AC Motor rpm (Speed)

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The motor speed will be indicated as rpm. This will be the rated speed for the motor, and it won't account for slip. The actual speed of the motor will be less because of slip. The speed of the motor is determined by the number of poles and the frequency of the AC voltage.

Typical speed for a two-pole motor is 3600 rpm, a four-pole motor is 1800, and an eight-pole motor is 1200. The actual speed of the motor rated for 3600 rpm will be approximately 3450, for the 1800 rpm motor it will be approximately 1750, and for the 1200 rpm motor it will be approximately 1150. The actual amount of slip will be indicated by the motor design letter.

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