Brushless RPM Sensor/Tach from Eagle Tree Systems, LLC

[billpa]

Brushless Motor RPM Sensor from Eagle Tree Systems, LLC

Eagle Tree Systems is pleased to announce our innovative new Brushless Electric Motor RPM Sensor/Tachometer. Our Brushless RPM sensor makes it extremely easy to measure RPM with any of our Eagle Tree data systems.

http://www.eagletreesystems.com/accessories/images/brushless-rpm-sm.jpg

To measure RPM on your brushless electric Plane, Heli, Car or Boat, just tap one wire from our tiny new sensor into one motor lead, enter motor parameters in our software, and you are ready to go!

The Brushless RPM Sensor is compatible with our MicroPower, PowerPanel, Seagull and Data Recorder products, and will be shipping to our dealers and customers on approximately December 14, 2006 (just in time for Christmas)! Preorder yours today!

http://www.eagletreesystems.com/images/brushless-screen-sm.jpg

See your Dealer, visit our site at http://www.eagletreesystems.com or email sales@eagletreesystems.com for more information.

http://www.eagletreesystems.com/images/brushless-graph-sm.jpg

Note: Using the Brushless RPM Sensor with our Seagull and Data Recorder products requires firmware level 4.XX or higher, which has been shipping since approximately August, 2005. Click here (http://www.eagletreesystems.com/Support/Manuals/Upgrade-Info.pdf) for Upgrade Info (PDF).

[JIM CALDWELL A]

Bill, How many RPM will it log on 2 and 4 pole motors?

[swatson144]

I pre ordered one how's the shipping coming along?

Steve

[xStatiCa]

I ordered one on the 4th. I am not in a hurry though... whenever it is ready I am sure they will ship it. It would be nice to get an update though since the website now shows the 15th but it still says it is pre-order.

I am looking forward to this. Anyone know a good connector to use for the ESC/motor tap wire? It shouldn't need much amperage I assume so I was thinking of a simple servo connector on it.

[swatson144]

I think I'm just gonna skin the HS off one bullet connector and add a tap with the female end of a DB pin ( about 3$ for a db 25 printer kit from radio shack) Then repeat for each heli I want RPMs on. Putting a male on the sensor will allow pretty easy portability. Sorta like a micro bullet connector.

If you have only a few airframes to use it on you might be as well off taking the plastic ends off a servo extension and using the pins/sockets. That'd get you 3 done with no crimping, as you can use the attached wires.

Everything would of course be covered with small HS tube like the bigger bullets.

Steve

[billpa]

Hi All,

We have been the unfortunate recipients of this:

http://www.komotv.com/news/4935976.html

We now have power back on, and are using cellphones for internet access.

The mail has started to run again, and we are supposed to receive the brushless expanders from the factory today, which means shipping starting tomorrow.

Sorry for the delay!

Regards,

Bill, for Eagle Tree Systems, LLC

[xStatiCa]

Hope everyone is alright after a storm like that.

Thanks for the update. Any update to the update? ;)

[billpa]

Hi All,

Thanks for your patience. We are shipping the Brushless starting today! We'll get all the preorders out as quickly as possible, presumably by Friday.

Regards,

Bill, for Eagle Tree Systems, LLC

[xStatiCa]

Got mine today. All hooked up but should I use 1:1 for gear ratio for Align 430L motor? I used 11.538 (150t / 13t) for gear ratio and 6 poles and it seems like the RPM values are almost 12 times more than they should be.

[billpa]

Hi xStatiCa,

Can you graph "Prop RPM/Headspeed" and see if that looks correct? The "RPM" field is actually the true motor RPM. We need to relabel that to make it more clear.

Regards,

Bill, for Eagle Tree

[xStatiCa]

Thanks! That is all it was :).

I love this brushless RPM sensor. Much easier to get this to work than the other ones.

[xStatiCa]

How does the 'I want high resolution RPM' advanced hardware option affect tthis sensor( or does it)? Is there a downloadable PDF that explains some of this stuff?

