RC Groups - Electric Motor Design and Construction

Help! hexTronik 2 gram Brushless Outrunner 7700kv (D1000-7700)

rhari — Sat, 21 Nov 2009 18:09:13 GMT

Just bought this motor.

I am planning to build a Stechmucke http://www.bostonmicronauts.org/gj-a...stechmucke.pdf and wanted suggested on mounting it to a carbon fibre rod. If someone has already tried it out then please could you share any pictures.

thanks

Help! 10g 1811 rewinding

dieselBird — Sat, 21 Nov 2009 00:57:34 GMT

I bought the the 10g motor and have had success with it. Until the wires broke off, which in hindsight is all my fault for letting the motor hang by the wires (and having the motor break off in midflight and only remained attached by the wires).

Since I can't find the wires I figure I might as well rewind it. I've never done this before so any help would be awesome. I run a 2s 360mah battery. I loved how it ran with a GWS 6x3. I would like a bit higher rpm, but if I reduce the amount of winds I still want enough torque to swing the 6.3 prop.

Basically: What guage wire should I use and with how many winds.

Thanks for the help.

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Question What does advancing the timing actually do?

FlyingW — Fri, 20 Nov 2009 03:31:42 GMT

In Bob Boucher's chapter on motor timing and achieving sparkless commutation, he describes how at a certain amperage, the coil can change polarity no faster - it is at this point we can estimate the inductance based on the rpm and size of the commutator segment. I'm ok with that.

I'm also ok with how he explains that if the reversal of current is not complete by the time the brush moves over the commutator, that the trailing edge of the brush has to pass too much energy to do it gracefully (it burns). Ok.

But then he states that when advancing the timing, the brush "comes under the magnet" and this helps with the reversal of current in the coil that occurs during commutation.

Can anyone explain that in another way so I can get a better feel for it?

Thanks,

Paul

Help! squeeling in my motor

rcjetflyer2 — Wed, 18 Nov 2009 20:16:56 GMT

i have a 12 mm brushless motor that is for no reason squealing.
i was flying my plane with it and the speed of the motor dropped and it started squealing and it wont stop

whats wrong with it and how can i maybe fix it?

thanks

Question 30 m/m rotors

james m thompson — Wed, 18 Nov 2009 19:17:32 GMT

Hello
Can anyone tell me who sells 30 m/m rotors, thanks in advance.
James.

Question AXI 2820/10 magnets unstuck

MrCDM — Wed, 18 Nov 2009 10:01:50 GMT

Hi folks, I've just flown my plane into a fence. It's bad enough that I feel soooo stupid right now but I've also destroyed my plane and motor before it's maiden flight. The RX lost comms and it kept going.

The motor is an AXI 2820/10. Some of the magnets on the rotor have dislodged and I am hoping someone can give me some tips on how best to re-glue them.

Any tips would be appreciated.

Thanks

Discussion ESC size for CDROM motor ?

mtesa — Wed, 18 Nov 2009 08:26:34 GMT

I got a CDROM motor from a busted notebook CDROM (lightest of them all?).
Wired it to 8-10A ESC from HobbyCity and to 2S lipo.
Tried with several stick positions up to 80% of throtle without load at shaft.
When I pushed a stick a bit more, ESC gave away and went in smoke.

Is there any rule on ESC size for CDROM class motors with original wireing and magnets? And what about rewound ones with strong magnets?

Help! Supercub modified with T-28 brushless motor

orthotech — Mon, 16 Nov 2009 22:31:55 GMT

Has anyone modified a supercub with a T-28 motor. I have a hobbyzone supercub and a broken T-28. I would love to use this motor for the SC. Are there any plans out there??

Discussion building a gbx kit for speed

rotccapt — Mon, 16 Nov 2009 03:35:59 GMT

hi all i have a sig wonder that i would like to electrify with a go brushless gbx kit. my question is how would i wind it for speed and also how many stators would i need? i would assume i would need a double if not a triple. i would think a prop some where in the 6 to 8 inch range. i have built several gbx-1 motors so i have the know how for this project. my plan is for under 30A because that is the highest rated esc that i have and use my flight power evo 25 1800 mah 3s lipo.

Discussion Dented brushless motor

cityseagull — Sun, 15 Nov 2009 16:18:41 GMT

Hi guys,

I have a brushless motor (tower pro 2409-12a) with a small dent in the bell. Now it does not spin. I assume this is fairly common, but is it repairable? The dent is very small, it just looks like a scratch.

