440 V, 77 A, 700 rpm DC separately excited motor having a resistance of 0.11 ohms excited by an external dc voltage source of 24 V. Calculate the torque developed by the motor on full load.(a) 453.51 N-m(b) 451.24 N-m(c) 440.45 N-m(d) 452.64 N-mI have been asked this question in a job interview.My question is based upon Energy Relations During Starting topic in portion Starting of Electric Drives

440 V, 77 A, 700 rpm DC separately excited motor having a resistance o

1.	440 V, 77 A, 700 rpm DC separately excited motor having a resistance of 0.11 ohms excited by an external dc voltage source of 24 V. Calculate the torque developed by the motor on full load.(a) 453.51 N-m(b) 451.24 N-m(c) 440.45 N-m(d) 452.64 N-mI have been asked this question in a job interview.My question is based upon Energy Relations During Starting topic in portion Starting of Electric Drives
Answer» The correct CHOICE is (a) 453.51 N-m To explain: Back emf developed in the motor during the FULL load can be calculated using EQUATION EB = Vt-I×Ra = 431.53V and machine constant Km = Eb÷Wm which is equal to 5.88. Torque can be calculated by using the relation T = Km × I = 5.88×77 = 453.51 N-m.

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