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Four Point Starter

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Four Point Starter

  • Figure B shows a four point starter with internal wiring diagram of a long shunt compound motor.
  • It will be noticed that No volt coil has been taken out of the shunt field winding and has been connected directly across the supply line through a protecting resistance ( R ).

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When the starting arm touches first stud, the line current divides into three parts.

  • One parts through starting resistance, series field and armature winding.
  • Second part passes through field rheostat and field winding.
  • Third part passes through no volt coil and protecting resistance.

It should be noted that any change of current in shunt field coil does not affect the function of the holding coil or no volt coil.

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  • One end of the field winding is connected to brass arc through holding coil.
  • One end of the armature winding is connected to starting resistance's last stud. A spring is placed over the lever of the starter arm.

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