division)... They dominate the U.S. every year I believe.
http://www.shell.com/home/content/ec...me_global.html

SAE SuperMileage
http://students.sae.org/competitions/supermileage/

*************************************************

The hills aren't incredibly steep. There is a 1-2% grade for a pretty long time though. Maybe half a mile... I am not a driver and they don't let us walk the track, so my knowledge is mainly from Google Earth lol. The downhill is much steeper. In previous races the car will go from about 2mph to 30 mph. Here is a quick overview of what the race is:

Basically they give you a set amount of gasoline and put you out on the track. You are required to complete X number of laps (differs by competition) in Y minutes. What it comes down to is if you need to average 15MPH over the entire race. When you come in they check how much gas you have used and calculate your MPG.

Wind conditions vary by location. Last year we were at the California Speedway and it could gust up to like 30 MPH. In Michigan at the Eaton Proving Grounds it would be like 10 MPH. Nothing bad. This year we are in Houston which isn't extremely windy and Michigan again.

There isn't a limit to the number of batteries, however we have to prove to the judges that they are dead before the race. Right now we are planning on using ultra-capacitors because they are highly efficient and can handle large amounts of current.


Right now our reasoning behind regen is that >70% of our losses are from air resistance. The rolling resistance accounts for the rest. This isn't including stuff like heat from the engine etc. The power lost due to the drag on the car is a function of V^3. So if we can efficiently hold the car at 15 MPH while efficiently recovering the power from the braking, we could charge our ultra-capacitors and use it to climp the next hill instead of having to run the gas motor to generate more electricity.

Bob - Did you make modifications to that motor to get that kind of efficiency out of it?


Jeffery - Thankyou for that link. I'm going to try and find an English version to read. I heard at the competition about this team, but never heard many specifics.
I can tell you for sure that freewheel coasting does a lot better than any regen can do. On my small PM motor the rotor was the only item that was made with small but strong magnets. On the rotors in the PM alternators the magnets are much stronger and about 10 times the size!
At 1300 watts max I took this 30% grade. My overall drive train efficiency is about 90% and you should get a hair better with the SC 24 stator PM alternators on Ebay at 48 volts. You might also get the SC 18 stator to try with a higher rpm or lower voltage. At 10 mph you should get about 10 to 15 watt hours per mile depending on your gross weight. Hills will not effect this on a round trip. A head wind will unless you have the same conditions on a round trip.
http://www.youtube.com/watch?v=XcXmOa2N1x0

[Ron van Sommeren]

Slotless motors (e.g. Kontronik Tango, Lehner?, Hacker?) have highest efficiency but they need gearing (and litze wire).

If you want to make your own slotless motor, notably Thomas Asschenbrenners site:
http://www.rcgroups.com/forums/showthread.php?t=473418

Other method for making slotless coils:
http://www.electrifly.com/motors/gpmg5000.html

Vriendelijke groeten ;) Ron

[BobDiode]

Slotless motors (e.g. Kontronik Tango, Lehner?, Hacker?) have highest efficiency but they need gearing (and litze wire).

If you want to make your own slotless motor, notably Thomas Asschenbrenners site:
http://www.rcgroups.com/forums/showthread.php?t=473418

Other method for making slotless coils:
http://www.electrifly.com/motors/gpmg5000.html

Vriendelijke groeten ;) Ron

Gearing a tiny RC motor to get any torque for a 300 lb vehicle will need to be mulitpul reductions with many friction losses in the area of 20%.
It's better to use a 2500 rpm motor with enough torque with a single chain reduction for the best overall efficiency.

[rich smith]

I can tell you for sure that freewheel coasting does a lot better than any regen can do.

Maybe on some concept vehicle w/o brakes. In the real world with stop lights and pedestrians recovery of battery energy can be helpful.

[gkamysz]

Most of these mileage competitions do not include braking, unless you need to to stay within the speed limit. Shell has an urban event that includes stop and go.

[wright100]

I think we will probably design for regen, but ditch the idea if our tests show that we can do better with just free wheeling. I think a lot of it will depend on how efficient we can get the regen to be. If we are throwing away a lot of power on the regen then it won't be worth it.

[Ron van Sommeren]

Gearing a tiny RC motor to get any torque for a 300 lb vehicle will need to be mulitpul reductions with many friction losses in the area of 20%. ...Don't worry, I was not thinking of tiny slotless motors. Hence the diy links I gave.

Vriendelijke groeten ;) Ron

[Ron van Sommeren]

This e-bike project used www.torcman.de (http://www.torcman.de/index_e.htm) motors, 150km/kWh:
http://www.sinusleistungssteller.de/QUEST.html
More about these non-trapezoidal sinusoidal controllers, user RogerZ is one of the developers:
http://www.rcgroups.com/forums/showthread.php?t=788065

Use http://translate.google.com/ for automatic translation. Far from perfect but good enough for context-restricted-techno-geek-speak :D

berg ab = downhill
berg auf = uphill
Test eines Velomobils mit Elektro-Hilfsantrieb (http://www.youtube.com/watch?v=jalqEEZVs0c) (10 min 3 sec)
(10 min 3 sec)
(10 min 3 sec)
(10 min 3 sec)

[Fourdan]

Hi

Quest performance 150km/kWh is "only" 6.667 Wh/km
In 2009 there was a french challenge EducEco
(on Grand-prix ring Nogaro)
Range 7 laps = 25.372 km to run at least 30 km/h average speed
We (I collaborate to ParisX University IUT-VA for motoring) won
"all electric" category with 1.458 Wh per km
Look at http://www.educeco.com
Measurements made with "Joulemeters" provided and tested by the official organizer's engineers.

Louis

[wright100]

Fourdan--How big of a motor did you use to travel at that speed?

[BobDiode]

Fourdan--How big of a motor did you use to travel at that speed?

If your race is long distance relying on gas fuel for power you would be best off using a efficient gas engine with no electric motor. Even with a efficient Honda generator your electrical conversion losses to the motor would be about 20%. To store energy in a battery by generating it on the fly would be even worse unless you can not optimise the gas engine gearing for direct drive through efficient gearing?

http://honda.northerntool.com/generators/honda-eu1000ian.htm
http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_297_297
http://www.staton-inc.com/Results1.asp?Category=13

HyBrid Electric and Gas Staton Gear and Chain Drive Component System
http://www.staton-inc.com/Details.asp?ProductID=3319

25.372 km = 15.77 miles = @ 36.992 watt hours =2.345 wh per mile @ 18.64 mph must be a flat track with no wind and a vary light gross weight with a good air foil. It surly did not need but a 1 pound pack of batteries

[Fourdan]

Hi Wright100
Just a stock Dualsky XM6360CA-12
weight 618g
Kv measured 220 rpm/V
Look at Dualsky website, there is a little word about Nogaro EducEco2009
+ pictures
Louis

[lutach]

You could try a wheel/hub type motor in the 200-500W range. One in each wheel will be enough to move the car. Some have shown to be very efficient. Use solar panels in conjunction with any allowable batteries and that should get the job done. Maybe add 2 other power sources such as air and hydraulic.

