Question68:-In illumination space to height ratio is
&:-1#2 2
8:-1
C:-less than 1
D:-None of the above
Correct Answer:- Option-A
Question69:-The induction motor cannot run at synchronous speed because if so
A:-Rotor emf would be zero
B:-Rotor current would be zero
C:-Rotor torque would be zero
D:-All the above
Correct Answer:- Option-D
Question70:-Semi closed or totally closed slots are used in 3@ Induction Motor essentially ‏دا‎
‎A:-Reduce magnetizing current
B:-Increase efficiency
C:-Improve starting torque
D:-Increase magnetizing current
Correct Answer:- Option-A
Question71:-In DC machine the armature windings are placed on the rotor for effective
A:-Generation of voltage
B:-Development of torque
C:-Commutation
D:-Energy conversion
Correct Answer:- Option-C
Question72:-The most powerful electromagnet in a normal DC machine operating at full load condition is
A:-Field winding
B:-Armature winding
C:-inter pole winding
D:-Compensating winding
Correct Answer:- Option-A
Question73:-Which of the following is called as stray flux
A:-Armature flux
ield flux
C:-Leakage flux
D:-None of the above
Correct Answer:- Option-C
Question74:-When a coil moves through a time varying flux the induced emf present in the coil is
A:-Dynamically induced
B:-Statically induced
C:-Motional emf
D:-Both dynamically and Statically induced
Correct Answer:- Option-D
Question75:-A 3 & SCIM stator rewound for 6 poles withh out any alteration in the rotor will run at a speed
A:-<1000 rpm
B:-<1500 rpm
C:-<1200 rpm
D:-0 rpm
Correct Answer:- Option-A
Question76:-A 30 star connected IM takes 20A from supply. When connected in delta the motor will take a current of
2:-20%3 &
B:-20/V3 A
C:-20A
D:-10A
Correct Answer:- Option-A
Question77:-The amature core of a DC machine is laminated to minimise
A:-Hysteresis loss
B:-Eddy current loss
C:-Mechanical loss
D:-Temperature loss