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Old 04-10-2015, 07:36 PM   #1
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Default 2 pole vs. 4 pole, what's the difference?

Like the title says, new to running pro4 and just want to know the difference between a 2 pole motor and a 4 pole?
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Old 04-10-2015, 07:58 PM   #2
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As the name implies, a 2-pole motor has 2 electromagnets; 1 north and 1 south. A 4-pole motor has 4 eletromagnets; 2 north and 2 south. On a 4-pole motor, the magnets are set up in a north-south-north-south configuration.

Basically, a 2-pole motor is a good RPM motor while a 4-pole motor, having more magnets, will have more torque. You might lose a bit of efficiency with a 4-pole over a 2-pole, but if you’re only running 5/6-minute races that should be ok. You’ll definitely want to look into a 4-pole if you are running the heavier ST or SC trucks.

Also, the gearing might be a little different, too. Try going up a tooth or two with the 4-pole to make up for the loss in RPM that style of motor has.
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Old 04-10-2015, 08:02 PM   #3
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Quote:
Originally Posted by ba4ma View Post
As the name implies, a 2-pole motor has 2 electromagnets; 1 north and 1 south. A 4-pole motor has 4 eletromagnets; 2 north and 2 south. On a 4-pole motor, the magnets are set up in a north-south-north-south configuration.

Basically, a 2-pole motor is a good RPM motor while a 4-pole motor, having more magnets, will have more torque. You might lose a bit of efficiency with a 4-pole over a 2-pole, but if you’re only running 5/6-minute races that should be ok. You’ll definitely want to look into a 4-pole if you are running the heavier ST or SC trucks.

Also, the gearing might be a little different, too. Try going up a tooth or two with the 4-pole to make up for the loss in RPM that style of motor has.
The electromagnets are in the stator of a brushless motor. either wound in a slotted or slot less design. The magnet poles are solid magnets held on the rotor. that may have been what you meant, if so sorry for the correction.

"poles" are the number of magnet poles on the rotor of a brushless motor. 2 pole has a N pole and an S pole (one for each side of the magnet) a 4 pole will have a N, S,N,S pole arrangement.

4 pole motors have more torque, over a conventional 2 pole design. depending on the motor it may be slotted or slotless. by design slotted motors will have more problems with cogging as the magnets seek a certain phase wire. Slot less motors do the same thing, but the operation at low speeds is smoother. You can usually tell the difference because Slot less motors will rotate more freely, versus a slotted motor which may be very "nochy" or hard to turn. I believe that the castle motors are slotted for example.

most people use 540, 545, or 550 4 pole brushless motors in 4x4 act, with the majority being 545 or 550 size motors. 540 only for lighter 4x4 scts. The only 2 pole i would recommend for 4x4 would be the novak ballistic HD, which is 2 pole, but it is very long.

this is all of course for in runner brushless motors. It is the same concept for outrunners (such as those used in multiroters) just inside out.

Last edited by ThePanda; 04-10-2015 at 08:16 PM.
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Old 04-10-2015, 08:05 PM   #4
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Thanks for the info guys!
First time I have heard a good explanation between the two.
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