Many thanks!

Discussion Rewinding For A Helicopter.

MiseryQ — Sun, 15 Nov 2009 05:49:24 GMT

Are there any "extra" considerations to winding a motor for a heli?
I oreder this: LINK motor and while construction seems good, the kv is closer to 4300, it starts hard spinning the heli sometimes over 180� and requires a hard to find, local anyway, 9t 2.3mm pinion, (main gear is 140t).

I'd like to wind it to use an easier to source larger pinion and make it start softer with my Thunderbird 18 ESC. It starts smooth with a SuperSimple but the resolution is noticeably less.

Mostly toying with the idea as I don't know what if any benefit rewinding would actually have.

Discussion Mega 22/30/3 repair?

bjpaul — Sat, 14 Nov 2009 21:47:53 GMT

Anybody know a good way to take apart a Mega 22/30/3? It needs new bearings. The end cap in held in place by three stainless steel pins. Worst case I can drill them out unless somebody has a better idea.

Brad

Discussion Park 250 becomes hot.

Vibe Ration — Fri, 13 Nov 2009 13:05:59 GMT

Hi guys,

I have a Park 250 who received some bad nose crashes. It turns well but it gets hot and the flight time goes from 4m30s to 3m.

Is this fixable? Is there a way to open it?

Thank you!

Help! TURNIGY 50-65A 400kv Outrunner

Ronny Sleevs — Fri, 13 Nov 2009 10:29:28 GMT

Hi Friends !
I think you guys are my last change .. I'm trying to get started on electric
planes but the result so far were catastrophic !!!
Ok, let's to tell:
I like acrobatic and 3D flight and after seen a stunning video with a Edge from Kyosho I've decided it should be my first electric plane, so follow the
setup:
Airplane: Edge Kyosho
Motor: TURNIGY 50-65A 400kv Outrunner
Specifications:
Model : TR50-65A-400
Input Voltage : 14.8V~29.6V (4~8S Li-po)
Kv : 400 rpm/V �} within 10%
Current capacity : 60A/60s
Dimensions : 50mm X 65mm / 1.97in X 2.68in
Shaft diameter : 8mm / 0.31in
Weight with cables : 414g / 14.60oz
Number of poles/magnets : 14
Recommended model weight : 3000~4500g / 100~200oz
Power equivalent : .50 to .72 glow engine

My first choice for a a ESC was a TURNIGY K-Force 70A-HV OPTO Brushl,
but it has literally toasted on the first run, ok second choice of ESC:

TURNIGY Plush 80A w/ UBEC Speed Controller
Specification:
Cont Current: 80A
Burst Current: 90A
UBEC Mode: 3A/5v out
Voltage Range: 5.6v ~ 26v
Weight: 91g
Size: 88x31x14mm

Propeller:
XR Type B Beechwood 3D/SF Propeller 14x6

Batteries:
First flight with a Rhino 3700mAh 5S1P 20C Lipoly Pack
Capacity: 3700mAh
Constant discharge: 20C
Burst rate: 30C (15sec)
Configuration : 5S 18.5v

The airplane was incapable of vertical ascending, no power, total disappoint.

Second try:
Rhino 3700mAh 6S 22.2v 20C Lipoly Pack
Capacity : 3700mAh
Constant discharge: 20C
Burst rate: 30C (15sec)
Configuration : 6S 22.2v

Looks like much better but on the first test on a vertical climbing I've heard
a strange noise and motor stopped, for look I had a independent battery for the receiver so resulting in just small damages. After desconnected and reconnected the battery the Speed Control start to working again. But I''m
not sure if I will try again with the same configuration ..
So my ask is what can I be doing wrong ?
My configuration is wrong ?
Forgetting something ?
The motor is too big ? Too small ?
The speed don't stand the motor and I need a more powerful one ?
Any help will be appreciated :)
Thanks guys !
Ronny

Discussion Ebay find- Cobra Lathe.. Can I use it?"

Red5 — Thu, 12 Nov 2009 21:12:43 GMT

Can a cobra Pro Com lathe be of any use with brushless motors? There is one going cheap on ebay right now.

Question rewind a Hacker A10 possible

going4speed — Thu, 12 Nov 2009 00:33:46 GMT

I have a new hacker a10 that I would like to rewind for a 8*4 gws.

