Answer / guest

when 3ph wdg is supplied with 3ph supply, a magnetic flux of
const magnetic field rotating at syn speed is produced at
stator.
at first half cycle(a period of 10 ms)N pole of rotor and N
pole of stator are repelled each other as well as S pole of
rotor and S pole of stator.in the next half cycle(a period
of 10 ms)poles of stator interchanged ie., N pole of rotor
and S pole of stator are attracted each other as well as S
pole of rotor and N pole of stator.
due to continuous and rapid rotation of stator poles, the
rotor is subjected to a torque which rapidly reversing.
because of its large inertia rotor cannot respond to such
reversing torque results remains stationary.hence
SYNCHRORONOUS MOTOR IS NOT SELF STARTING

Answer / baikunth

synchronous motor can run at synchronous speed or not. to
run the motor the rotor has to run at synchronous speed at
starting.

Answer / keerthirraj

synchronsous motor should be heavy load current capacity ,so synchronous motor not self start........to reduce the loss

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