Induction Motor: Full Load Shaft Torque, Input Power, and Number of Poles Calculation

26 May 2023

Question:

How can we calculate the full load shaft torque, input power, and number of poles of a 60 hp, 50 Hz, 500 V, Y-connected, 2960 rpm Induction motor?

To calculate the full load shaft torque, input power, and number of poles of the given induction motor, we can use the following formulas:

Full Load Shaft Torque (T): T = (P × 5252) / N

Input Power (P): P = (V × I × √3) / 1000

Number of Poles (P): N = (120 × f) / P

Given information:

Power (P) = 60 hp

Frequency (f) = 50 Hz

Voltage (V) = 500 V

Speed (N) = 2960 rpm

Let's calculate each value:

Full Load Shaft Torque (T): T = (60 × 5252) / 2960 = 106.22 lb-ft

Input Power (P): P = (500 × I × √3) / 1000

Number of Poles (P): N = (120 × 50) / P

Therefore, the full load shaft torque is 106.22 lb-ft, the input power depends on the current (I), and the number of poles depends on the value of P.