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BrianG · 11.15.2007, 02:06 AM

Uh oh, I can see this thread starting to get a little deeper than aqwut probably intended, but good info nonetheless.

Brushless motors aren't really complex all in all. Just about every motor you find in your house (airconditioning/refrigerator compressor motors, washing machine, etc) use a "squirrel cage" motor, which is similar in construction/principle to a 3ph BL motor, except single or dual phase. 3ph motors are generally used in industrial apps where there is a 3ph service.

All our BL motors would spin just fine on straight house A/C, provided it was 3ph and the voltage was a "tad" lower. The issue comes when we want speed control. Can't simply reduce the voltage since that would create tons of heat (operating much like a linear regulator), so you have to either vary the A/C sine wave frequency and/or the DC pulse duty cycle to change the speed. Problem is these aren't the most simple things to make.

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BrianG RC-Monster Admin Offline Posts: 14,609 Join Date: Nov 2005 Location: Des Moines, IA	11.15.2007, 02:06 AM Uh oh, I can see this thread starting to get a little deeper than aqwut probably intended, but good info nonetheless. Brushless motors aren't really complex all in all. Just about every motor you find in your house (airconditioning/refrigerator compressor motors, washing machine, etc) use a "squirrel cage" motor, which is similar in construction/principle to a 3ph BL motor, except single or dual phase. 3ph motors are generally used in industrial apps where there is a 3ph service. All our BL motors would spin just fine on straight house A/C, provided it was 3ph and the voltage was a "tad" lower. The issue comes when we want speed control. Can't simply reduce the voltage since that would create tons of heat (operating much like a linear regulator), so you have to either vary the A/C sine wave frequency and/or the DC pulse duty cycle to change the speed. Problem is these aren't the most simple things to make.