Answer / venkatesh

the shunt connection in four point stater is provided
separately form the line where as in three point stater it
is connected with line which is the drawback in three point
stater

Answer / k.sathish kumar

In three point starter NVR (no voltage relay)is series with
shunt if voltage falls certain value NVR De energized due to
insufficient magnetic field and motor turned off. But in
four point starter NVR energized directly from DC supply
thus the draw back of 3 point starter rectified

Answer / v.l.kanth

a motor can be run for a higher speed than normal speed by reducing the field current. reduced the field current may not produce enough magnetic force to hold the handle in on position. so handle returns to off position. this is the disadvantage of three point starter.this is the advantage of four point starter. it will not returns to off position

Answer / saikat sshoo

In 4point starter a brass arc is present which is not present In 3point starter. A protective resistance is present In 4point starter which is not In 3point starter.

Answer / priyanka

As we know that dc machines are self starting ,we get high currents which leads to machine. So we use a three point starter to limit high currents and to control machine burn out's and sparkles.

Answer / anil kumar behera

In 4point starter a brass arc is present which is not present In 3point starter. A protective resistance is present In 4point starter which is not In 3point starter.

Answer / jasif farooq pala

Your Answerthe basic difference between in the circuit of 4 point stater as compared to 3 point stater is that, the holding coil is removed from shunt felid circuit and us directly connected across the line with a current limiting resistance R in series

Answer / sandeep

In case of any three pointstarter NVC is connected to the shunt field winding so if voltage is fall certain value the no volt release coil de magnetise so motor will be off. But in case of four point starter the no volt release coil is directly connected to the supply so the NVC no way the demagnetized.

Answer / deep

Explin the fundamental equations usedin design of electro magnet.

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