[BobDiode]

I can tell you for sure that freewheel coasting does a lot better than any regen can do. On my small PM motor the rotor was the only item that was made with small but strong magnets. On the rotors in the PM alternators the magnets are much stronger and about 10 times the size!
At 1300 watts max I took this 30% grade. My overall drive train efficiency is about 90% and you should get a hair better with the SC 24 stator PM alternators on Ebay at 48 volts. You might also get the SC 18 stator to try with a higher rpm or lower voltage. At 10 mph you should get about 10 to 15 watt hours per mile depending on your gross weight. Hills will not effect this on a round trip. A head wind will unless you have the same conditions on a round trip.
http://www.youtube.com/watch?v=XcXmOa2N1x0
If you understand how the Chevy Volt is getting such a high MPG rating you will see that any regen will cost you to charge the dead batteries up.
General Motors believes that although the Volt is an entirely new type of vehicle, it suggests that altering the current EPA hybrid testing methods to suit a single vehicle entry would be unfair and would not recognize the fact that the car can travel an estimated 40 miles (64 km) on battery power alone before the gasoline powered engine has to be started to commence recharging its battery pack. The Volt only gets about 48 mpg when charged "free 40 miles" ARE added into the EPA figures. http://blogs.motortrend.com/6293345/government/could-the-epa-cripple-the-chevy-volt/index.html
A 1980 VW Rabbit diesel pick up truck I had for 500,000 miles of use averaged over 53 mpg.
If your dead batteries or capacitors need to be charged up to use a electric motor you will be carrying all that extra weight. On the down hill legs of the course regen will only slow down your free speed over distance and will not re generate unless you buck boost the voltage up or have gearing to spin your motor faster than it will operate at full freespin rpm. A heavy car can do this for semi fast stops and long down hill runs.. A lightweight racer will just stop! Now if you run a 29 pound 1kw Honda generator constantly to charge your batteries up from a dead condition and to maintain a 15 to 18 mph speed you will need to do some distance tests to see when your gas runs out and how many watt hours or capacity your batteries have from the charging and how long they will last at the same speeds to climb hills or what ever conditions you encounter for the reminder of your trip. IMO a small efficient diesel generator will give you more torque at a better efficiency at a lower rpm for less reduction losses and a better over all efficiency. It may be better to use only a efficient engine and ditch the electrical and weight losses. This is what will need to be tested in real world results with a efficient streamlined vehicle with no speed limits on coasting. If regen was decided on you would have to figure on running the engine constantly or figure out when and how to start the engine up for the most efficient way to use it in combination with the motor/ alternator and batteries. I am sure you have thought about all of this. Now if you had a efficient light weight fuel cell reformer you would be in business! :)
To keep up to date these races need to allow the use of hydrogen fuel. But I inmaine there are politics involved.
http://www.fuelcellstore.com/en/pc/viewPrd.asp?idcategory=53&idproduct=1450#details
http://www.fuelcellstore.com/en/pc/viewPrd.asp?idcategory=53&idproduct=1450

[jmygann]

so I am thinking a quad cycle with SRAM 3 speed and PM alternator

http://www.utahtrikes.com/uploads/uttrikes/20/picture5/quadrear.jpg

http://www.utahtrikes.com/TRIKE-UTCQUAD.html

[BobDiode]

so I am thinking a quad cycle with SRAM 3 speed and PM alternator

http://www.utahtrikes.com/uploads/uttrikes/20/picture5/quadrear.jpg

http://www.utahtrikes.com/TRIKE-UTCQUAD.html
You can use the PM alternator/ Motor for a single chain reduction to a axle freewheel like a gokart is set up and will have plenty of efficient torque without multipul gears for the motor and drive your pedals however you like. :)

[jmygann]

But don't I want to run the motor thru the SRAM ?

[Christian Lucas]

Hi,
for best milage you need a fuelcell and a symply Maxonmotor as the world efficancy car the Paccar use at the Shell Kilometermaraton.Fuelcell with 1000 watt peak power run under load at 30 km/h with only 15-20 watt .This give the higest efficancy as the fuelcell run with 15 watt like freerunning and so it can run at highest volt.See efficancy of a fuelcell is related to the load volts.Max power at halve volts of the freeruning volts.Freeruning volts are 1,24 volt and at 0,62 volt you have the max power and an efficancy of 50% running with less load will rise dropp down the volts less and efficancy will be high.

If you run a brushless motor think about a sensor ,as otherwise you will get problems during start.
At the Michelin Bibendum Race hold in Paris a German team won woth a two wheel motorisised bike powered by an Lehner Motor with gear.Manytest ofthe Univercity show highes efficancy with this drive combination , http://www.lehner-motoren.de/download/ziegler.pdf .

http://www.paccar.ethz.ch/index_DE .

[BobDiode]

Hi,
for best milage you need a fuelcell and a symply Maxonmotor as the world efficancy car the Paccar use at the Shell Kilometermaraton.Fuelcell with 1000 watt peak power run under load at 30 km/h with only 15-20 watt .This give the higest efficancy as the fuelcell run with 15 watt like freerunning and so it can run at highest volt.See efficancy of a fuelcell is related to the load volts.Max power at halve volts of the freeruning volts.Freeruning volts are 1,24 volt and at 0,62 volt you have the max power and an efficancy of 50% running with less load will rise dropp down the volts less and efficancy will be high.

If you run a brushless motor think about a sensor ,as otherwise you will get problems during start.
At the Michelin Bibendum Race hold in Paris a German team won woth a two wheel motorisised bike powered by an Lehner Motor with gear.Manytest ofthe Univercity show highes efficancy with this drive combination , http://www.lehner-motoren.de/download/ziegler.pdf .

http://www.paccar.ethz.ch/index_DE .

Small efficient high Rpm motors may be fine in a lightweight race car on ideal tracks and conditions. In real life conditions that include 300 pound payloads, steep hills and 30 mph headwinds a single chain reduction to a larger 1000 watt motor with plenty of efficient torque will endure for 1000s of hours at a better efficiency in all conditions. A light RC motor set up may be good for a 1 hour flat track race in a light vehicle in ideal conditions but that's about it.
A quality sensorless controller will work great at 1 rpm on, when using a larger motor at 10 watts or 1000 watts. The weight savings using a rc Motor and gear reduction (compared to a 10 pound motor that is just as efficient under any load) is what ? Now talk about cost benifet and life expectency.