Possible or just sell it?

Discussion Inrunner shortcomings

olmod — Wed, 11 Nov 2009 12:02:54 GMT

The method used in making a star centre connection failed mainly because of misunderstanding that solder is not a very good conductor,
the centre wire comes for and aft along the inside of the housing and the other 2 wires come from the sides to form a T shaped butt soldered joint in wich the right hand side wire had a gap wich was origonally filled with solder,
wich should have had a % of silver content at the very least.
the integrity of the wire coating were not discoloured from too much current, the solder just melted because it had a higher resistance.
im sure a better designed termination in the factory would make this a much better motor.

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Discussion ELE C20 rewind

Flatulator — Wed, 11 Nov 2009 02:24:12 GMT

A while back I toasted a ELE C20 a friend gave me by using a prop a size or two larger than I was supposed to. He didn't remember what the kv was when he gave it to me so I didn't know what size prop to use. Anyway, I unwound it last night and it is an ABC wind with 19t of 2 strands 30awg terminated delta. Does anyone know the kv of this motor?

Discussion simple Q about induction motor

aabbddlah — Tue, 10 Nov 2009 23:36:57 GMT

hello

i v got a small question about induction motors

why does the steady state torqe is equal to zero when rotor speed is equal to 314 rad/s? and
why when rotor speed is for example is equal to 100 , torque maintain a higher positive value

many thanks

Discussion Rewinding brushed motors???

MarcRacer18 — Tue, 10 Nov 2009 06:20:47 GMT

Does anyone know of kit or some company that can rewind motors? Normaly i would just buy a new one but this one is vintage. Its a Cobalt 05 Marine racing motor 18-magnet 8-pole. I'm prety sure it was abused before i got it but i sure finished it off after one run. It's a very nice motor that has some historical value so if it can be restored it would realy be nice. Thanks for any help.

It might also be interesting to wind my own custom motors in the future, if possible :rolleyes: .

Help! Suppo Outrunner - How to diagnose failure

Rick_Soth — Tue, 10 Nov 2009 04:23:51 GMT

I have a fairly new Suppo 2217/19 motor that I crashed fairly hard and now the motor will not spin up. I have tested the ESC on other motors and it works fine.

I purchased a new shaft and replaced that thinking it must be the issue since it's on only replaceable part. No change.

There are some "scuff" marks on the magnets (I think) located on the outer ring. There are no apparent scuff marks on the winding faces (magnets?) on the inner core.

The motor is cheap ($20), so it's mostly an exercise in trying to understand how to test these things.

Is there some way to test the 3 lead electrical with my digital multimeter, to determine if there is a short or something?

When the ESC is connected and I apply throttle, I get a minor amount of "twitching" like it's trying to start, but nothing really happens. Adding to twist with my fingers doesn't work.

Any thoughts or suggestions would be appreciated.

Thanks.

Rick

Discussion help on 3 phase brushless mottor with 11 pins using

ender81 — Mon, 09 Nov 2009 09:50:59 GMT

I'm new in electronics and i wanted to control a motor using an atmega16. I have found an old cdrom, where i found a 3 phase brushless motor controlled by a BA6849FP. I am trying to find a way to connect the motor to the Atmega, but I have no idea how to do it. Another strange thing (at least for me) is that the circuit has 11 pins. I have measured the resistence between the pins to understand their use and i have found that there one group of 3 pins (1,2,7) and one group of 8 pins (3,4,5,6,8,9,10,11).
Can anybody help me how this motor works and if I could control it using an atmega16? (also I could detach the BA6849FP)

Discussion Motor ugrade for PK-T-28

larryb — Sun, 08 Nov 2009 19:56:56 GMT

I want to hype up my stock PK t-28 with a larger motor. The recommended motor seems to be the 3536 but it is too short for the stock motor mount.

I know I can get a modified motor mount off Ebay for $20, but was looking at some motors and found this motor that matches the size of the stock PK 480 for overall length and dia.

TR 35-42D 1000kv Brushless Outrunner (Eq: AXi 2820)

I am not worried about the mounting holes as I can drill new ones if needed.

Any one use this motor in the past and if so what prop size is recommended?

I suspect that a 8 to 9" prop would work with this low KV motor without drawing too much amps.

Larry

Discussion Is there a way to mount new motor on radian?