I can't use the help menu option with the software because windows vista does not have the older help system anymore. I don't know if it is explained in there or not.

[billpa]

Hi xStatiCA,

That option increases the resolution of RPM readings, especially at higher RPMs, but has the downside of somewhat reducing logging time.

Looks like we've got some work to do for help with Vista!

Regards,

Bill, for Eagle Tree

[xStatiCa]

Thanks for the info. Sounds like I want to enable it.

[Bthree]

Bill,

An enhancement please,
I have a number of twin engined electrics Gws-262, GWS-38, A10, and others

Could we have two RPM sensors with a graph that plots rpm differential that would be real handy for setting up throttle curves and balancing motors.

[billpa]

HI Bthree,

Thanks for the suggestion! Our Flight Data Recorder will do this. It supports 2 RPM sensors, and graphing of both is supported. We could easily add a differential graph of the two if desired.

Regards,

Bill, for Eagle Tree

[Bthree]

HI Bthree,

Thanks for the suggestion! Our Flight Data Recorder will do this. It supports 2 RPM sensors, and graphing of both is supported. We could easily add a differential graph of the two if desired.

Regards,

Bill, for Eagle Tree

Would that be possible with the MicroPower E-Logger

[f5b@wannabe]

Hi

any ideas when this one would be available in europe ?

[Marv829]

HI Bthree,

Thanks for the suggestion! Our Flight Data Recorder will do this. It supports 2 RPM sensors, and graphing of both is supported. We could easily add a differential graph of the two if desired.

Regards,

Bill, for Eagle Tree

From the picture it looks like one sensor can do two motors. One wire to each motor, or am I reading that wrong?

-Marv

[billpa]

Hi,

The Brushless Sensor only does one motor, but you can have two brushless sensors with the Flight Recorder. The MicroPower won't do two RPM sensors -sorry!!

Bill, for Eagle Tree

[mjdoz]

Bill,
I just received my Brushless RPM Sensor from Extreme Radio Control (www.extremerc.com.au) and note that the package states:
"for Data recorder and Micropower V2"
but the Eagle Tree site and instructions state:
"MicroPower (all versions) ...... and Data Recorder V2"

Which is correct?

As I have one of the origional V1 MicroPower units is there anything I need to do to use the sensor unit? I have updated the software to the latest BETA version on your site.

Thanks

Michael

BTW great service from Extreme (Overnight) and for less than the standard postage cost alone if I had to buy from the US - not a complaint just happy I was able to find it locally

[billpa]

Hi mjdoz,

The package label on some of the early Brushless sensors incorrectly stated that they were for the MicroPower V2 only. They will work just fine on either the MicroPower V1 or V2. We have since fixed the label.

Note that the ONLY difference between the MicroPower V1 and V2 is that the V1 requires the 4 wire optical sensor.

Regards,

Bill, for Eagle Tree

[mjdoz]

Thankyou

[lamwan]

xStatiCa

yes, after you graph "Prop RPM/Headspeed and got the correct date/value on the PC screen. But i have a questions, how about by using the power panel LCD display. It seem the value is very high. So the rpm value on the LCD display is meaningless.

Bill , how to solve this problems on LCD display , i am got no idea.

[skeppley]

Thanks You Eagle Tree! Been running it on a Trex 600 with fantastic results. It can easily show what Lipo's are up to the task, and what different blades and pinions will do to the headspeed, amps and motor/lipo temps.
Great product!

Shane

[lamwan]

Who guy using the new brushless rpm sensor and monitor by power panel LCD display. What value are you show on LCD . I am got 2xxxx rpm by testing the Trex SE , it seem 10 time of the real rpm .
Bill can you answer this problems. Thanks.

[Bthree]

lamwan, you would expect an RPM in the 20-30K rpm range for a brushless motor

That is not the rotor head speed though you need to setup the gearbox ratio in settings to have head speed

[lamwan]

yes, i do set the ratio 11.538 : 1 (main gear 150/ motor pinion 13T). So the rpm range would be around 2000-3000. But the problems is the datd show on the LCD display is 10 time of rpm.

