What is the full-load current of a 230 volt, 5 hp motor?

To determine the full-load current of a motor, one can use the formula that relates horsepower (hp), voltage (V), and current (I). Specifically, for a 230-volt motor, the formula is:

I = (hp × 746) / V

Where:

• 746 is the number of watts per horsepower

• hp is the horsepower rating of the motor

• V is the voltage.

In this case, for a 5 hp motor:

I = (5 hp × 746) / 230 V

I = 3730 / 230

I ≈ 16.22 amps

This result, however, does not match any of the options provided; thus, it signifies the need to consider the motor's efficiency and power factor, which are crucial when calculating full-load current for AC motors.

Typically, full-load currents for motors are also adjusted based on standard values derived from NEC (National Electric Code) tables, which account for common ratings and efficiency:

For a 5 hp, 230-volt motor, the typical full-load current is approximately 28 amps. The value of 28 amps falls squarely within the common current ratings associated with this size motor, thus justifying this selection as