[BobDiode]

But don't I want to run the motor thru the SRAM ?
Only if you want to keep the voltage down below 36 volts and have a higher shiftable gear for a faster speed than 30 mph. You may find that a SC 18 or SC 24 stator may even have a high enough rpm to go faster than 30 mph and have enough touque for hills if geard properly with a single ratio.Adding more voltage will increase your RPM band the same way as a stator with thicker wire and less turns. You can even use a stock 12 volt Delco stator for the highest RPM but less torque inless you geard lower. To find what works best for you it is easy to change sprockets, Voltage, or stators when you have a slection of six stators to choose from using from 12 volts to 1200 volts. Not many motors have these options.
http://www.hydrogenappliances.com/pmacurves.html

[jmygann]

Okay ... if running 48 volts on a rear drive as shown above , better to just mate the PM motor to the rear drive shaft .. correct

the problem with a quad is that is not a "bicycle" in many jurisdictions ...

so I am thinking a trike .. maybe like this with center drive assist

http://www.youtube.com/watch?v=PJJLhDlxBss

[wright100]

For us fuel cells are not really an option. There are fuel cell cars at competition, however they are in a different group than we are. The hybrid would still be considered part of the combustion engine group because all of the energy comes from the ICE.

For regen, I do not know for sure if whether it is better to just coast down the hills or to regen and hold ourselves at a fixed speed. It is difficult to know what is better until we can determine what the efficiency of the regen would be. Regen would be better if the energy gained after losses by regen is greater than the increase in drag on the car caused by traveling at twice the normal speed. I can say for certain that regen would be the correct way to go if the regen was 100% efficient because loses due to drag do significantly increase with speed. Clearly we won't be regening at 100% though.

Right now we think the greatest benefit of the hybrid drivetrain is the fact that we can then run the ICE engine at a constant RPM. This should increase our efficiency immensely.

Right now for regen we are not necessarily thinking about buying a generator. Could we not just buy a medium sized efficient electric engine to act as a generator? Clearly it would be more complicated than that, but I don't think we necessarily have to use a large generator.

Nate

[BobDiode]

For us fuel cells are not really an option. There are fuel cell cars at competition, however they are in a different group than we are. The hybrid would still be considered part of the combustion engine group because all of the energy comes from the ICE.

For regen, I do not know for sure if whether it is better to just coast down the hills or to regen and hold ourselves at a fixed speed. It is difficult to know what is better until we can determine what the efficiency of the regen would be. Regen would be better if the energy gained after losses by regen is greater than the increase in drag on the car caused by traveling at twice the normal speed. I can say for certain that regen would be the correct way to go if the regen was 100% efficient because loses due to drag do significantly increase with speed. Clearly we won't be regening at 100% though.

Right now we think the greatest benefit of the hybrid drivetrain is the fact that we can then run the ICE engine at a constant RPM. This should increase our efficiency immensely.

Right now for regen we are not necessarily thinking about buying a generator. Could we not just buy a medium sized efficient electric engine to act as a generator? Clearly it would be more complicated than that, but I don't think we necessarily have to use a large generator.

Nate

Hi Nate,
What I think you are missing is that regen will only be effective is when your alternator or generator is spinning past the rpm of what it would run as a motor. If you had a small 12 volt motor with a low rpm and used it to with a hard roller to spin against the outside diameter of your tire via a cable to a hand lever and a spring to hold it down when you start going over 18 mph to charge and give braking action you will get some regen action depending on the voltage of your batteries, There will be a elcetrical loss if 10% from generator plus a battery conversion loss of 10% depending on your batteries used then another loss of at least 10% to run a efficient motor to use the power plus drive friction losses. That is only if you set the system up for optimal use while loosing speed and carrying extra weight.
It would stand to reason that you can use the coasting effect to increase your speed and distance without slowing down. To use a gas engine more efficiently and keep it it's optpimal RPM on up hill or on the down hill sections
a efficient through the hub bicycle multipul speed hub would do the job if you first had a efficient primary engine reduction such as a gokart chain and sprocket set up and forget the electrical system.
A gas 50cc engine geard right will be more effective than adding electric IMO.

Up to 160 mpg and 30 to 40 mph speeds.

http://www.thatsdax.com/

[BobDiode]

Okay ... if running 48 volts on a rear drive as shown above , better to just mate the PM motor to the rear drive shaft .. correct

the problem with a quad is that is not a "bicycle" in many jurisdictions ...

so I am thinking a trike .. maybe like this with center drive assist

http://www.youtube.com/watch?v=PJJLhDlxBss

I would start with a freewheel and a 90 tooth #219 chain sprocket on the wheel hub or wheel axial if it will fit. I do not see any other place except on the wheel where the sprocket will fit. You can possibly run a 2 to 1 one reduction to the motor on the empty sprocket in the picture if you used a SC 48 or SC 60 Stator for a higher torque and lower RPM motor. When more people start using these PM alternator/ motors with all the different stators we will get a better idea of the gearing, RPM and torque options for each stator.
My guess would be using the high torque SC 60 stator with a 2 to 1 reduction at 36 volts you would be spinning the wheel 234 rpm and at 48 volts it will spin the wheel at 312 rpm.
the SC 48 = 357 wheel RPM at 36 volts and 476 RPM at 48 volts with 2 to 1 reduction. To caculate your speed you need to do the math with your wheel size.
You could probably pick up the stator you want for under $20.00 if you win the bid. Personaly I would take the SC 24 stator with the large sprocket aproach.
http://cgi.ebay.com/COIL-of-Wind-Turbine-PMA-Permanent-Alternator-Generator_W0QQitemZ280395934817QQcmdZViewItemQQptZ LH_DefaultDomain_0?hash=item4148e66c61&_trksid=p3911.c0.m14
http://www.fastech-racing.com/product.php?printable=Y&productid=272&cat=113&page=1&js=n

[jmygann]

what is the difference between the quad core and the super core ?

[BobDiode]

what is the difference between the quad core and the super core ?

The Quad Core relates to the #12 stator. Super Core relates to the Rotor with 14 magnets.

My guess is since the stock 12 Volt Delco stator has the thickest wire and the least windings. They may have added more copper by running 4 strands of thinner wire 1/4 the size in parallel to put more windings of copper on the stator to increase the amperage with less resistance. It would spin much too fast to be used as a motor unless you used it at 12 volts at a high amperage and rpm. But again that is only a guess.
You can pick up a standard 12 volt stator on ebay for $27.00 or for less at any junk yard.

