What is the synchronous speed of a 3 phase, 60 Hz, 6 pole motor?

To determine the synchronous speed of a 3-phase motor, one can use the formula:

[

\text{Synchronous Speed (RPM)} = \frac{120 \times \text{Frequency (Hz)}}{\text{Number of Poles}}

]

In this scenario, the frequency provided is 60 Hz and the number of poles is 6. Plugging these values into the formula:

[

\text{Synchronous Speed} = \frac{120 \times 60}{6} = \frac{7200}{6} = 1200 \text{ RPM}

]

This calculation is fundamental to understanding how induction motors operate. The synchronous speed represents the speed of the rotating magnetic field produced by the motor's stator. For a motor with a specific frequency and pole count, the synchronous speed remains consistent and serves as a reference point for the actual operating speed of the motor.

The choices that provide different RPM values either stem from miscalculations or incorrect assumptions about the motor’s specifications. Knowing how to accurately apply the formulas and understanding the underlying principles of motor operation will help in identifying the motor speed appropriate for given electrical and mechanical characteristics.