In case of D.C. shunt motors the speed is dependent on back e.m.f. only because flux is practically constant in D:C. shunt motors.
Answer : The mechanical power developed by a shunt motor will be maximum when the ratio of back e.m.f. to applied voltage is 0.5.
Answer : If the speed of a D.C. shunt motor is increased, the back e.m.f. of the motor will increase.
Answer : The armature may burn if the back e.m.f. of a D.C. motor vanishes suddenly.
Description : Do AC induction motors have back EMF?
Answer : In D.C. shunt motors as load is reduced the speed will remain almost constant.