[BobDiode]

Hey,

This is not exactly for a airplane or anything like that, but rather is for a different project I am working for. I havn't done that much work with RC Electric motors, so I was wondering if people who have been working with this stuff way longer than I have could point me toward the most efficient motor for a airplane or boat type application. I am working on a school project called SuperMileage where we build extremely high mileage vehicles and compete for the best mileage. I am working on a hybrid design and believe it or not (I don't sometimes) a little electric RC motor is what we need to drive this car. They difficulty however, is getting one that is as efficient as possible.

Does anyone know of modifications that can be made to these motors to make them more efficient as well? Thanks for any help guys.

Nate

A larger motor built like a RC motor will have much more torque without needing such a large reduction and will be much more efficient for real world conditions such as hills, headwinds and payloads. Also a Gaint RC project using a huge direct drive prop at 16000 rpm up to 6.7 Kw of power with a Castle Creations HV-140 Amp controller.

[wright100]

Hi Nate,
What I think you are missing is that regen will only be effective is when your alternator or generator is spinning past the rpm of what it would run as a motor. If you had a small 12 volt motor with a low rpm and used it to with a hard roller to spin against the outside diameter of your tire via a cable to a hand lever and a spring to hold it down when you start going over 18 mph to charge and give braking action you will get some regen action depending on the voltage of your batteries, There will be a elcetrical loss if 10% from generator plus a battery conversion loss of 10% depending on your batteries used then another loss of at least 10% to run a efficient motor to use the power plus drive friction losses. That is only if you set the system up for optimal use while loosing speed and carrying extra weight.
It would stand to reason that you can use the coasting effect to increase your speed and distance without slowing down. To use a gas engine more efficiently and keep it it's optpimal RPM on up hill or on the down hill sections
a efficient through the hub bicycle multipul speed hub would do the job if you first had a efficient primary engine reduction such as a gokart chain and sprocket set up and forget the electrical system.
A gas 50cc engine geard right will be more effective than adding electric IMO.

Up to 160 mpg and 30 to 40 mph speeds.

http://www.thatsdax.com/


I don't think the conversion is going to be all that bad. 10% losses seem high for the regen generator. Because we are most likely going to be using ultra-capacitors as our storage device which are 98-99% efficient I expect the regen efficiency to be somewhere in the lower 80's.

I don't entirely understand what you are saying regarding the regen. Most likely due to my lack of knowledge on the subject. It is on my long list of things to research. Time is always the most constrained resource... As for our project, it is defined as designing a hybrid electric system for the car. We cannot stop this project and move to a purely mechanical solution because the team is composed of electrical engineers and computer engineers. The project has to fall into the realm of our discipline. So we have no choice but to move forward with the hybrid design and create the most effective system we can.

What I am thinking is we could possibly create a parallel system where the ICE engine is run on the uphill segments of the course. It would allow us to bypass the inefficiency of the system and power the wheel directly as long as we can continue to run the engine at its optimal RPM. This would be during the largest power drain on the system. Coming down the hill we can use regen to hold the speed at 15 MPH and fill the capacitors. This power would then be used on the relatively flat segments of the track to hold the car at 15 MPH. This system seems efficient as long as regen really provides an advantage and as long as we are capable of of keeping the ICE engine at a constant RPM.

Nate

[BobDiode]

I don't think the conversion is going to be all that bad. 10% losses seem high for the regen generator. Because we are most likely going to be using ultra-capacitors as our storage device which are 98-99% efficient I expect the regen efficiency to be somewhere in the lower 80's.

I don't entirely understand what you are saying regarding the regen. Most likely due to my lack of knowledge on the subject. It is on my long list of things to research. Time is always the most constrained resource... As for our project, it is defined as designing a hybrid electric system for the car. We cannot stop this project and move to a purely mechanical solution because the team is composed of electrical engineers and computer engineers. The project has to fall into the realm of our discipline. So we have no choice but to move forward with the hybrid design and create the most effective system we can.

What I am thinking is we could possibly create a parallel system where the ICE engine is run on the uphill segments of the course. It would allow us to bypass the inefficiency of the system and power the wheel directly as long as we can continue to run the engine at its optimal RPM. This would be during the largest power drain on the system. Coming down the hill we can use regen to hold the speed at 15 MPH and fill the capacitors. This power would then be used on the relatively flat segments of the track to hold the car at 15 MPH. This system seems efficient as long as regen really provides an advantage and as long as we are capable of of keeping the ICE engine at a constant RPM.

Nate
OK I did not understand that you have to use a Hybrid system. Again, You must not understand the the electrical/ mechanical losses for a generator or alternator that are about 10% using a efficient system. Say you have a highly efficient motor or generator of 93 or 94% you can't get any better off the shelf that is cost effective. Most Field wound rotor car alternators on automobiles are under 60% efficient if that, then another 20% electrical conversion loss to charge the lead acid batteries. As you say Caps or Lithium batteries may take a couple %. So you end up with a 90% overall efficiency or less just on direct charging if you are lucky. OK, now you have some stored energy and the gen set is still running and you have a highly efficient electric motor of 94% efficiency. Depending on your reduction losses you need to add in will range from 2% to 4% on a single chain reduction. Any hard gear reductions including planetary gears or belts are only about 80% efficient for each stage of reduction unless you pay about $1000. For the best planetary gear box you can get which is 85% efficient per stage up to a 10 to 1 reduction and with a 5000 rpm limit. Add all this up and if you are running within the optimal load, RPM, vehicle speed and wattage zones that is what your losses will be. In most cases smaller is not more efficient in the long run. eliminating high rpm losses that are associated with high rpm motor and reduction friction losses is important and having a broad sweet spot will work best on hills and a variable speed.
To get a real regen from wheels and motor/alternator either you have to be spinning the motor faster than your batteries voltage will make the motor freespin without a load, say 2000 rpm at 48 volts. After 2000 rpm of motor speed it will start to charge the 48 volt bank. the faster you go beyond that down a hill without stopping the more regen you will get. The other complicated way to get regen is to charge a 12 volt bank at a lower speed then switch 4 batteries from parallel to series to power the motor. The other way is to buck boost the 3 phases with a electronic voltage doubler to start charging the 48 volt batteries at a lower rpm with some control features so that it will not stop the vehicle completely. This is difficult to achieve on a light weight vehicle with a slight grade. If the vehicle was heavy and you had a long steep down hill grade or rapid stops it would be more effective.
From what I see the best way to achieve your goal is with a efficient genset running full time at it's optimal speed full time to charge lithium batteries.
The Honda 1000 watt genset weighs 29 lbs with a 120 volts AC output or through it's inverter at 12 volts DC. Using 12 volts to charge up batteries in parallel will be too much inverter losses and to efficiently run a higher voltage motor you will need to switch the batteries to series in the run mode.
You would be best off using the 120 volt AC output and have a efficient inverter made to match your DC battery and motor input of 48 volts to 90 volts what ever you decide on. The higher the voltage the less inverter and resistance losses through the system.
Now you can charge your batteries full time using them for your capacitor to use the motor efficiently at all times and conditions accumulating Lithium battery energy until you run out of gas. On the down hill legs with little or no motor power you will be coasting will getting a 100% charge from your genset. You will have to monitor your battery voltage to prevent over charging. It would be nice to have a electric starter and a system to turn off the genset then the batteries are toped off but at least have a buzzer to tell you when your battery voltage is at the cut off point as recommended for your batteries to stop the charging and turn the genset off manually then restart it again after 15 minutes of battery only use. FORGET REGEN BRAKING! and have a freewheel inside the rear wheel sprocket . This is about the same way a Chevy Volt gets 48 MPG starting off with uncharged batteries. :)

