Question

A 3-phase, Y-connected, 460V, 60Hz, 4-pole induction motor has the full load speed of 1740rpm and the following parameters: R1-0.25ohm; R2-0.2ohm; X1-0.5ohm; X2-0.5ohm; m-30ohm; rotational loss 170ow Determine: a) i. Starting line current when the motor starts directly on full voltage ii. Starting power factor ii. Starting torque b) i. Full load slip ii. Full load line current . Ratio of starting current to full load current iv. Full-load power factor v. Full load torque vi. Efficiency of the motor at full load C) i. Thevenin circuit parameters and the Thevenin voltage ii. Slip at which maximum torque is developed (pull-out slip) ii. Maximum (pull-out) torque D) If this is a wound rotor induction motor with accessible rotor circuit, how much additional resistance should be connected to the rotor circuit if the maximum torque occurs at start?

I just want the answer for part D. So, I will give the answers to the rest of the questions to assist in answering part d of the question.

A) i) 244.2 A (ii) 0.408 lagging (iii) 183.8 Nm B) (i) 0.033 (ii) 42.8A (iii) 5.7 (iv)0.941 lagging (v) 162.8 Nm (vi) 87% C) (i) Rth = 0.24 Xth = 0.49 X2 = 0.5 (ii) 0.196 (iii) 431.2 Nm

Hopefully, these answers will help

Answer 1