Explain What will happen when direction of field current is
changed (i.e, field excitation is reversed) in the
following machines?
1) Alternator
2) Synchronous Motor
3) D.C Generator ( Shunt or Seies )
4) D.C Motor ( Shunt or Seies )
Answer Posted / tpfasil200
Direction of rotation of synchronous motor is determined b y its starting direction,as initiated by inducyion motor action. Thus, to reverse the direction of a 3 phase synchronous motor, it is necessary to first stop the motor and then reverse the phase sequence of the 3 phase connections at the stator. REVERSING THE CURRENT TO FIELD WINDINGS WILL NOT AFFECT THE DIRECTION OF ROTATION
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