[gkamysz]

Isn't regen all about recovering wasted energy? Braking usually. If you can coast down the hill or to a stop without exceeding a safe speed or the posted limit, regen is not doing you any good. If you need to slow faster than air and mechanical friction slow the vehicle, regen will return some percentage of that energy that would go into heating brakes.

If it turns out that regen is worthwhile why would anyone choose a system other than a motor control with regen capability built in?

Greg

[BobDiode]

Isn't regen all about recovering wasted energy? Braking usually. If you can coast down the hill or to a stop without exceeding a safe speed or the posted limit, regen is not doing you any good. If you need to slow faster than air and mechanical friction slow the vehicle, regen will return some percentage of that energy that would go into heating brakes.

If it turns out that regen is worthwhile why would anyone choose a system other than a motor control with regen capability built in?

Greg How many seconds will you use your brakes hard enough to use regen in a light weight vehicle on a 2% grade in a 18 mph race? Letting off the throttle will slow you down fast enough unless you want to stop fast. Regen may be worth while to invest in a complicated regen braking system that will actualy give you a slight benifet on a 2500 lb vehicle stopping or slowing down fast all the time. Carrying along one of those flashlights that shake up and down to charge them will make more power bouncing on the trip than stoping fast a few times with the best regen system. For each time you have to stop you will be wasting more energy getting back up to speed than the amount of regen you could get.

[jmygann]

i asked the seller and he said ...

"A quad core is build for HIGH AMPERAGE and most of the super cores are build for high voltages."

He would not offer an opinion on making a motor

The thing is the alternators are rated for output(charging) not input (motor).

So which alternator to choose to make a motor

assuming ..

50+_ volt battery pack
20-30+_ amp draw continuous = 1000-1500 watts
24 in wheel
sram DD hub
Extron Kevlar #219 Composite Sprocket -72-92+_ teeth
Maintain 30mph

the SC18F alternator ?? or something better ?




The Quad Core relates to the #12 stator. Super Core relates to the Rotor with 14 magnets.

My guess is since the stock 12 Volt Delco stator has the thickest wire and the least windings. They may have added more copper by running 4 strands of thinner wire 1/4 the size in parallel to put more windings of copper on the stator to increase the amperage with less resistance. It would spin much too fast to be used as a motor unless you used it at 12 volts at a high amperage and rpm. But again that is only a guess.
You can pick up a standard 12 volt stator on ebay for $27.00 or for less at any junk yard.

[gkamysz]

The thing is the alternators are rated for output(charging) not input (motor).

This makes little difference. It will actually be able to handle more input power as a motor, assuming the generator rating is electrical output power. The only difference is shaft speed.

How many seconds will you use your brakes hard enough to use regen in a light weight vehicle on a 2% grade in a 18 mph race? Letting off the throttle will slow you down fast enough unless you want to stop fast.

That's exactly my point. If you don't do the math and you don't realize that any energy already built up in vehicle speed is better dissipated by coasting than regen, you won't see the light. Regen would be just as useful in a light weight, low drag vehicle, IF[I] there was braking involved. If you can't avoid braking, such as driving in city conditions, regen is beneficial. I think we all understand that one continuous speed is efficient, but not always. Maybe you are familiar with pulse and glide hypermiling techniques. One must evaluate the entire situation to draw a valid conclusion. For a small vehicle there isn't much investment in regen. Kontronik and Lehner ESC have regen built in. I can't vouch for how well they work, but I know I get current out of the motor/ESC while braking and it's easily controlled. Why does weight have anything do do with regen? A lighter vehicle needs less energy to get to speed, so you'll get less back during regen braking. I understand that how much you recover is dependent on drag during the higher speed parts of the decel. Of course, if your vehicle is draggy and light, then regen won't give much of a return.

If a vehicle in this sort of competition can do 30km/h on 15-20W, how will a motor capable of 10kW be efficient? The idle losses for such a large motor are greater.

Greg

[BobDiode]

This makes little difference. It will actually be able to handle more input power as a motor, assuming the generator rating is electrical output power. The only difference is shaft speed.



That's exactly my point. If you don't do the math and you don't realize that any energy already built up in vehicle speed is better dissipated by coasting than regen, you won't see the light. Regen would be just as useful in a light weight, low drag vehicle, IF[I] there was braking involved. If you can't avoid braking, such as driving in city conditions, regen is beneficial. I think we all understand that one continuous speed is efficient, but not always. Maybe you are familiar with pulse and glide hypermiling techniques. One must evaluate the entire situation to draw a valid conclusion. For a small vehicle there isn't much investment in regen. Kontronik and Lehner ESC have regen built in. I can't vouch for how well they work, but I know I get current out of the motor/ESC while braking and it's easily controlled. Why does weight have anything do do with regen? A lighter vehicle needs less energy to get to speed, so you'll get less back during regen braking. I understand that how much you recover is dependent on drag during the higher speed parts of the decel. Of course, if your vehicle is draggy and light, then regen won't give much of a return.

If a vehicle in this sort of competition can do 30km/h on 15-20W, how will a motor capable of 10kW be efficient? The idle losses for such a large motor are greater.

Greg
What is a idle Loss? When I use a motor it is in use or it is off The idle loss of the controller is about 4 watts. 20 watts of power out is just that and the size of the motor has nothing to do it as long as it can provide the same performance and efficiency spinning slow with more torque than a small faster motor with more reduction. The weight difference is not a huge factor when it is only a couple of pounds difference. A high rpm motor often takes up more friction losses including the reduction than a larger slow spinning motor with more torque and a minimal reduction. A example is a two cycle engine compared to a four cycle engine.
Try the small 20 watt motor in real world conditions instead of on a flat track in a light weight streamlined vehicle with a small kid driving it.. Please do tell us how much the small motor and reduction weighs and what it's max power rating is? Also with regen, how do you coast if you have the perfect hill to not using the motor or brake to gain free speed and distance to maintain your desired speed ? If you don't have a manual clutch disconnecting your motor and chain drag that alone will slow you down fast when you don't want to slow down with no benifet of regen and having to use motor power when you don't have to otherwise.. Direct drive motors and chains or belt drives slow you down a lot when coasting that is why electric bikes use freewheels for the motor drives.

