1. The normal value of the armature resistance of a D.C motor is
- 0.005
- 0.5
- 10
- 100
Answer: 2
2. The Eb/V Ratio of a D.C motor is an indication of its
- Efficiency
- Speed regulation
- Starting torque
- Running torque
Answer: 1
3. The mechanical power developed by the armature of a D.C. motor is equal to
- Armature current multiplied by back e.m.f.
- Power input minus losses
- Power output multiplied by efficiency
- Power output plus iron losses
Answer: 1
4. The induced e.m.f .in the armature conductors of a D.C. motor is
- Sinusoidal
- Trapezoidal
- Rectangular
- alternating
Answer: 1
5. D.C motor can be looked upon as D.C. generator with the power flow
- Reduced
- Reversed
- Increased
- Modified
Answer: 2
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6. In a D.C. motor, the mechanical output power actually comes from.
- Field system
- Air- gap flux
- Back e.m.f.
- Electrical input power
Answer: 4
7. The maximum torque of D.C. motor is limited by
- Commutation
- Heating
- Speed
- Armature current
Answer: 1
8. which of the following quantity maintains the same direction whether D.C. machine runs as a generator or as a motor?
- Induced e.m.f
- Armature current
- Field current
- supply current
Answer: 1
9. Under constant load conditions, the speed of a D.C. motor is affected by
- Field flux
- Armature current
- Back e.m.f.
- Both (b) and(c)
Answer: 1
10. It is possible to increases the field flux and, at the same time, increase the speed of a D.C. Motor provided its- is held constant
- Applied voltage
- Torque
- Armature circuit resistance
- Armature current
Answer: 4
11. The current drawn by a 120-v D.C Motor of armature resistance 0.5 ohm and back e.m.f 110 V is ________ amperer
- 20
- 240
- 220
- 5
Answer: 1
12. The shaft torque of D.C. motor is less than its armature torque because of _________________ losses
- Copper
- Mechanical
- Iron
- rotational
Answer: 4
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