Single Phase Motors Part 4
Single Phase Motors Part Four (Fill In The Blank)
1. In capacitor motors, the capacitor is connected in ………………….. with the starting winding.
Answer: series
2. In ceiling fans generally …………………. motors are used
Answer: capacitor
3. In shaded pole motors the shading coil is normally made of ……………….
Answer: copper
Single Phase Motors Part 4
4. A universal motor has …………………. starting torque.
Answer: high
5. The capacitor used on ceiling fans has capacitance of few …………………. farads.
Answer: micro
6. A shaded pole type motor is generally not used because it has poor …………………
Answer: starting torque
7. For high speed and high starting torque ………………….. motor is preferred.
Answer: universal
8. Single phase motors are generally fitted with …………………… bearings.
Answer: ball
Single Phase Motors Part 4
9. The running winding of a split phase induction motor has ……………… resistance and ……………………. reactance.
Answer: low, high
10. A capacitor motor has ………………….. starting torque than equally rated slip phase induction motor.
Answer: higher
11. The starting torque and current taken by a repulsion motor depends on the …………………….. .
Answer: brush position
12. The advantage of repulsion motor over other single phase motors is ……………………………
Answer: high efficiency
Single Phase Motors Part 4
13. For applications demanding high speed of the order of 5000. rpm, a ………………………. motor is suitable.
Answer: universal
14. For recorded players a …………………. motor is suitable.
Answer: hysteresis
15. The single phase motor suitable for signal devices is …………………. motor.
Answer: reluctance
16. The rotor of a hysteresis motor is made of a material having high ……………………. and …………………………
Answer: hysteresis loss, retentivity
17. n case of hysteresis motors the power factor is ……………….:…….
Answer: low
Single Phase Motors Part 4
18. If 8 micro F capacitor is used on 200 W capacitor motor, the value of capacitor to be used on 600 W capacitor will be …………………………
Answer: 20 μF
19. The ………………………. motor has unsymmetrical rotor.
Answer: reluctance
20. Any motor may become hot when subjected to ……………………….
Answer: overload
21. The power factor of an ac series motor can be improved by ……………………… the inductance of field and armature
winding.
Answer; decreasing
22. The starting torque of a capacitor motor is …………………………..
Answer: low
Single Phase Motors Part 4
23. In electric clocks …………………………… motor is used.
Answer: synchronous
24. Only …………………………… motor is capable of running on ac as well as dc.
Answer: universal
25. The speed-torque characteristics of a repulsion induction motor resemble to that of dc ……………………………… motor.
Answer: compound
26. A shaded pole motor has …………………………. initial cost and ……………………… maintenance cost.
Answer: low, low
27. Commutator, capacitor and centrifugal switch are not provided in case of …………………….. motor.
Answer: shaded pole
Single Phase Motors Part 4
28. Power to weight ratio is highest in case of ……………………. motor.
Answer: universal
29. The stator of a shaded pole motor resembles that of …………………………. motor.
Answer: hysteresis
30. In shaded pole motors the direction of rotation is from …………………….. pole to ………………………… pole.
Answer: main, shaded
31. A 22 gauge wire will be ………………………… as compared to a 20 gauge wire.
Answer: thinner
Single Phase Motors Part 4
32. AC series motors of a large size are used in ……………………………
Answer: railway locomotives
33. Most of the single phase motors are designed to run in ……………………… horse power range.
Answer: fractional
34. In capacitor motors, the current is in ……………………… with that in the main winding.
Answer: quadrature
35. An amplidyne is a …………………………. field machine.
Answer: cross
36. The rotor of a ……………………………. motor has no protrusions, teeth or windings.
Answer: hysteresis
37. The rotor of a hysteresis motor must be of ……………………… material.
Answer: magnetic
Single Phase Motors Part 4
38. The rotating magnetic field in a hysteresis motor magnetizes the metal of the rotor and induces ……………………………. within it.
Answer: poles
39. In a hysteresis motor when the motor reaches synchronous speed, the stator flux ceases to sweep across the rotor and the rotor acts like a ……………………………..
Answer: permanent magnet
40. The characteristics of a universal motor resembles that of dc …………………………. motor.
Answer: series
41. Table fan motor ratings arc usually less than …………………………. watts.
Answer: 100
42. A pistol drill is usually fitted with a ………………………….. motor.
Answer: universal
Single Phase Motors Part 4
43. Gear trains are often used in ……………………………….. motors to obtain operating speeds.
Answer: universal
44. Ball bearings offer less friction as compared to …………………………… bearings.
Answer: bush
45. The rotor shaft of a universal motor is made of………………………….
Answer: mild steel
46. The direction of rotation of the reluctance start motor is always from the……………………………… air gap to the
……………………………… air gap.
Answer: wide, narrow
Single Phase Motors Part 4
47. Hysteresis motors are made in low horse power range usually below ……………………………….. H.P.
Answer: 1/100
48. For the same load a dc series motor will have ………………………… speed as compared to a dc shunt motor.
Answer: higher
49. Electronic speed controllers for single phase motors use …………………. and ……………………………
Answer: diacs, triacs
50. A reluctance motor will operate as sub-synchronous reluctance motor when the number of salient poles on the rotor is …………………………….. than the number of electrical poles on the stator.
Answer: great
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Single Phase Motors Part 4