[BobDiode]

i asked the seller and he said ...

"A quad core is build for HIGH AMPERAGE and most of the super cores are build for high voltages."

He would not offer an opinion on making a motor

The thing is the alternators are rated for output(charging) not input (motor).

So which alternator to choose to make a motor

assuming ..

50+_ volt battery pack
20-30+_ amp draw continuous = 1000-1500 watts
24 in wheel
sram DD hub
Extron Kevlar #219 Composite Sprocket -72-92+_ teeth
Maintain 30mph

the SC18F alternator ?? or something better ?

These are the open circuit voltages. The freespin RPM is slightly below the charging threshold rpm if powered at the same voltage. The reason for this is the bearing drag when motor is powered at freespin. With all the torque these motors have you may never need to get beyond 75% of your full RPM if geared
8 to 1 using the sc 24 stator at 48 volts. If you use the SC 18 stator it may be close running it below 36 volts with less torque and more rpm. For your controler and battery voltage you need to look at the voltage specs of the controller you wish to use. Note With the Castle Controllers you can program in the amount of braking you desire if any. IMO the freewheel will do you much better on a bike without all the motor chain and motor drag when you are coasting.
STATOR VOLTAGE RPM AND TORQUE CACULATIONS (http://www.hydrogenappliances.com/pmacurves.html)

[gkamysz]

Note With the Castle Controllers you can program in the amount of regen braking you desire if any.

Which controller?

[jmygann]

the seller replies ...

"The QC12 is best for the 48 volt range.

The trick is that you need to get the THREE PHASE driver to send pulses at 3000 HTZ

to get up to about 9000 RPM or faster SO that the cooling fan takes all the heat away.

LINK http://www.hydrogenappliances.com/powerpmas.html "





These are the open circuit voltages. The freespin RPM is slightly below the charging threshold rpm if powered at the same voltage. The reason for this is the bearing drag when motor is powered at freespin. With all the torque these motors have you may never need to get beyond 75% of your full RPM if geared
8 to 1 using the sc 24 stator at 48 volts. If you use the SC 18 stator it may be close running it below 36 volts with less torque and more rpm. For your controler and battery voltage you need to look at the voltage specs of the controller you wish to use. Note With the Castle Controllers you can program in the amount of regen braking you desire if any. IMO the freewheel will do you much better on a bike without all the motor chain and motor drag when you are coasting.
STATOR VOLTAGE RPM AND TORQUE CACULATIONS (http://www.hydrogenappliances.com/pmacurves.html)

[BobDiode]

Which controller?

My mistake. Just programable braking. I doubt if it is regen.

[BobDiode]

the seller replies ...

"The QC12 is best for the 48 volt range.

The trick is that you need to get the THREE PHASE driver to send pulses at 3000 HTZ

to get up to about 9000 RPM or faster SO that the cooling fan takes all the heat away.

LINK http://www.hydrogenappliances.com/powerpmas.html "

What is the seller replying to? A 3 phase driver at 3000 HTZ sounds like a AC driver for a 3 phase AC motor.
Using DC the control is much different.
Bob is a smart guy but he does not know too much about BLDC motors and does not relize how great his 14 magnet rotor design is for a bldc motor. When he does the price will triple!
The larger case half can be replaced by a small vented case half like on the other side for a better air flow and thinner housing if you grind the shaft slightly to 17 mm to fit the larger bearing where the slip rings used to go. Or you can also drill holes in the large case half for increased air flow, but i doubt you will need it if geard right. At 48 volts you should see about 1700 RPM with a no load freespin with the SC 24 stator. A 30 amp load you should be spinning about 75% of the freespin RPM to keep things cool without a fan. When you are moving at 20 mph the wind blows into the motor but put the fan on if you like..
These motors work best at a 12 kHz* switching rate when powered by a BLDC controller.

[jmygann]

I asked ...

"I am looking to build a 48-52 dc volt motor and trying to figure which alternator to use ?

the SC18F alternator ?? or something better ? "


What is the seller replying to?


so which alternator to get ?? SC18F ??

[BobDiode]

I asked ...

"I am looking to build a 48-52 dc volt motor and trying to figure which alternator to use ?

the SC18F alternator ?? or something better ? "





so which alternator to get ?? SC18F ??

If you want a 4000 rpm motor at 50 volts get the SC 18
If you want a slower 1700 rpm motor at 50 volts get the SC 24 stator.
Take 85% of the motor freespin rpm of each to figure out what your MPH will be close to for max speed with your wheel size and a 8 to 1 sprocket ratio.

[jmygann]

so ..... is it the SC18 , SC24 , or SC48 ??

or does someone need to try it ?




If you want a 4000 rpm motor at 50 volts get the SC 18
If you want a slower 1700 rpm motor at 50 volts get the SC 24 stator.
Take 85% of the motor freespin rpm of each to figure out what your MPH will be close to for max speed with your wheel size and a 8 to 1 sprocket ratio.

[BobDiode]

so ..... is it the SC18 , SC24 , or SC48 ??

or does someone need to try it ?
Do the math for the SC 24 and your wheel size to find out your top speed. :)

SC 24 Stator

motor under load = 1445 rpm 4 to 1 reduction = 361 RPM = 28 MPH

26" wheel at 388 rpm = 30 mph

16 tooth motor freewheel sprocket

64 tooth wheel sprocket

[jmygann]

what would the amperage figures be ?

[BobDiode]

what would the amperage figures be ?
That depends. typically under 30 amps 40 on a steep hill .

[spad4me]

Another bob diode thread?

[BobDiode]

Another bob diode thread?

Another arm chair critic? :)

[spad4me]

Another arm chair critic? :)

Not really a critic Just some one who wants signal not NOISE.
Or ten year old tech foisted on me.

[BobDiode]

Not really a critic Just some one who wants signal not NOISE.
Or ten year old tech foisted on me.


Definitely Old Tec, but new less expensive parts put together in a simple package that you can't figure out yet!

Bye :)

[spad4me]

More noise . Just noise.

[Christian Lucas]

Hi,
are there any dyno test of the motor build with this stator.The plates are not designed for permanent high flux magnets and the material used for this alternatorplates are normaly cheap and worst quality.

[Ron van Sommeren]

BobD/Randy, Spad, I think we're hijacking this thread a bit. Haven't seen the TS for a while now. Better stick to the How to Convert an Alternator to A Motor (http://www.rcgroups.com/forums/showthread.php?t=905411) thread.

