Question is ⇒ The coupling angle or load angle of synchronous motor is defined as the angle between the, Options are ⇒ (A) rotor and stator teeth, (B) rotor and the stator poles of opposite polarity, (C) rotor and the stator poles of the same polarity, (D) none of the above, (E) , Leave your comments or Download question paper.

Question is ⇒ The coupling angle or load angle of synchronous motor is defined as the angle between the, Options are ⇒ (A) rotor and stator teeth, (B) rotor and the stator poles of opposite polarity, (C) rotor and the stator poles of the same polarity, (D) none of the above, (E) , Leave your comments or Download question paper. Previous question Next question


Q1.	The coupling angle or load angle of synchronous motor is defined as the angle between the
A.	rotor and stator teeth [Wrong Answer]
B.	rotor and the stator poles of opposite polarity [Correct Answer]
C.	rotor and the stator poles of the same polarity [Wrong Answer]
D.	none of the above [Wrong Answer]
View Answer 7 -4 Explanation:- Answer : B Discuss it below : LiFE CHAnGer Said on 2020-04-23 19:08:08 Jbg !! OOPS Login [Click here] is required to post your answer/result Help other students, write article, leave your comments

Previous question Next question

Also Read Similar Questions Below :

⇒ A synchronous motor develops maximum power when load angle is
45°
60°
90°
120°

⇒ The power factor of a synchronous motor is better than that of induction motor because
stator supply is relieved of responsibility of producing magnetic field
mechanical load on the motor can be adjusted
synchronous motor runs at synchronous speed
synchronous motor has large air gap

⇒ A synchronous motor can develop synchronous torque
when under loaded
while over-excited
only at synchronous speed
below or above synchronous speed

⇒ In a synchronous motor, the armature current has large values for
high excitation only
low excitation only
both high and low excitation
none of the above

⇒ In a synchronous motor, the forced vibrations will be maximum when driving
a reciprocating air compressor
a centrifugal pump
a centrifugal blower
any of the above

⇒ The ratio of starting torque to running torque in a synchronous motor is
zero
one
two
infinity

⇒ A synchronous motor has better power factor as compared to that of an equivalent induction motor. This is mainly because
synchronous motor has no slip
stator supply is not required to produce magnetic field
mechanical load on the rotor remains constant
synchronous motor has large airgap

⇒ If the field winding of an unloaded salient pole synchronous motor is open circuited, the motor will
stop
run as induction motor
function as static condenser
burn with dense smoke

⇒ When load on an over-excited or underexcited synchronous motor is increased, rate of change of its armature current as compared with that of power factor is
more
less
equal
twice

⇒ In a synchronous motor, V-curves represent relation between
armature current and field current
power factor and speed
field current and speed
field current and power factor

⇒ The synchronous motor is not inherently self-starting because
the force required to accelerate the rotor to the synchronous speed in an instant is absent
the starting device to accelerate the rotor to near synchronous speed is absent
a rotating magnetic field does not have enough poles
the rotating magnetic field is produced by only 50 Hz frequency currents

⇒ The back e.m.f. of a synchronous motor depends on
speed
load
load angle
all of the above

⇒ When the excitation of an unloaded salient pole synchronous motor suddenly gets disconnected
the motor stops
it runs as a reluctance motor at the same speed
it runs as a reluctance motor at a lower speed
none of the above

⇒ A synchronous motor can be made selfstarting by providing
damper winding on rotor poles
damper winding on stator
damper winding on stator as well as rotor poles
none of the above

⇒ Change of D.C. excitation of a synchronous motor changes
applied voltage of the motor
motor speed
power factor of power drawn by the motor
any of the above

⇒ Synchronous motor always runs at
the synchronous speed
less than synchronous speed
more than synchronous speed
none of the above

⇒ Stability of a synchronous machine
decreases with increase in its excitation
increases with increase in its excitation
remains unaffected with increase in excitation
any of the above

⇒ A synchronous motor will always stop when
supply voltage fluctuates
load in motor varies
excitation winding gets disconnected
supply voltage frequency changes

⇒ When the field of a synchronous motor is under-excited, the power factor will be
leading
lagging
unity
zero

⇒ In a synchronous motor, damper windings are provided on
stator frame
rotor shaft
pole faces
none of the above

⇒ Exciters of synchronous machines are
d.c. shunt machines
d.c. series machines
d.c. compound machines
any of the above

⇒ In a synchronous motor it the back e.m.f. generated in the armature at noload is approximately equal to the applied voltage, then
the motor is said to be fully loaded
the torque generated is maximum
the excitation is said to be zero per cent
the excitation is said to be hundred per cent

⇒ In which of the following motors the stator and rotor magnetic field rotate at the same speed ?
Universal motor
Synchronous motor
Induction motor
Reluctance motor

⇒ While starting a salient pole synchronous motor by induction motor action and connecting field discharge resistance across field, starting and accelerting torque is produced by
induction motor torque in field winding
induction motor torque in damper winding
eddy current and hysteresis' torque in pole faces
reluctance motor torque due to saliency of the rotor

⇒ The operating speed of a synchtunous motor can be changed to new fixed value by
changing the load
changing the supply voltage
changing frequency
using brakes

⇒ When the stator windings are connected in such a fashion that the number of poles are made half, the speed of the rotor of a synchronous motor
remains same as the original value
decreases to half the original value
tends to becomes zero
increases to two times the original value

⇒ A synchronous motor can operate at
lagging power factor only
leading power factor only
unity power factor only
lagging, leading and unity power factors

⇒ If in a synchronous motor, driving mechanical load and drawing current at lagging power factor from constant voltage supply, its field excita.6.on is increased, then its power factor
become more
become less
remain constant
none of the above

⇒ The efficiency of a properly designed synchronous motor will usually fall in range
60 to 70%
75 to 80%
85 to 95%
99 to 99.5%

⇒ Dust and dirt accumulation on motor winding will result in
rise in winding temperature
increased core losses
shorting of coils
eddy current flow

Jbg