an electric motor operating on a 50v d.c supply draws a current of 12 a if the efficiency of the motor is 30% estimate the resistance of the winding motor.
Efficiency of motor is given by:
Efficiency = Input - losses/ Input
Input power = V*I = 50 * 12 = 600 Watt
Losses = Resistance losses = I2R losses = 122(R)= 144R
0.3 = (600-144R) / 600
180 = 600 -144R
144R= 420
R = 2.91 ohms
Efficiency = Input - losses/ Input
Input power = V*I = 50 * 12 = 600 Watt
Losses = Resistance losses = I2R losses = 122(R)= 144R
0.3 = (600-144R) / 600
180 = 600 -144R
144R= 420
R = 2.91 ohms