[mjdoz]

Bthree,

Did you set the number of poles (Magnets) for the motor? I don't have the LCD display so am just guessing but that certainly fixed the RPM when I was displaying it on the PC.

It appears that you have to make the change to the setup, clear the logger and collect new data to see the effect.

Michael

[shanghai_fool]

Sorry I didn't see this earlier. I ordered 2 today. This especially helps as my 2 motors are on 10.5" tubes and no more space in the tube.

Donald

[dalehart]

I don't know if anyone else noticed this yet, but the instructions for the brushless rpm sensor says that all inrunner motors are two pole. When I used this information to set the number of poles, My RPM readings were double what they should have been. I switched the setting to 4 pole, and everything looked right. This was with both a Medusa motor and a Warp 4 motor. I looked through the instruction sheet for the Medusa, and found that it said all of their motors are 4 pole design. Apparently this is true for the Warp 4 motors also. When I tried a Himax 2015, that one worked correctly set on 2 pole.

Dale

[Marv829]

I'm having an RPM reading even when the motor is not spinning. It shows about 4k-5k both in Live mode and recording. This is testing a Castle Creations Mamba Max 7700 motor/esc. It shows the reading regardless if there is one or both wires attached. The poles are set for 2. Any ideas?

Marv

[shanghai_fool]

Mine is working ok except it is more noisy than the optical.
http://www.rcgroups.com/forums/showpost.php?p=6976145&postcount=2
Chart showing difference. Both with Dualsky ESC and motor.

Donald

[Bthree]

I'm having an RPM reading even when the motor is not spinning. It shows about 4k-5k both in Live mode and recording. This is testing a Castle Creations Mamba Max 7700 motor/esc. It shows the reading regardless if there is one or both wires attached. The poles are set for 2. Any ideas?

Marv

It has been mentioned elsewhere in these threads that if you have selected brake on CC controllers feed power pulses to the motor to hold it/slow it down

[Marv829]

After playing with it some more I found out that I get an rpm reading simply by having the sensor attached and by touching one of the sensor wires with my fingers or if a sensor wire is connected to one of the motor wires even though the ESC/motor is not powered. It just picks up anything. The only time I don't get a rpm reading with the sensor plugged into the MicroPower is if the sensor wires are laying there by themselves not touching anything or being disturbed. Is mine faulty or are they that sensative. Also the rpm limit seems to be ~65k at which point the rpm numbers start over again.

[mpcrash]

I have the V2 with the brushless expander module. I am having a lot of trouble with a very noisy signal and the RPMs are jumping around about a 2k swing with occasional 25k jumps. Is there any way to settle this system down or is it normal for this sensor?

mike

[shanghai_fool]

Same here. Here is comparison -http://www.rcgroups.com/forums/showpost.php?p=6976145&postcount=2

Possibly add resistor between the 2 leads to reduce impedance or capacitor to filter?

Does it make any difference with both leads connected?

Donald

[billpa]

Hi All,

MPCrash/Shanghai_fool, sorry you are having a sensor issue. The first thing we need to do is to make sure you are running our latest software/firmware. Some changes went into application version 4.37 and later that could address your issues.

Here is a link to the latest:

http://eagletreesystems.com/LatestApps/Plane/beta/setup.exe

If you continue to have any problems, please email your .FDR files showing the issues to "support@eagletreesystems.com" and we'll get them checked out!

Regards,

Bill, for Eagle Tree

[Bthree]

G'day billpa,

Do you have to persist with setup.exe, more positive version identification would be appreciated.

In your post above there is no indication of which beta version we are looking at, I may have already downloaded that but the only way to tell is to install the setup.exe then check for version numbers !

Little point but frustrating to me.

