More power: two controllers driving a single brushless motor - RC Groups
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Jul 29, 2004, 10:44 AM
homo ludens modellisticus
Ron van Sommeren's Avatar

More power: two controllers driving a single brushless motor

I created a new thread to answer/discuss the following two questions that were asked in the 'Sport Planes' subforum, in the 40% Electric Extra 330S Flies At Joe Nall thread.

Originally Posted by allen1allen
Hello Ron, I just saw yours post were you mention using multiple controllers on one motor. Jochen Causmann is making me some 3000 watt motors, could you explain to us how to do this, or direct us to the information?

Craig Allen
High-Torque Motors (Germany) (USA)
Craig, using two controllers to handle more current is an idea I picked up from Christian Lucas (the 'L' in 'lrk'). I tried to figure out how to do it, I have not done/tested it myself. Have a look at the 'distributed' lrk winding below. You can look upon the motor as two 'classic' lrk motors on one shaft. To get more current, you drive coils 1,3,5,7,9 and 11 (wound as a classic lrk) from ESC1 and coils 2,4,6,8,10,12 (also wound as a classic lrk) from ESC2. There are two scenarios for the 'controller control.

Two ESC's on same channel:
Hook up controller 1 and make sure the motor is running in the right direction. Disconnnect controller 1, connect controller 2 and make sure the motor is running in the same direction. Now hook up both.

Two ESC's on two separate channels+mixer:
You could also use a mixer to have ESC2 kick in when ESC1 is at full throttle. ESC1 handles 0-50% throttle, ESC2 does the extra 50%. Advantage: ESC1 is working at full load most of the time, no partial load losses there.

Originally Posted by allen1allen
...What if I want to use more voltage ? I would like to use 46-50V and draw 65-70 amps.Any help would be greatly appreciated.
You would need FET's that can handle the current and the voltage. I'm not very familiar with analogue electronics, you could ask in the DIY electronics subforum:

Groeten Ron
Last edited by Ron van Sommeren; Jul 30, 2004 at 09:16 AM.
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Jul 29, 2004, 11:28 AM
Mad Max meets the Thinker
Cyberman's Avatar
Ron there is another way so to speak to do this.

Instead of what everyone has been doing which is 3 phase commutation with a single controller. You can use 6 phase commutation with 2 controllers. The controllers would have to be from the same manufacturer for this to work. This will give smoother cummutation, however you need to wind the motor yourself. Since 6 phase is not an off the shelf toy!

  1. More windings to share the load current so power is more broadly distributed.
  2. Smoother commutation instead of 120 degrees seperation per phase it's 60 degrees
  3. Allows you to use 2 controllers on SEPERATE sets of windings, thnk of it as 2 3 phase motors in the same housing.
  4. The controllers can operate independantly of each other this way, and shouldn't have problems spining the thing up.
  5. No change needed for higher amp controlers as it behaves like 2 synchornised but seperate motors. Thus it's an instant 2X power boost.

  1. New wind type for stator with 6 alternating phases.
  2. Controlers must be same make and model and production time because variations will mess up the commutation
  3. You have 6 or 12 wires to hook up to (see '2 Wyes' or '2 delta's').
  4. Might be tricky to get started and contollers may fight each other or get confused about the timing because of the synchronization.

This concept has been used for very large motors in driving big things like wind tunnels (example Nasa's current wind tunnel uses a 5megawatt 12 phase motor with controller just like this).

Jul 30, 2004, 09:15 AM
homo ludens modellisticus
Ron van Sommeren's Avatar
Stephen, what I described is effectively a six phase motor I changed my post slightly to make it clearer that two controllers are used. Yes, you will have 6 wires to hook up.

Groeten Ron
Jul 30, 2004, 01:31 PM
Mad Max meets the Thinker
Cyberman's Avatar
Originally Posted by Ron van Sommeren
Stephen, what I described is effectively a six phase motor I changed my post slightly to make it clearer that two controllers are used. Yes, you will have 6 wires to hook up.

Groeten Ron
Hmm it sounded more like paralleling 2 controlers

Ahh well, I plan on doing this for a significantly larger motor than the ones currently popular in models. Sadly it doesn't change the DC current going to the controller being rediculously high (sniff). I'm contemplating 12 or 24 phases.

Jul 30, 2004, 02:42 PM
Dieselized User
gkamysz's Avatar
I think that if you really tried you could seperate the strands of a Hacker motor to make two parallel circuits.

I have a large 12 slot lamination motor internal rotor I intend to wind 6 slots for one ESC and another 6 for another controller. Essentially the motor will be wired in halves.

Two ESC's on two separate channels+mixer:
Will this work? The Kv of the motor doesn't change regardless of the number of active parallel coils. The motor will try to pull full current if one of the ESC is at full throttle. Unless this characterisitc is specific to LRK.

Jul 30, 2004, 07:05 PM
Registered User
mmormota's Avatar
I am afraid there are serious problems with 2 controllers:
- The sensorless controllers have to sense the back emf voltage.
- There is another controller with asynchron PWM signal.
- The PWM signal most probably disturbs the sensing part of the other controller.
Aug 01, 2004, 02:59 AM
Registered User
THis is off topic but thought you guys would be able to answer this.

If I'm powering something with two or more brushless motors, how do I hook up two or more controlers to one Rx? Can the Rx leads of the controlers be hooked up in parallel?

Aug 01, 2004, 08:05 AM
homo ludens modellisticus
Ron van Sommeren's Avatar
The method I described is the same as two mechanically coupled motors (Two classic lrk motors sharing the flux ring and the shaft) Those can be driven with two controllers without a problem.

Coils 1,3,5,7,9 and 11 are 'motor 1', coils '2,4,6,8,10 and 12' are motor 2. There are no connections between the two motors. I know, a picture is worth ... But I don't have one.

Both controllers get their sync signals
Aug 01, 2004, 12:41 PM
Registered User
Thanks Ron.

That answers my question. But not as I envisioned it exactly. I must confess I have not been watching the motor building threads. So I know very little on the subject. THe motors would be mechanicaly attatched. Via a gear drive this time. AS I plane to install my airplane motors in an old boat I just got. I noticed you have posted on the following forum so maybe you might have time to post this there. Anyway I got more questions if anyone has time.

My friend asked me about the possibility of mounting multiply Typhoon outrunners on one shaft. So that we could fly bigger planes. As Frits hasn't produced any bigger motors yet. Yes of course I could always get a bigger motor from someone else. Wich leads me to anouther question. What is the benifite of running multiple motors joined together by any means. Is this really any better than just getting a bigger motor. Outside the fact that it looks cool.

Also what do I do about hooking these two controlers to my RX. The RX only has one throttle port. Y-harness? Should I remove one or both power pins?

The followin pic shows where theres room to mount up to three Typhoon 15's. Not that there the right motor for the job but it would look cool!
Aug 02, 2004, 07:05 AM
homo ludens modellisticus
Ron van Sommeren's Avatar
One single motor is more efficient and weighs less.

Use a Y-harness.
When using BEC controllers, you have to remove the power pin (to the receiver) of one of them.

Start badgering Frits about bigger motors

Groeten Ron

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