250-V, 50 HP (37.3 kW), DC Shunt Motor has an efficiency of 90 % when running at 1000 rpm on full load. The armature and field resistance are 0.1-ohm and 115-ohm respectively. Find (a) the net and develop torque (b) the startine g resistance to have the line start current equal to 1.5 times the full load current

. A Short Shunt Compound DC Generator supplies 100-amp at 110-volt. Series field resistance  of 0.04-ohm, armature resistance is 0.05-ohm, shunt field resistance of 57- ohm. Iron and  friction losses mount to 852-watts. Find the power input and the over all efficiency.

Q1 Describe the Characteristics, characteristics, efficiency calculations, their applications Of DC Motors in detail

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A 200 V dc shunt motor takes a current of 20A on a certain load. R= 12 and Rah= 2002. Find the resistance to be inserted in series with the armature to reduce the speed to 75% of its original value if the load torque is constant.

A 3 phase , 6 pole , 400 V , 50 Hz , induction motor has R2= 0.1 ohm /ph , X2= 0.8 ohm /ph and the induced emf between slip rings at standstill is 160 V , Assume the friction losses is 300 W. find :- a) the torque output at slip =3% . b) critical slip and the torque maximum .

A 230-V dc shunt motor takes a current of 5A at no-load. The resistance of armature and field circuits are 0.50 ohm and 230 ohm, respectively . If the maximum efficiency occurs at full load current, what is the value of this current? A 14 hp, 240 v shunt motor draws an armature current of 50 A at full-load. The armature resistance including brushes is 0.25 ohm. Calculate the total resistance of a starting box which wound permit this motor to develop a starting torque equal to twice that at full load.

A 230 V DC Shunt motor runs at 700 r.p.m. and takes armature current of 40 A. Find resistance to be added to the field circult to increase speed to 1200 r.p.m. at an armature current of 60 A. Assume flux proportional to field current. Armature resistance = 0.12 n and field winding resistance is 115h

A 240V , Shunt DC - motor delivers power to a load at 1200 Rev / Min . The load Torque drawn by the motor is 320 N.m. The armature %3 resistance is 0.3 Ohm and the field resistance is 100 Ohm and the rotational losses are 500W. a. What are the armature current and the efficiency ? b. If the torque decreased to be 250 N.m find the speed !

Explain the speed-current, torque-current and speed-torque characteristics of dc series motor.