77,

78.

79.

80,

81.

82,

83.

85.

Rotor rheostatic method of speed control is used for :
(ക) slip ning induction motor (B) squirrel cage induction motor
)6 DC series motor (D) DC shunt motor

What is meant by plugging in the case of a 3-phase induction motor ?
(A) locking of rotor due to harmonics

(8) interchanging two supply phases for quick stopping

(C) starting the motor with direct on line

(ಐ) none of the above

What is the condition for maximum torque under running conditions for a 3-phase induction
motor, if R, is the rotor resistance, X; is the rotor reactance and ‘s’ is the slip ?

1
(^) > = शद © RyG=_ (© ടട (D) Ry=s5%X,

The tarque developed by a single phase induction motor at starting 15 :
(A) more than rated torque (ए) rated torque
(C) less than rated torque (D) 2 0

A reluctance motor is preferable 1೧೯ :
(ക) electric traction (8) timing and control devices
(C) refrigerators (D) lifts and hoists

The phase displacement between starting and running winding of a capacitor start motor is
nearly :
(ക) 90° (8) லு (9 305 12) ௦

Which of the following does not change in a transformer ?
(ಗ) voltage (B) frequency (©) current (D) गर्ज the above

The highest transmission voltage in India is :
(ക) 220 kV (B) 400 kV (ಲ) ۷ (D) 1000 kV

Which of the following transformers has its secondary always kept closed ?
(ക) star-delta transformer (ए) open delta transformer
{C) potential transformer (D) current transformer

117/2014 12 A