Q.1
D.C. generators are normally designed for maximum efficiency around
Q.2
Three point starter can be used for
Q.3
These days D.C. motors are widely used in
Q.4
In D.C. shunt motors as load is reduced
Q.5
What will happen if the back e.m.f. of a D.C. motor vanishes suddenly?
Q.6
If a D.C. shunt motor is working at full load and if shunt field circuit suddenly opens
Q.7
If a D.C. shunt motor is working at no load and if shunt field circuit suddenly opens
Q.8
Differentially compound D.C. motors can find applications requiring
Q.9
At the instant of starting when a D.C. motor is put on supply, it behaves like
Q.10
Which D.C. motor has got maximum self relieving property?
Q.11
The speed of a motor falls from 1100 r.p.m. at no-load to 1050 r.p.m. at rated load. The speed regulation of the motor is
Q.12
For a D.C. shunt motor if the excitation is changed
Q.13
A three point starter is considered suitable for
Q.14
The main disadvantage of the Ward-Leonard control method is
Q.15
For the same H.P. rating and full load speed, following motor has poor starting torque
Q.16
Which D.C. motor is generally preferred for cranes and hoists?
Q.17
One D.C. motor drives another D.C. motor. The second D.C. motor when excited and driven
Q.18
Which D.C. motor has got maximum self loading property?
Q.19
In D.C. machines the residual magnetism is of the order of
Q.20
In a D.C. generator, the iron losses mainly take place in
Q.21
Where D.C. motor of H.P. 12 or more requires frequent starting, stopping, reversing and speed control
Q.22
Ward-Leonard control is basically a
Q.23
For constant torque drive which speed control method is preferred?
Q.24
By looking at which part of the motor, it can be easily confirmed that a particular motor is D.C. motor?
Q.25
Which of the following motors is most suitable for signalling devices and many kinds of timers ?
Q.26
The mechanical power developed by a shunt motor will be maximum when the ratio of back e.m.f. to applied voltage is
Q.27
When two D.C. series motors are connected in parallel, the resultant speed is
Q.28
Which of the following losses are significantly reduced by laminating the core of a D.C. generator?
Q.29
In case the conditions for maximum power for a D.C. motor are established, the efficiency of the motor will be
Q.30
The direction of rotation of a D.C. series motor can be changed by
0 h : 0 m : 1 s