RC Electric Off-Road Trucks, Buggies, Truggies and more Discuss electric RC off-road, buggies & trucks here. Also discuss brushless motors, speed controllers aka ESC's, brushed motors, etc

dual brushless motor, one controller?

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Old 09-24-2006, 08:34 PM
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Default dual brushless motor, one controller?

Can 1 controller be used to control multiple brushless motors as long as the current capacity is not exceeded?

If so are there any other concerns (especially if they are geared together?)
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Old 09-24-2006, 09:14 PM
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Default RE: dual brushless motor, one controller?

The general rule is a resounding NO. But if the manufacturers perfectly matches the motors then it can happen. In theory anyway. I do know that there is a company working on a duel set up. But it is going to be very pricy. It will be cheaper to get 2 set ups.
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Old 09-24-2006, 09:22 PM
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Default RE: dual brushless motor, one controller?

What's the point? If the motor isn't powerful enough, just buy a stronger one instead.
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Old 09-24-2006, 09:28 PM
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Default RE: dual brushless motor, one controller?

Some chassis require 2 motors and for some installs a dual may be easier to mount up, OK the question now becomes

Why cannot 1 controller run 2 or more motors?
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Old 09-24-2006, 09:43 PM
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Default RE: dual brushless motor, one controller?

As I understand it...
The gauss on both motors has to be within 1.21 %
There has to be a critical matching of thewindings to get exactly the same rpm otherwise the motors fight each other.
The timing has to be exactly matched or one will be stronger than the other and they will fight.
the controller better be one hell of a controller. You just doubbled the stress on the system.

The smart thing it to run one unless you are running each front and rear seperately. Then get 2 set ups. Dont forget to hook up one motor for reverse.
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Old 09-24-2006, 09:58 PM
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Default RE: dual brushless motor, one controller?

I'm thinking that 2 seperate motors with one controller would be ok as long as the esc was (twice as big) capable of the current. Or for that matter any number of seperate motors can be run off of a single esc. as long as the current was not exceeded.
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Old 09-24-2006, 10:20 PM
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Default RE: dual brushless motor, one controller?

Like I said the word is a resounding NO. This is not a thing to do. Look I know many things about BL systems and people that have a much greater knowledge than I have told me not to do this. I am talking to the guys that design the motors and controllers. There is one company working on a system. They contacted me about a week ago.. They want me to run it through its paces. It is very expensive. It is designed for very large scale aircraft. I will not get it for about 3 weeks. If allowed I will post some things on it. Shawn Palmer tried this and it worked for a little while (on a MLST) then the smoke got out of the wire, so to speak.

If you want to go ahead. Everyone I know tells me this is a bad idea.

I just realized that I did not mention the most important problme why it is not adviseable. When you start a brushless motor from dead stopped. The windings must be excited in a very spicific order for it to move in the correct direction. If one gets one and the other is not in perfect sync the 2 will ...... lets just say all hell breaks loose.
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Old 09-24-2006, 10:29 PM
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Default RE: dual brushless motor, one controller?

Ok, I think I get it, it has to do with the timing and the way brushless interacts with its motor. So even if the two motors were seperate it may not work. I have to think about this to let it sink in. []
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Old 09-24-2006, 10:36 PM
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Default RE: dual brushless motor, one controller?

I'm think of this and if we had a single set-up, without feedback from the motor to the esc (if that's sensorless) then the esc has no idea where the motor is turned and therefore must determine the position of the motor. If this is true then why is it not possible to have two seperate motors and allow the esc to simply run them both.

I don't know much about brushless, but can only see a problem if the two motors happened to be geared together (at the wrong position) would give bad results.

If the two motors were not hooked together would the differing speeds and distances travelled by each motor in the same vehicle cause the two to constanly want to go out of sync?
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Old 09-25-2006, 12:37 AM
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Default RE: dual brushless motor, one controller?

The programming in the controller uses "fly back voltage" to determine what lead to excite first. So the sensorless dose the same thing as the sensored but without the extra parts and limitations of sensored.
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Old 09-25-2006, 11:23 AM
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Default RE: dual brushless motor, one controller?

Oh, gotcha, thanks.
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Old 09-25-2006, 04:05 PM
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Default RE: dual brushless motor, one controller?

Well, me and my bro, when we sometimes talk crazy talk to pass time, sometimes chat about crazy setups. One of the popular ones I keep bringing back up, is hooking up two C4 9800 (is that right?) KV systems in an 18t.

We'd use two separate controllers, using a y-connector to goto one reciever. We'd hook up the batteries, w/e batteries they may be, in series, or parallel, depending on our desire for runtime or speed, but at the same time not exceeding the esc amp rate and currents.

I would get into more detail on how we would set it up, but I really don't feel like typing it all out. My brother has (some how) all this knowledge about these things, that if we had the money, and the guts to experiment it, we would do it in a heart beat!

Haha, perhaps something of tomorrow!
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Old 09-25-2006, 08:34 PM
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Default RE: dual brushless motor, one controller?

What if you got two sensored motors, wired them together, geared them together so the rotors and cans are in the same position relative to each other, and only plugged one sensor harness into the esc? Shouldnt that technically work?
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Old 09-25-2006, 09:02 PM
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Default RE: dual brushless motor, one controller?

Give them a common output shaft. common not just hooked to the same gear it must be one continous piece of metel, than it would work i presume. I will ponder that more. But right now I say that would work.
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Old 09-26-2006, 02:24 AM
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Default RE: dual brushless motor, one controller?

I think that 2 sensorless motors should work as long as they were in the same position and stayed that way. An e-maxx may be a culprit for a test.
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Old 09-26-2006, 06:28 AM
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Default RE: dual brushless motor, one controller?

u-dud-
It would be the same as I stated. You will need a one piece shaft. So there is no way they came out of 'time'. I am still pondering this. I am still not 100% that it would be flawless. It looks ok on a ruff look over but I will 'do the math' today to be sure.
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Old 09-26-2006, 06:43 PM
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Default RE: dual brushless motor, one controller?

Hacker already has a quad "C50" motor setup but they don't have a controller to handle it apparently

http://www.hackerbrushless.com/motors_c50quad.shtml
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Old 09-26-2006, 08:14 PM
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Default RE: dual brushless motor, one controller?

[X(]......Crazy......
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Old 09-27-2006, 06:45 PM
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Default RE: dual brushless motor, one controller?

I'm terrified.
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Old 09-27-2006, 07:25 PM
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Default RE: dual brushless motor, one controller?

Quote:
ORIGINAL: U-dUd

I'm thinking that 2 seperate motors with one controller would be ok as long as the esc was (twice as big) capable of the current. Or for that matter any number of seperate motors can be run off of a single esc. as long as the current was not exceeded.
if you were using a brushed system, then yeah it works that way, but brushless is different... people need to get used to it...

in vehicles like the mini lst where the twin motors are spinning the same spur gear, if you line the motors up so that the magnets in them are parallel when you install them onto the truck,then yeah it could work... i imagine that the quad motor thingie would also work the same way,seeing that it comes with its own gearbox for all the motors to spin the same output shaft, so all the alignment is already done for you in the factory all you do is plug and play...

its impossible to make perfectly identical motors, but for you shouldnt need perfectly identical motors for a brushless system , just like you dont need perfectly identical motors for your brushed system , like when one motor was having slightly more/less torque/top end than the other it still worked properly, they didnt fight each other or anything
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