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Old 12-31-2002, 02:21 PM   #1
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brushless motors?

BRUSHLESS MOTORS. what makes em so good? how do they work? why are they so expensive? gimme some details. thanks.
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Old 12-31-2002, 07:21 PM   #2
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Hi.Ive asked the same question once....brushless motors are well , without brushes ie. the coms/arms dont have physical contact with the can.so friction is greatly reduced.Im not quite sure how they work but im guessing the arm now is the permanent magnets and the can is the coils,but basically thhey still have the same MO.they are NOT expensive but the ESC's are bcos of ONE thing:it's new.consumer prices will drop once they sell more to recoup the overhead.
Go to http://teamnovak.com for some delicious details of the brushless motors.
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Old 12-31-2002, 08:19 PM   #3
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Originally posted by stoopidbstrd
BRUSHLESS MOTORS. what makes em so good? how do they work? why are they so expensive? gimme some details. thanks.
Brushless technology will be the future of RC Cars. What makes brushless so attractive is the ability of the motor to keep accelerating, the downside to that is it puts a large drain on the batteries. The windings are inside the can with the magnets wound on an arm rotating within the windings, but not touching them. As power is applied to the winding, the magnetic field is generated causing the magnets to rotate. More power applied to the motor, the faster the rotation. Because of no brushes, the can is cooler than regular brushed motors, and also more efficient. The most expensive part is the speed controller that controls the power and monitors the amp draw. Pretty soon we all will go this route as the posibilities of not purchasing brushes and replacement arms is becoming realistic, and cost effective.
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Old 12-31-2002, 10:17 PM   #4
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alright. it's kinda REALLY confusing but thats fine. thanks for the info, but do you guys think i can run a brushless motor with a mech drive?
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Old 01-01-2003, 12:17 AM   #5
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I read about brushless motors I think its the
way to go, check Rum Runner Hobbies
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Old 01-01-2003, 12:41 AM   #6
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Just to confuse u further,brushless motors NEED its own speed controller.it detects and reverses the electricity continuously.this can NEVER be done by ANY other type of speedo.
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Old 01-01-2003, 01:01 AM   #7
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Brushless motors work by using a switching (AC) current, rather than DC. whereas simple brushless motors work easily at a constant speed off normal AC, brushless speed controllers for cars have to be able to quickly sense exactly where the rotor is in it's rotation and switch the current at the appropriate time to keep the motor rotating. This is more difficult with cars because of the huge variation in rpms.

The downsides are a slight delay when hitting the throttle hard out of a slow corner, and the brakes are generally all or nothing, very hard to dial in appropriate braking.

The upside is not having to rebuild your motor every 2 or 3 runs to keep it competitive, and not having to have the latest batteries all the time as contrary to what was written above, they drain your batteries less at the same pace. The good thing is if the track is tight enough, a standard brushed motor can still keep up, so they can actually race side by side on most tracks. The guy with the brushless just doesn't have to have the best batteries and keep rebuilding and replacing his motor.
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Old 01-01-2003, 01:38 AM   #8
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aaahhh. too much information in one sitting. i think i need a drink. thanks guys thats a lot of cool info.
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Old 01-01-2003, 04:06 AM   #9
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check the australian forum for more about brushless
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Old 01-01-2003, 01:34 PM   #10
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How a brushless works. Picture a normal motor. Windings on the armature, magnets on the can, power goes through the brushes and through the windings creating an electro magnet and spins the motor. In a brushless motor, the armature is the magnet and the can is divided into 6 "poles" (a brushed motor has 2). Power is sent to the poles one at a time and creates a spinning magnetic field which in turn spins the armature. Now read on for the difference between sensored systems and non sensored systems.

brushless motors come in two variations. Sensored and non-sensored. In a sensored system (i.e. novak) the speed controller knows where in the rotation the armature is at all times. This allows it to apply power to the correct part of the can for maximum power. In a non-sensored system (i.e. hacker) the speed controller does NOT know where in the rotation the armature is. As a result the speed controller does a series of "checks" (up to six because of the six poles) to find which is the best. This results in the "delay" that sleek mentions. Sensored systems do not have this delay (i have driven the novak at the chicago hobby show so please trust me). I know in the Novak system the brakes are proportional (pull a little on the trigger and it applies a little brake). However, the brakes on a brushless system are so much stronger than on a brushed motor it takes a little more finesse to apply a little (you can also just dial out some end point so max brake is limited).

Hope this helps a little, if you have more questions feel free to IM me at mabman13354420 or email me.
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Old 01-01-2003, 10:43 PM   #11
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wow. thats a lot more complex than i thought. thanks a lot guys, this is really educational.
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Old 01-02-2003, 02:42 AM   #12
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Simple answer. . .

You know on a brushed motor where you have magnets around the outside and brushes that conduct electricity to the winds on the armature? Well, they don't conduct ALL of the electricity, they cause wear and a lot of friction. That can slow a motor and make it less efficient.

With a brushless motor just reverse things - the winds are on the outside and the magnets are on the inside. No brushes to add friction and wear to the comm - since there AINT one. . .also all the power makes it to the winds. . .makes everything MUCH more efficient.

Simple answer!

However, to get a bit more complex - you know that in your brushed motor, there are THREE sets of winds, right? Well, the comm sends power to them in the proper order to make the armature go 'round.

Since there ain't no comm in a brushless motor to send power to the right winds, a special speed control is needed to send power to the winds (on the outside of the motor) - also means that there are THREE wires that go to the motor from the speed control (one to each set of winds) and they match the three parts of the comm. The speed control has to figure out which winds need power to spin the armature and its magnets.

Larger complexity - There are two ways to figure out which winds need power - 1. have a sensored system where the speed control KNOWS where the arm is. 2. Just Do It. Non-sensored.
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Old 01-02-2003, 09:09 PM   #13
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Default I have one

I recently acquired a brushless motor (Lehner 5300) with a Lehner Warrior ESC after experiencing one from a friend. I thought it would be a good practice motor avoiding the trates of the typical motor. My first impression was that this thing is fast and for a motor with no maintenance, you can't beat it. I tried it with an old 4wd off road tamiya car (Top Force) after figuring out all the connections which was really simple after making it hard for myself. I gave it a try here at my local track SoCal R/C raceway. The car ran fast as expected. but after a few laps the car would hesitate to accelerate. Knowing that the ESC might exhibit what they call cogging (a hesitation after a quick throttle) I thought that was the reason. After a quick check-up, I found that one of my rear dogbones was bent and it will not roll smoothly which was the cause of it not accelerating. I took out the ESC and motor and let it run freely and it was smooth as silk so I guess it works fine. I am waiting for my EVO 3 and I will install the brusless in it and see what happens.
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Old 01-02-2003, 10:20 PM   #14
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yo izzy, what do you mean you took out the motor and esc and let it run freely?
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Old 01-02-2003, 11:37 PM   #15
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I think he means he took them out of the car and just ran the motor on his bench (not in a car).
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