- 134 Fundamentals Of Electrical Drives Braking Operation 5 9 State And Explain The Important Features Of Various Braking 1 (76.92 KiB) Viewed 24 times
134 Fundamentals of Electrical Drives Braking Operation 5.9 State and explain the important features of various braking methods of dc motors. 5.10 A 230 V, 870 rpm, 100 A separately excited de motor has an armature resistance of 0.05 2. It is civile to an overhauling load with a torque of 400 N-m. Determine the speed at which motor can hold the last by regenerative braking. 5.11 A 230 V, 960 rpm and 200 A de separately excited motor has an armature resistance of 0.02 Q. It's driving an overhauling load whose torque may vary from zero to rated motor torque. Field flux can be changed and field saturates at 1.2 times the rated flux. Calculate speed range in which motor can talk the load by regenerative braking without exceeding twice the rated motor current. 5.12 Motor of Problem 5.11 is now required to hold the rated load torque by dynamic braking at 1200 per without emf exceeding 230 V. Calculate the value of external resistance to be connected across wmature 5.13 A 220 V, 100 A, dc series motor has armature and field resistances of 0.04 and 0.06 2 respectives Running on test on no load as a separately excited generator at 1000 rpm it gave following results 25 50 Field current, A 75 100 125 66.5 124 158.5 181 198.5 Terminal voltage. V 211 Machine is connected for dynamic braking with a braking resistances of 1.5.2. Calculate motor current 150