U124IXB — Sat, 07 Nov 2009 03:33:32 GMT

Because.....I just got a suppo in the mail today problem is the firewall mount whole are too small on the suppo need to be pointed to a good site with alot of mounting hardware.

Discussion New Plane

larseen — Thu, 05 Nov 2009 04:09:06 GMT

Hello

I am drawing a plane i am thinking of building, and the aileron flaps are getting quite big, is it normal to have two servos on one aileron and how do i wire two servos on one channel.
How much do I need to pay for a system that can handle 6-8 channels, quite large servos and how big range can i have with it ?

Does any one have a equation for how big motor (GAS) i need and how big wings i need for my estimated weight to acquire lift?

Discussion Lrk or Lrk?

SexyJet — Wed, 04 Nov 2009 14:33:04 GMT

Hi

I red about if you want a very high torq. motor, then you should go for
Lrk rewind??
(in the Pdf file that one can download!!)
that means that every other theath is winded? right?

But here in a german site i am reading the oposit. They build very high
rpm motors with the same rewind?

which one is right then?

http://translate.googleusercontent.c...3m-E2MifFtxQ9Q

Thank's

Idea south african cheeta fighter jet

ellement51 — Wed, 04 Nov 2009 11:02:18 GMT

Hi there everybody im real pleased to be here with all of you,Currently i am, busy with my own design the ex fighter jet,the south african cheeta .I will be posting some pics soon.Anyone interested ,please feel free to email me for the plans which i have currently completed. by the way we have just sold the origanal cheetas to south america for round $100, millon each, we have now purchaced th gripens from Sweeden for$80 million each. anyone needs more info call me thanks everyone. ex retired 2nd lt.jerome coetzee fighter pilot, south african airforce.:)

Help! Old motor

TLyttle — Wed, 04 Nov 2009 05:14:14 GMT

A buddy left me an old Simprop Pfalz kit, and I have a question about the motor: does it have internal capacitors, or do I need to add my own? It is a Simprop Speed 280, mounted in a ParcDrive 300+ gearbox. The instructions for the motor are in German... French, maybe; German, no chance!

Discussion Turnigy 3020 22-mag 24-tooth Rewinds

timocharis — Wed, 04 Nov 2009 03:39:05 GMT

A few of us have started fussing with these motors lately so it's time to start a thread. The impetus seems to be a recent "sale" at UnitedHobbyCityKing which is still on at this moment. You can see the stock motor BS here:

http://www.hobbycity.com/hobbycity/s...idProduct=9378

It's obviously bogus specs as usual. If you put a 9x4.7 prop on this 2S it would probably draw about twice the recommended max. An 8040 draws way over their limit. Here's the numbers for the stock motor:

Rm = 0.168
Io = 0.61 @ 7.98 volts
Kv = 1966
With 8040 prop and 2-cell battery, it produced 9253 rpm @ 7.44 volts and 10.70 amps. Badcock calls that 435 grams (15.3 ounces) of thrust @ 62.9% efficiency. Drive calc gives it 477 grams (16.8 ounces) @ 65.4% efficiency. In other words, pretty poor compared to a typical blue wonder, which has almost exactly the same weight.

It was wound with groups of four teeth in each phase, 9-10-9-10 turns to get a 9.5 average. Since there are 22 magnets and 24 teeth, there is no option save to do groups of four. 22 cannot be divided by four, so two-tooth phase setups are simply not possible. The motor as designed gives less cogging, but at the cost of phase-angle error. I do not know if it's a wise decision, but I do know it's very limiting as regards winding methods.

The motor is notable for having some resemblance to the Neutrino, a smaller lighter weaker motor that also has 24 teeth. Some components may be from the same manufacturer. However, there is almost no technical resemblance beyond the tooth count and some superficial looks. This motor is bigger and has 22 magnets rather than 26 (I think it's an inferior decision). Curiously, this one has better build quality than the Neutrino I saw, but the Neu was a proto supposedly.

They both share the characteristic of being underproductive for their size and weight, and having poor efficiency -- only in part due to humdrum winding.

Discussion Testing no-load rpm's with optical tach?

Flatulator — Tue, 03 Nov 2009 03:23:49 GMT

What is the proper procedure for testing rpm's with an optical tach? Currently I am using a popsicle stick mounted to the motor shaft in place of a prop. Is there a more accurate way to do this?