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Old 04-26-2003, 11:07 AM   #1
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Default Brushless Motors :: Explain!

What are brushless motors and how do they differ from normal electric motors? I am getting a Team Losi Triple-XT and does that come with a brushless? Would I get more speed with a brushless? I haven't heard much about this, so some good companies would be appreciated too! Thanks!
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Old 04-26-2003, 12:29 PM   #2
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a brushless motor dose not use the brushes that a normal motor would have. try thinking of this motor as an inside out motor, as the windings are around the can and not on the arm which spins. the advantage of a brushless motor is that since the windings are not on the arm the motor can acceleration, and no brushes to replace and you dont have to true the com ie. less maintanice (sp?) as far as performance. ive only seen the novak super sport system in a xxx4 and it was as fast as a brushed motor powerd cars on the track as well. novak says its like a 10 turn motor but i think there are like 6 diffrent profiles on the speed controle so you can change the motors performance from stock to mod i think? as for your question on dose the losi xxxt come with one- unless your getting a rtr you have to put your own electronics in. and a rtr comes with a brushed motor (19 turn i think) and all the electronics installed. hope this helps
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Old 04-26-2003, 02:19 PM   #3
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No kit or rtr will come with a brushless (but maybe in the future). yes they will make your car go alot faster and if you get the novak... NO MATINANCE! and you save alot of money by not having to buy brushes.
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Old 04-26-2003, 05:51 PM   #4
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Maybe in like 4 or 5 years they will come with RTR. A brushless motor cost about 280 with a ESC. you have to have a special ESC to run it.
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Old 04-26-2003, 10:04 PM   #5
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Here's a quick summary of the differences between a brushed and brushless motor.

Brushless motors:

* Have no brushes or comms - the only parts that can wear are the bearings. So brushless motors require almost no maintenance.

* The windings are on the can and do not move, vs. on the arm for a brushed motor. This allows a brushless motor to run much cooler because it is much easier to dissipate heat - it's like connecting the windings to a big heat sink (the can).

* The 'commutation' or switching of current in the windings is done by the speed control instead of by the brushes and comm. This makes the speed control much more complicated.

* Brushless motors are typically about 20% more efficient than a brushed motor, and are more efficient across a much wider power range than a brushed motor.

* A brushless setup is more expensive up-front, but it is cheaper in the long run because of the minimal maintenance required. Much cheaper when you factor in the cost of such things as a motor lathe, brush serrator, etc.

* Prices for a brushless motor setup (motor and controller) start at about $240 and go up from there. You can easily spend $500 on a system for an E-Maxx, for example.
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Old 04-26-2003, 10:30 PM   #6
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and the other good thing about brushless is yu dont need a comm lathe or replace the brushes a lot.
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Old 04-27-2003, 06:10 AM   #7
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Most kits that come with a motor or rtrs have motors that you cannot see the brushes, that does not mean it is brushless. They have thier brushes inside the can.
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Old 04-29-2003, 04:46 PM   #8
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I read in Xtreme RC Cars today that a 10-turn brushed motor performs better than the Novak setup.
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Old 04-30-2003, 03:21 PM   #9
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I can't wait until the prices go down on the brushless then I bet they will be out of stock
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Old 05-01-2003, 02:37 PM   #10
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i would say the novak sport system is slightly better than a hot stock motor, nothing close to a 10turn... Maybe a 16 or 17turn motor at zero degrees at best, anyways...

I have a question. Do brushless motors run on DC or AC?

later
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Old 05-01-2003, 04:43 PM   #11
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Quote:
Originally posted by synapse79

I have a question. Do brushless motors run on DC or AC?
Well, it starts to get a little sticky depending on how you define it, but basically I think the answer to your question is essentially AC, using the term rather loosely.

A regular brushed motor is clearly DC. At full throttle the controller just feeds a steady voltage to the motor. To run slower, the controller turns that DC voltage on and off - the more on vs. off, the faster it goes.

A brushless motor is a whole 'nother matter. I don't know exactly how it works, but the controller essentially 'turns on' one pair of the three power wires at any given time. I believe it also uses all combinations of 2 wires out of three, depending on which wind it wants to excite, which depends on where in the rotation the rotor is located.

So each pair is excited once each revolution, I think. So the controller has to switch the power on and off to each pair pretty rapidly. At 25000 RPM, the controller would have to switch something like 75000 times. That's a whole lot faster than a brushed controller would be switching at any speed. This is probably the key reason why the Novak controller gets so hot - switching consumes power.

And this brings up the real trick of brushless motors - the controller needs to know where the rotor is in order to know which wind to fire. That's why the Novak has sensors - they detect the location of the rotor. This also explains cogging - if the controller is a little confused about where the rotor is located, then it could fire the wrong wind and the motor will not run very smoothly, which is cogging. The older generation of brushless motors even occasionally started off the line going backwards because the controller wasn't sure where the rotor is. All the new generation brushless controllers seem to have this pretty well figured out, even the sensorless ones.

I may be a little off on the details, but I believe this should give a basic idea of what's going on with a brushless motor.
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Old 05-01-2003, 04:45 PM   #12
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Almost forgot about this nice animation that shows kinda how a brushless works:

http://www.servomag.com/flash/2-pole...ldc-motor.html
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Old 05-01-2003, 04:57 PM   #13
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so essentually the esc varies the frequency of the alternating current, (and maybe the voltage as well) to vary the speed of the motor?
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Old 05-01-2003, 05:42 PM   #14
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I believe so, yes. Although I don't think it varies the voltage as in a true AC motor. I think the voltage is either positive, negative or zero - as shown in the animation.
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Old 05-01-2003, 07:05 PM   #15
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Default ahhhh, then you guys should try sensorless escs

Salutations Earthlings!
i am currently using a Schulze 58CE brushless esc, which is a sensorless esc.with a LMT 3100 sensorless motor.
unlike sensored setups like the novak, sensorless systems use back EMF to determine where the rotoris and also which direction it'll be turning. sensorless ESCs can be used with sensored motors but sensored ESCs CANNOT be used with sensorless motors.
as there are no sensored info for the esc to process, the sensorless ESCs tend to be more efficient and faster.
thats why if you compare novak's brushless system with team orion's, TO is able to offer a wider selection of motors whereas novaks is limited to that one motor slaved to the esc.
more parts in your motor means more potential for failure.
although it seems that TO has yet to release their range of mototrs, you can easily mate TO's esc with ANY brushless motor on the market including novak's.
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