Electrical machines miscellaneous Easy Questions and Answers

Electrical machines miscellaneous

6-pole lap-wound dc armature with 720 conductors draws 50 A from the mains. Its armature reaction per pole is

1. 1000 AT peak, triangular in wave shape.
1. 500 AT peak, sinusoidal in wave shape.
1. 1000 AT peak, sinusoidal in wave shape.
1. 500 AT peak, triangular in wave shape.

1. series excited and should have polarity opposite to that of the next main pole in the direction of rotation of armature.
1. series excited had should have the same polarity as that of the next main pole in the direction of rotation of the armature.
1. shunt excited and should have polarity opposite to that of the next main pole in the direction of rotation of the armature.
1. shunt excited and should have t he same polarity as the next main pole in the direction of rotation of the armature.

What would be observed if a dc shunt motor is started with an open-circuited field?

1. The motor does not pick up speed but draws only a small current
1. The motor does not pick up speed but draws a large current.
1. The motor picks up fast and acquires full speed while drawing large current
1. The motor picks up fast and acquires full speed while drawing small current.

A differentially compounded motor under highover-load conditions will behave like a/ an

1. shunt motor
1. series motor
1. cummulative compound motor
1. ac synchronous motor

ω_m	opposite to the direction of ω_m (speed in mech rad/s)
E_αI_α