A dc separately excited motor has constant field current. The armature is fed fr

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Question
A dc separately excited motor has constant field current. The armature is fed from a single phase supply through a full converter. When a = 0, speed is 500 rpm. If a = 45�, the speed is likely to be
Options
A. about 350 rpm
B. about 250 rpm
C. about 175 rpm
D. about 125 rpm

Correct Answer

about 125 rpm

Explanation

Average output voltage ? cos a and therefore reduced to 0.707 of the value for a = 0. Speed is nearly proportional to voltage.

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3. Most of the memory chips in static RAM
Options
A. do not require any supply
B. need 2 V supply
C. need 5 V supply
D. need 12 V supply

7. In a single phase full wave regulator, the firing angles in the positive and negative half cycles are generally
Options
A. equal
B. different
C. equal or different
D. different but sometimes equal

8. The real part of complex dielectric constant and tan? for a dielectric are 2.1 and 5 x 10^-4 at 100 Hz respectively. The imaginary part of dielectric constant at 100 Hz is
Options
A. 1.05 x 10^-3
B. 2.1 x 10^-3
C. 5 x 10^-3
D. 1.05 x 10^-2

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