Nate Core Practice Test 2026 – Comprehensive Exam Prep

To determine the synchronous speed of an electric motor, you can use the formula:

Synchronous Speed (RPM) = (120 × Frequency) / Number of Poles

In this case, the motor has four poles and is operating at a frequency of 60 Hz. Plugging these values into the formula gives:

Synchronous Speed = (120 × 60) / 4

Calculating that results in:

Synchronous Speed = 7200 / 4 = 1800 RPM

This means that the motor will rotate at a speed of 1800 revolutions per minute when it operates synchronously. Therefore, the correct answer reflects this calculation, confirming that the synchronous speed for a four-pole motor at 60 Hz is indeed 1800 rpm, indicating the motor's theoretical maximum speed under synchronous operation conditions.