[billpa]

Hi Bthree,

Sorry for the lack of indication in the name of the file. Here's a link to the support page, which shows the beta version (4.46 in this case).

http://eagletreesystems.com/Support/plane.htm

Regards,

Bill, for Eagle Tree

[mpcrash]

I will check and get back to you. Thanks Bill.

mike

[MarkChinery]

what is the max rpm of the brushless rpm sensor..?

[shanghai_fool]

Bill,

An enhancement please,
I have a number of twin engined electrics Gws-262, GWS-38, A10, and others

Could we have two RPM sensors with a graph that plots rpm differential that would be real handy for setting up throttle curves and balancing motors.

I second that!!

Donald

[wildpalms]

what is the max rpm of the brushless rpm sensor..?

I'm currently using one on an EDF and it seems to do 45,000rpm OK.

[andres.c]

Bill I am Trying to install the brushless sensor in my E heli the motor is a hacker a50-12L 14 pole max rpm 13,000 the heli gearing is 85main / 10 pinion straight to the motor shaft running a 12sp1 setup
what would be the settings for the motor ? 1 , 2 or .5 , .25 please help to calibrate to rpm sensor ..


any help is appriciated

[billpa]

Hi Andres,

First, are you sure that the 12s is not exceeding 45v? The logger should not be powered at > 45v.

Re RPM setup, the number of poles that should be entered into the software for Outrunners is normally equal to the number of magnets in the flux ring. Your gear ratio is 8.5:1 from your description, so just enter 8.5 in the gearing window.

You should then be able to see motor RPM and prop RPM correctly. Let me know if you have any other issues.

Regards,

Bill, for Eagle Tree

[The Don]

I recently purchased one at the Toldeo Show and it seems to be working just fine. I did have one question on how it works. Does this measure pulses going to the motor or pulses from the motor? The reason I ask is that the model I am flying goes about 90 mph. Before I launch I hold the throttle wide open to get a static amps and rpm measurement. Then I launch. Everytime the RPM goes down as the model speeds up. I thought the prop would unload in the air and rpm would go up. Then I started wondering how this actually measures the rpm. And could diving a model trick the sensor?

Don

[Watty]

I recently purchased one at the Toldeo Show and it seems to be working just fine. I did have one question on how it works. Does this measure pulses going to the motor or pulses from the motor? The reason I ask is that the model I am flying goes about 90 mph. Before I launch I hold the throttle wide open to get a static amps and rpm measurement. Then I launch. Everytime the RPM goes down as the model speeds up. I thought the prop would unload in the air and rpm would go up. Then I started wondering how this actually measures the rpm. And could diving a model trick the sensor?

Don

Don,

One possibility is the prop is stalled at zero airspeed and un-stalls as airspeed increases. In the stalled condition, the prop might not be absorbing as much power as in the un-stalled condition (it certainly wouldn't be producing as much thrust when stalled). If that's the case, it would could cause the input power to go up and RPM to drop when airspeed increases to the point the prop un-stalls. After that, as airspeed increases, the RPM should increase and power should drop as the prop unloads.

One way to investigate this is to look at the recorded input power as well as RPM (and airspeed, if you are using an FDR). For a prop that isn't ever stalled, the input power at full throttle will be highest at zero airspeed and RPM will be lowest at zero airspeed. Power will drop and RPM will increase as airspeed increases and the prop unloads. For a prop that is stalled, the recording of input power might show an increase just after launch when the prop un-stalls. Another clue would be an abrupt change in the sound of the prop after launch.

I have one of the Brushless RPM sensors, and find it to be a huge improvement over the magnetic and optical sensors. I've only found two things users ought to be aware of:

- It's easy to make an error in determining the number of poles, resulting in RPM errors. The only sure way to avoid errors is to double check recorded or displayed RPM with an optical or other type of tachometer.

- I have gotten RPM indications when the motor was off and prop not turning. The reason for that is some brushless controllers pulse the motor when the brake is on - even when the prop is stopped. To get rid of that, you have to turn the brake off. This might also result in a recorded current that is higher than expected (more current than required to run radio and servos) when the motor is off.

