Question is ⇒ Which D.C. motor is preferred for elevators ?, Options are ⇒ (A) Shunt motor, (B) Series motor, (C) Differential compoun.d motor, (D) Cumulative compound motor, (E) , Leave your comments or Download question paper.

Question is ⇒ Which D.C. motor is preferred for elevators ?, Options are ⇒ (A) Shunt motor, (B) Series motor, (C) Differential compoun.d motor, (D) Cumulative compound motor, (E) , Leave your comments or Download question paper. Previous question Next question


Q1.	Which D.C. motor is preferred for elevators ?
A.	Shunt motor [Wrong Answer]
B.	Series motor [Wrong Answer]
C.	Differential compoun.d motor [Wrong Answer]
D.	Cumulative compound motor [Correct Answer]
View Answer 14 -15 Explanation:- Answer : D Discuss it below : !! OOPS Login [Click here] is required to post your answer/result Help other students, write article, leave your comments

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Also Read Similar Questions Below :

⇒ For a D.C. shunt motor if the excitation is changed
torque will remain constant
torque will change but power will remain constant
torque and power both will change
torque, power and speed, all will change

⇒ Which of the following loss in a D.C. generator varies significantly with the load current ?
Field copper loss
Windage loss
Armature copper loss
None of the above

⇒ Which of the following can be used for controlling the speed of a D.C. motor ?
Thermistor
Transistor
Thyratron
Thyristor

⇒ Which D.C. motor will be suitable alongwith flywheel for intermittent light and heavy loads?
Series motor
Shunt motor
Cumulatively compounded motor
Differentially compounded motor

⇒ If the terminals of armature of D.C. motor are interchanged, this action will offer following kind of braking
regenerative
plugging
dynamic braking
none of the above

⇒ In a differentially compounded D.C. motor, if shunt field suddenly opens
the motor will first stop and then run in opposite direction as series motor
the motor will work as series motor and run at slow speed in the same direction
the motor will work as series motor and run at high speed in the same direction
the motor will not work and come to stop

⇒ In case the back e.m.f. and the speed of a D.C. motor are doubled, the torque developed by the motor will
remain unchanged
reduce to one-fourth value
increase four folds
be doubled

⇒ During rheostat braking of D.C. series motors
motor is run as a generator
motor is reversed in direction
motor is run at reduced speed

⇒ D.C. series motors are used
where load is constant
where load changes frequently
where constant operating speed is needed
in none of the above situations.

⇒ In a D.C. motor, the ratio Eb/Va indicates
running torque of the motor
starting torque of the motor
efficiency of the motor
speed regulation of the motor

⇒ In a D.C. generator, the iron losses mainly take place in
yoke
commutator
armature conductors
armature rotor

⇒ For which of the following applications a D.C. motor is preferred over an A.C. motor ?
Low speed operation
High speed operation
Variable speed operation
Fixed speed operation

⇒ Which motor should be used for centrifugal pumps ?
Series motor
Shunt motor
Either of the above
None of the above

⇒ Which D.C. motor will be preferred for cónstant speed line shafting ?
Cumulative compound motor
Differentially compound motor
Shunt motor
Series motor

⇒ No-load speed of which of the following motor will be highest ?
Shunt motor
Series motor
Cumulative compound motor
Differentiate compound motor

⇒ The simplest form of a motor controller is
relay
toggle switch
drum switch
magnetic switch

⇒ A wide and very sensitive speed control is usually required in case of
elevators
steel rolling mills
colliery winders
all of the above

⇒ When the electric train is moving down a hill the D.C. motor act as
D.C. series generator
D.C. shunt generator
D.C. shunt motor
D.C. series motor

⇒ If a D.C. motor is to be selected for conveyors, which motor would be preferred ?
Series motor
Shunt motor
Differentially compound motor
Cumulative compound motor

⇒ If B_max is the maximum flux density, then eddy cu rrent loss will vary as
B_max
(B_max)²
(B_max)^1.2
(B_max)^2.4

⇒ Starters are used with D.C. motors because
these motors have high starting torque
these motors are not self-starting
back e.m.f. of these motors is zero initially
to restrict armature current as there is no back e.m.f. while starting

⇒ Sparking at the commutator of a D.C. motor may result in
damage to commutator segments
damage to commutator insulation
increased power consumption
all of the above

⇒ When the armature of a D.C. motor rotates, e.m.f. induced is
self-induced e.m.f.
mutually induced e.m.f.
back e.m.f.
none of the above

⇒ The mechanical power developed by a D.C. motor is equal to
power input + losses
back e.m.f. X armature current
power output X losses
power output X efficiency

⇒ If the speed of a D.C. shunt motor is increased, the back e.m.f. of the motor will
increase
decrease
remain same
become zero

⇒ One D.C. motor drives another D.C. motor. The second D.C. motor when excited and driven
runs as a generator
does not run as a generator
also runs as a motor
comes to stop after sometime

⇒ Regenerative braking on D.C. shunt motors is used when
the load has overhauling characteristics
the load is variable
the load also acts as a braking force
the load is constantly decreasing

⇒ Which method of braking is generally used in elevators ?
Plugging
Regenerative braking
Rheostatic braking
None of the above

⇒ In case of conductively compensated D.C. series motors, the compensating winding is provided
as separately wound unit
in parallel with armature winding
in series with armature winding
in parallel with field winding

⇒ The mechanical power developed by a shunt motor will be maximum when the ratio of back e.m.f. to applied voltage is
4.0
2.0
1.0
0.5