MCQs on DC machines
1. The emf induced in a conductor rotating in bipolar field is
- dc
- ac
- dc and ac both
- none of these
2. In an electromagnetic energy conversion device, the developed torque depends upon
- stator field strength and torque angle
- stator field and rotor field strength
- stator field and rotor field strength and torque angle
- stator field strength only
3. In a dc motor, the windage loss is proportional to
- supply voltage
- square of the supply voltage
- square of the flux density
- square of the armature speed
4. Which of the following are the variable losses in a rotating machine?
- core loss and mechanical loss
- core loss and stray load loss
- copper loss and core loss
- copper loss and stray load loss
5. Stray losses are sum of
- iron and mechanical losses
- copper and iron losses
- copper and mechanical loss
- none of these
6. The principle of dynamically induced emf is utilized in
- transformer
- choke
- generator
- thermocouple
7. Which of the following is not a part of dc machine?
- armature
- commutator
- field winding
- damper winding
8. The field coils of a dc generator are usually made of
- mica
- copper
- cast iron
- carbon
9. Laminated yoke in dc motor can reduce
- speed regulation
- iron loss
- temperature rise
- sparking on load
10. Pole shoe of a dc machine is laminated for the purpose of
- decreasing hysteresis loss
- decreasing eddy current loss
- decreasing both hysteresis and eddy current loss
- manufacturing ease
Please ,send the answer because I need answer to correct my result
Click the “correct answer” under each question to see the answer.