What is the approximate efficiency of a 50 HP, 480-volt, 3Ø motor with FLA = 53?

To understand the efficiency of a 50 HP, 480-volt, three-phase motor with a full load amperage (FLA) of 53 amps, we can use the formula for motor efficiency. Motor efficiency can be calculated using the formula:

Efficiency (%) = (Output Power / Input Power) x 100

First, we need to determine the output power. In this case, the output power is 50 HP. To convert horsepower into watts, we can use the conversion factor where 1 HP is approximately 746 watts:

Output Power (in watts) = 50 HP × 746 W/HP = 37,300 watts (or 37.3 kW).

Next, to calculate the input power, we can use the three-phase power formula:

Input Power (in watts) = √3 × Voltage × Current × Power Factor.

Assuming a typical power factor for motors is around 0.9 (this value can vary depending on the motor design and load conditions), we can plug in the values:

Input Power ≈ √3 × 480 V × 53 A × 0.9.

Calculating the above gives us:

Input Power ≈ 1.732 × 480 × 53