Prettig weekend ;) Ron

[sneu]

Hi,
are there any dyno test of the motor build with this stator.The plates are not designed for permanent high flux magnets and the material used for this alternatorplates are normaly cheap and worst quality.

The short answer is "no". This whole thing seems to be a discussion that lacks much in the way of any useful data. DiodeBoB seems to be intent in promoting rather than informing.

The subject of materials and iron losses was brought up in the other thread but the data was never produced.


Steve Neu

[BobDiode]

For us fuel cells are not really an option. There are fuel cell cars at competition, however they are in a different group than we are. The hybrid would still be considered part of the combustion engine group because all of the energy comes from the ICE.

For regen, I do not know for sure if whether it is better to just coast down the hills or to regen and hold ourselves at a fixed speed. It is difficult to know what is better until we can determine what the efficiency of the regen would be. Regen would be better if the energy gained after losses by regen is greater than the increase in drag on the car caused by traveling at twice the normal speed. I can say for certain that regen would be the correct way to go if the regen was 100% efficient because loses due to drag do significantly increase with speed. Clearly we won't be regening at 100% though.

Right now we think the greatest benefit of the hybrid drivetrain is the fact that we can then run the ICE engine at a constant RPM. This should increase our efficiency immensely.

Right now for regen we are not necessarily thinking about buying a generator. Could we not just buy a medium sized efficient electric engine to act as a generator? Clearly it would be more complicated than that, but I don't think we necessarily have to use a large generator.

Nate

Hi Nate, Getting back to the subject of motor and engine. What are your new thoughts?

The idea of using a small RC motor as a wheel drive would be great but only if always using it when your in it's narrow Torque RPM Efficiency zone a at a certain vehicle speed. Use the gas engine on a separate system or wheel and have a way to have both the motor engaged (a manual wheel clutch) for regen breaking or for one or the other propulsion or both. To get a good regen at any speed you will have to reasearch a regen BLDC controller for the motor and voltage.
If a RC motor is too small the speed/efficiency zone is small. if too big your low power efficiency will be lost.
Here is a example of a electric bike with a large RC motor and a multi reduction gearbox. The motor takes 3.7 amps just to spin even at low rpm. At 11 volts is 40 watts of power. As your speed goes up the wattage losses also increase until you are in the RPM zone for max efficiency.

Terminator 30-8 at best efficiency of 89% at 36.2 Volts X 101 Amps = 4.232 Watts. For it to run a race bike efficiently it will require a bike speed of 65.1 MPH to use that much power to make the motor run efficient. Anything of lesser power the efficiency starts dropping. With the motor geared to a large ratio of speeds the motor would be useless as far as over all efficiency goes.

Since the gearbox will eat up 15% or more of the power I guess it wont quite have to go 65 MPH to reach the efficient motor power zone.

Here is a slection of motors to pick from for a narrow power/efficiency zone.
http://www.dualsky.com/main.asp?mainset=31

[Christian Lucas]

Hi Steve,
possible i know the dyno result .

Hi Nate,
all your questions are answered in the book "The world´s most fuel efficient vehicle" you can order from the Univercity ETH Zürich Switzerland,ISBN 978-3-7281-3134-8 ,e-mail: paccar@ethz.ch ,or on there site www.paccar.ch .

In this book you will find all information you are asking here for .example :they have test run with different motors ,sensorless blc and brushed Maxon motors .At last they have used the brushed Maxon motor and they have two at the wheel .Two for accleration and after they simply turn one motor pinion out of contact of the big toth gear by a servo. .They have done many test with the wheels and the stearing system.
They have a straight front axle with slightly inclined wheels ,for better aerodynamic,and stear the rear single wheel with the motors.To get such car it´s good to copy a lot of the work that has figured out to be very efficant.What kind of motor and and drive system you will use can change a lot of the peformance .

When i was 23 years old i build a fuel efficant car with my frind and we start at the Shell Kilometer Mataton at the Hockenheim raceway in Germany.We build a tree wheeler with a reworked Hond 50ccm four stroke combustion engine.No aerodynamic canopy only the aluminium frame .We reach 248 km distance with one liter fuel .Not bad ,third in it´s class but hundred billion steps away from the 5385 km of the paccar.
It was very much fun and we learn a lot .

[rich smith]

To get such car it´s good to copy a lot of the work that has figured out to be very efficant.

Ahhh... a statement from a very intelligent person. :)

Years ago I gave up large vehicles in favor of small motorized bicycles. Not for medical, legal, or economic reasons but personal choice. So this subject is near and dear to my heart.

To discuss gas and electric in the same breath is quite pointless. There have been some interesting experiments with electric, gas/electric, fuel cells, etc. but for practical transportation petroleum is currently our only option.

[jmygann]

so what is the most efficient brushless motor e-bike/trike ??

[wright100]

Hey guys,

Sorry I havn't posted in awhile. We had a project proposal due on Friday, so the majority of my time this past week was spent doing that.

Because this is a senior design project we have a "customer" who is the advisor of the Supermileage team at my school. Certain things are specified by him as requirements. We are pretty much stuck in a series hybrid configuration, we have to build a hybrid system, and regening ability is required. This is not to say that we have to regen during the race, but the capability is required for the project.

Here is our plan at the momment: We are still in the research phase of the project. In the next few weeks we will begin designing and I will let you know more. In fact, not enough research has been done to fully know whether or not our ideas are really possible... But here it is.

A large RC motor will be used as a generator off the ICE. A the start of the race we will run the ICE at its most efficient RPM and generate a certain amount of power which will be storred in a "storage device" (most likely ultra-capacitors). Once the power is generated we will begin to accelerate the car to 15 mph, which we will do our best to hold constant over the rest of the race (unless we return to a burn coast strategy). To actually power the car a smaller RC motor will be used. We calculated that to move the car up a I think it was 2% grade with a 25 mph headwind would require 555 watts.

At the top of the hill we would either coast or regen down the hill. In order to regen down a 7% grade we have to accept about 700 watts. This would either be the same as the previously stated motor or a different one. This kindof depends on what kind of efficiency curves we find. If it is different we would have to clutch it somehow.

Therefore we are looking for a electric motor that is capable of putting out 500 to 700 watts. The difficulty is that on a flat surface it only requires 38 watts to maintain 15 mph. Therefore either we need a really beautiful efficiency curve or we have to burn and coast slightly. Maybe burn to 17 and coast to 13. That way it requires more power from the engine allowing us to run at the efficiency level we want. We would optomize the burn and coast range for the efficiency of the motor.

Whenever we need power we will run the ICE and generate a certain amount then shut it off. The goal is to have to start it as little as possible.

