Monday, November 11, 2013

A 4 point starter is used to start and control the speed of a (GATE-EE-2011)

A 4 point starter is used to start and control the speed of a (GATE-EE-2011)

(A) dc shunt motor with armature resistance control
(B) dc shunt motor with field weakening control
(C) dc series motor
(D) dc compound motor


Answer: option (A)

The armature current of DC shunt motor

Ia = (V- Eb) /Ra.

at the time of starting, Eb = 0. If the full supply voltage is applied to the motor, it will draw a large current due to low armature resistance.
A variable resistance should be connected in series with the armature resistance to limit the starting current.

7 comments:

  1. why 4 pointer is not used to control the shunt motor with field weakening control

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  2. 3 point starter has the drawback of field weakning to achieve the speed above the rated speed

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  3. I think 4 point starter used for field weking cantrol

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  4. Four point starter used for above rated Speed. So, answer is B

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  5. Because in 4 point starter No Volt Coil directly connected to the supply voltage

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  6. DC shunt motor with armature resistance control

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