If I2 be the armature current then speed of a D.C. shunt motor is
independent of Ia
varies as la
varies as (Ia)
proportional to la
independent of Ia
Following motor is used where high starting torque and wide speed range control is required.
D.C. motor
Induction motor
Single phase capacitor start
Synchronous motor
D.C. motor
The speed of a D.C. motor can be varied by varying
resistance in series with armature
any of the above
field current
applied voltage
any of the above
If a D.C. motor designed for 40°C ambient temperature is to be used for 50°C ambient temperature then the motor
is to be derated by a factor recommended by manufacturer and select the next higher H.P. motor
of lower H.P. should be selected
of higher H.P. should be selected
can be used for 50°C ambient temperature also
is to be derated by a factor recommended by manufacturer and select the next higher H.P. motor
If the terminals of armature of D.C. motor are interchanged this action will offer following kind of braking
none of the above
dynamic braking
regenerative
plugging
plugging
Which of the following motors is most suitable for signalling devices and many kinds of timers ?
D.C. shunt motor
D.C. series motor
Reluctance motor
Induction motor
Reluctance motor
Which motor should not be started on no-load ?
Series motor
Differentially compounded motor.
Cumulatively compounded motor
Shunt motor
Series motor
Why are the D.C. motors preferred for traction applications ?
The speed is inversely proportional to the torque and the torque is proportional to square of armature current
Torque is proportional to armature current
Torque and speed are inversely proportional to armature current
Torque is proportional to square root of armature current
The speed is inversely proportional to the torque and the torque is proportional to square of armature current
Ward-Leonard control is basically a
armature resistance control method
voltage control method
field diverter method
field control method
voltage control method
For constant torque drive which speed control method is preferred ?
Armature voltage control
Field control
Shunt armature control
Mechanical loading system
Armature voltage control
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