Over the past week or so I have been working with a Mechanical Engineer to create some equations that define the energy usage of the car. I wanted to be able to determine with aerodynamic drag and rolling resistance what the top speed would be at the bottom of a user-defined hill and how far the car would coast. I created a second program that determines the amount of regen power that results from traveling down a user-defined hill. My goal is to generate some graphs that compare regen to coasting so we can get a real feel for what is going to happen with these two strategies. Hopefully I will get to that point sometime next week. I will attach those graphs up here when they are done.

Thankyou to the guy who posted the link to that book. I am going to take a look at that and will probably get a copy for the team if it looks like it would help us.

Nate

[BobDiode]

Hey guys,

Sorry I havn't posted in awhile. We had a project proposal due on Friday, so the majority of my time this past week was spent doing that.

Because this is a senior design project we have a "customer" who is the advisor of the Supermileage team at my school. Certain things are specified by him as requirements. We are pretty much stuck in a series hybrid configuration, we have to build a hybrid system, and regening ability is required. This is not to say that we have to regen during the race, but the capability is required for the project.

Here is our plan at the momment: We are still in the research phase of the project. In the next few weeks we will begin designing and I will let you know more. In fact, not enough research has been done to fully know whether or not our ideas are really possible... But here it is.

A large RC motor will be used as a generator off the ICE. A the start of the race we will run the ICE at its most efficient RPM and generate a certain amount of power which will be storred in a "storage device" (most likely ultra-capacitors). Once the power is generated we will begin to accelerate the car to 15 mph, which we will do our best to hold constant over the rest of the race (unless we return to a burn coast strategy). To actually power the car a smaller RC motor will be used. We calculated that to move the car up a I think it was 2% grade with a 25 mph headwind would require 555 watts.

At the top of the hill we would either coast or regen down the hill. In order to regen down a 7% grade we have to accept about 700 watts. This would either be the same as the previously stated motor or a different one. This kindof depends on what kind of efficiency curves we find. If it is different we would have to clutch it somehow.

Therefore we are looking for a electric motor that is capable of putting out 500 to 700 watts. The difficulty is that on a flat surface it only requires 38 watts to maintain 15 mph. Therefore either we need a really beautiful efficiency curve or we have to burn and coast slightly. Maybe burn to 17 and coast to 13. That way it requires more power from the engine allowing us to run at the efficiency level we want. We would optomize the burn and coast range for the efficiency of the motor.

Whenever we need power we will run the ICE and generate a certain amount then shut it off. The goal is to have to start it as little as possible.

Over the past week or so I have been working with a Mechanical Engineer to create some equations that define the energy usage of the car. I wanted to be able to determine with aerodynamic drag and rolling resistance what the top speed would be at the bottom of a user-defined hill and how far the car would coast. I created a second program that determines the amount of regen power that results from traveling down a user-defined hill. My goal is to generate some graphs that compare regen to coasting so we can get a real feel for what is going to happen with these two strategies. Hopefully I will get to that point sometime next week. I will attach those graphs up here when they are done.

Thankyou to the guy who posted the link to that book. I am going to take a look at that and will probably get a copy for the team if it looks like it would help us.

Nate
Hi Nate, Give some thought to using two of these Kollmorgan 24 Volt/VDC 300 Watt Brushless Electric Motors. Kollmorgan makes some of the best designed motors in the world. You can use one of or two of them with 8mm roller timming chain to a 100 tooth sprocket mounted to a Sram Dual Drive 3 speed internal gear hub on a 14" wheel. The motor would provide more torque with less gearing losses than a high rpm RC motor will privide with a better overall efficiency. From the fixed 1 to 1 second gear ratio you can drop down to first gear which is about 73% lower than second gear or go to third gear that is 137% higher than second gear for more top end speed. You can adjust your primary chain reduction accordingly. If you need regen a seperate 6 volt motor with a small wheel with a timming drive reduction to the motor on a lever to to engage to the wheel or ground for regen braking may be the best way to achive it at all speeds without a buck boost in the controller. Two motors can run the wheel one at a time or both in parallel to climb the hill or have the other freewheel. The sram hub will freewheel them both when coasting. I think you will require batteries to store power? Caps may only hold a small charge?
Your genset is another matter if you are trying to match the performance of a 29 lb Honda generator for efficient charging.?

http://cgi.ebay.com/Electric-Bicycle-Scooter-Brushless-24V-24-Volt-DC-Motor_W0QQitemZ350242678278QQcmdZViewItemQQptZLH_D efaultDomain_0?hash=item518c172606&_trksid=p3286.c0.m14

[larryross]

hey Bob I just saw this post and I want a truck load of those 200watt 2 horse power electric motors. Of course that efficiency will have to be verifiable. That would be around 350% efficient wouldn't it?:D :D


Knowing all the details will help. What kind of hills ? how steep and long ? At what average speed? What are the wind conditions ? How many watt hours of batteries can you take and what chemistry of batteries are allowed ? It sounds like you need a vary efficient 200 watt to 2 Hp electric motor. A #219 or 8 mm gokart roller chain with about a 8 to 1 ratio with a composite sprocket on the wheel with Sram Dual Drive 3 speed hub with slow moving planetary gears in the hub that freewheels while coasting incorperated with a Robins 50 cc motor and the efficient PM alternator motor to drive the wheel directly. I would NOT put regen on it because you will have a better advantage coasting freely.
Another option would be to use the PM motor to always drive the wheel by batteries and when your battery power runs out have the Robbins 50cc motor coupled to a different PM alternator with a non cogging 7 pole rotor Salant Core 7 pole rotor design for under $200. that you just missed on this Ebay auction.
http://cgi.ebay.com/SCS-PMA-12-24-48-V-Wind-Turbine-Alternator-Generator_W0QQitemZ300343281667QQcmdZViewItemQQptZ LH_DefaultDomain_0?hash=item45eddac803&_trksid=p3286.c0.m14
On both the motor or alternator you can adjust your Voltage/RPM = KV or torque= KT by your slection of 6 stator windings to meet your needs.
http://www.hydrogenappliances.com/pmaparts.html
http://www.hydrogenappliances.com/pmacurves.html
http://www.hydrogenappliances.com/powerpmas.html

[larryross]

No... I want the 200 watt 2 hores power one. And your right I don't have the brains to do that one, but would be more than willing to learn that trick!!!! :cool:



If you had a need for a decent motor that you can not find off the shelf to efficiently work for your project with a higher torque at a lower rpm with minimal reduction you may be suprised at the results of the 200 watt to 2000 watt motors you can make yourself for under $50. if you had any brains at all.

[Ron van Sommeren]

...if you had any brains at all.Reported, again. I'm not going to let you cripple this thead with your insults too as you did the other thead(s):
http://www.rcgroups.com/forums/showthread.php?p=13243135#post13243135