What would be the cycles of a four-pole motor rated at 150 hp, 120 volts, running at 1,800 rpm's?

What would be the cycles of a four-pole motor rated at 150 hp, 120 volts, running at 1,800 rpm's?

• A. 30 cycles
• B. 60 cycles
• C. 120 cycles
• D. 180 cycles

Answer: (B)

The cycles of a motor, commonly referred to as the frequency in hertz (Hz), can be determined using the relationship between the number of poles, speed, and frequency. For a synchronous motor, the synchronous speed in revolutions per minute (RPM) can be calculated using the formula: \[ \text{Synchronous Speed (RPM)} = \frac{120 \times \text{Frequency (Hz)}}{\text{Number of Poles}} \] In this case, the motor has four poles and is running at 1,800 RPM. To find the frequency, we can rearrange the formula: \[ \text{Frequency (Hz)} = \frac{\text{Synchronous Speed (RPM)} \times \text{Number of Poles}}{120} \] Substituting the known values into the equation: \[ \text{Frequency (Hz)} = \frac{1800 \times 4}{120} \] Calculating this gives: \[ \text{Frequency (Hz)} = \frac{7200}{120} = 60 \, \text{Hz} \] Thus, the cycles of the four-pole motor run at 60 cycles per second or 60 Hz. This aligns perfectly

The cycles of a motor, commonly referred to as the frequency in hertz (Hz), can be determined using the relationship between the number of poles, speed, and frequency. For a synchronous motor, the synchronous speed in revolutions per minute (RPM) can be calculated using the formula:

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

In this case, the motor has four poles and is running at 1,800 RPM. To find the frequency, we can rearrange the formula:

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

Substituting the known values into the equation:

[ \text{Frequency (Hz)} = \frac{1800 \times 4}{120} ]

Calculating this gives:

[ \text{Frequency (Hz)} = \frac{7200}{120} = 60 , \text{Hz} ]

Thus, the cycles of the four-pole motor run at 60 cycles per second or 60 Hz. This aligns perfectly