Hope this helps in figuring out what is happening in your application.



John

[The Don]

Here is a graph, you can see amps and rpm are max static before launch. Amps drop down as the model picks up speed, but the rpm drops as well. I did not expect that, I expected the amps to drop but the rpm to go up as the prop unloaded.

Don

[shanghai_fool]

I'm also getting confused here. After the initial surge, it looks to me like the RPM and power are inversely proportional or 180° out of phase.

Donald

[The Don]

That is why I was wondering how the sensor measures RPM. It does it with my other plane as well. Here is my graph from todays flight. Different plane and different motor.

I was thinking of hooking up the optical rpm sensor and the brushlees and recording both at the same time to see if they read differently. I just do not have good luck on the optical one reading my outrunner can.

[shanghai_fool]

I'm sure they just measure the frequency of the pulses which in a 3 phase motor is a pulse ~240°/motor poles long on each leg. Since you can also get a reading from rotating the prop by hand from back EMF, It doesn't matter which direction you measure. I think the decrease in power just means that the prop is unloading at that point. It will spin faster with less power.

I use the optical sensor if the motor is in the fuse. Since part of the outrunner case is black, I put a band of white monocote around half of it and mount the sensor about 1/16" on a small aluminum mount made from a piece of aluminum angle and mounted with one of the motor mounting screws. I use the brushless type in my twin engines where the motor is too far away.

Donald

[The Don]

I think the decrease in power just means that the prop is unloading at that point. It will spin faster with less power.

Yes but the RPM does not spin faster, that is what is confusing. I understand why the power goes down. I do not understand why the RPM goes down as well. My static RPM is higher than inflight RPM. That is what confuses me. Look at the first few seconds. Max RPM when static, I throw the plane and it accelerates, the RPM drops 1000 rpm as the model speeds up. I expected to see the power drop as the prop unloads, and also expected to see the RPM to go up as the prop unloads. Instead what I see is power drops as it unloads and RPM drop as it unloads.

The chart shows:
350 watts 26000 RPM static, then during the next 8 seconds as the model accelerated power drops to 290 watts (expected as prop unloads) and rpm drops to 25000 (unexpected). I then throttled back to adjust my flight trims. But all the max rpms occur when I climb up to an almost stall, then when I do split S and dive down back towards me, the amps and rpm go down as I dive. I understand the amp reduction, but not the rpm reduction.

Don

[shanghai_fool]

That certainly is confusing. I will be getting a varible pitch prop in a couple of weeks so I'll run some tests with it to see what the rpm does. Stay tuned.

Donald

[EatAtJoes]

Hi Guys

Made a short video of how to mod the RPM sensor to fit the Eagle Tree V3 Logger so that you can use the Throttle Port as stated in the PDF.

Enjoy

Eliashttp://www.youtube.com/watch?v=Uh8e-10HTnY

[Socomon]

Hi Guys

Made a short video of how to mod the RPM sensor to fit the Eagle Tree V3 Logger so that you can use the Throttle Port as stated in the PDF.

Enjoy

Eliashttp://www.youtube.com/watch?v=Uh8e-10HTnY

I am confused as to what this mod accomplishes.

[EatAtJoes]

I am confused as to what this mod accomplishes.

Without it you can not plug the brushless sensor into your throttle port of the logger.

So therefore if you use an optical RPM sensor and want to also use a brushless RPM sensor then this is the only way to achieve this sort of setup

For example
If used on a helicopter, you want to see when your motor stops spinning and also know how fast your blades are rotating, so you would use the brushless sensor for the motor and optical for the rotor blades, this way when you do what is known as autorotation you will know you are keeping the headspeed up high enough and know that your motor has stopped, giving you the ability to fly your helicopter to the ground like gliding your plane when the motor cuts.

or in a geared prop you may want to keep an eye on both the motor and the prop

Elias

[Socomon]

OK - got it. Thanks.