A. self-induced e.m.f.
B. mutually induced e.m.f.
C. back e.m.f
D. none of the above
Correct Answer: back e.m.f ✔
Last Updated: July 02, 2018
Related MCQs
- In variable speed motor__________?
- Which method of braking is generally used in elevators ?
- For which types of D.C. motor, dynamic braking is generally used ?
- During rheostat braking of D.C. series motors__________?
- Hopkinson’s test on D.C. machines is conducted at__________?
- Which of the following tests will be suitable for testing two similar D.C. series motors of large capacity ?
- The purpose of retardation test on D.C. shunt machines is to find out__________?
- D.C. generators are installed near the load centres to reduce__________?
- In a D.C. generator, the iron losses mainly take place in__________/
- D.C. generators are normally designed for maximum efficiency around__________?
- The condition for maximum efficiency for a D.C. generator is__________?
- The total losses in a well designed D.C. generator of 10 kW will be nearly__________?
- Which of the following losses are significantly reduced by laminating the core of a D.C. generator ?
- Which of the following loss in a D.C. generator is dissipated in the form of heat?
- Which of the following steps is likely to result in reduction of hysteresis loss in a D.C. generator ?
- In a manual shunt motor starter?
- D.C. shunt motors are used for driving__________?
- Torque developed by a D.C. motor depends upon__________?
- Which of the following loss in a D.C. generator varies significantly with the load current ?
- The losses occurring in a D.C. generator are given below. Which loss is likely to have highest proportion at rated load of the generator ?
- In a D.C. generator all of the following could be the effects of iron losses except__________?
- The hysteresis loss in a D.C. machine least depends on__________?
- Regenerative method of braking is based on that__________?
- The main disadvantage of the Ward-Leonard control method is__________?
- In Ward-Leonard control the lower limit of speed is imposed by________?
- For constant torque drive which speed control method is preferred ?
- Ward-Leonard control is basically a__________?
- Which motor should not be started on no-load ?
- Which of the following motors is most suitable for signalling devices and many kinds of timers ?
- Which of the following motors is usually used in house-hold refrigerators ?
- Why are the D.C. motors preferred for traction applications ?
- If the speed of a D.C. shunt motor is increased, the back e.m.f. of the motor will_________?
- Which of the following motors one will choose to drive the rotary compressor ?
- If the terminals of armature of D.C. motor are interchanged, this action will offer following kind of braking?
- If a D.C. motor designed for 40°C ambient temperature is to be used for 50°C ambient temperature, then the motor__________?
- The armature voltage control of D.C. motor provides__________?
- The plugging gives the__________?
- For a D.C. shunt motor if the excitation is changed__________?
- Which motor has the poorest speed control?
- If I2 be the armature current, then speed of a D.C. shunt motor is__________?
- The speed of a D.C. shunt motor can be increased by__________?
- As there is no back e.m.f. at the instant of starting a D.C. motor, in order to prevent a heavy current from flowing though the armature circuit__________?
- The armature voltage control of D.C. motor provides__________?
- The speed of a motor falls from 1100 r.p.m. at no-load to 1050 r.p.m. at rated load. The speed regulation of the motor is__________?
- Usually wide and sensitive speed control is desired in case of__________?
- Which of the following method of speed control of D.C. machine will offer minimum efficiency ?
- The armature torque of the D.C. shunt motor is proportional to__________?
- As -the load is increased the speed of D.C. shunt motor will__________?
- Which of the following motor has the poorest speed regulation ?
- Buses, trains, trolleys, hoists, cranes require high starting torque and therefore make use of__________?
- In a differentially compounded D.C. motor, if shunt field suddenly opens__________?