Friday, 8 July 2016

A note about slip test

It is conducted to calculate unsaturated Xd and Xq.
We feed subnormal voltage to armature, mechanically rotate  it, keep field open ( Vf) 
Here Nr is not equal to Ns.
but is almost equal to Ns.
Since mmf due to armature reaction is rotating at Ns, field poles gradually slip w.r.t. rotating armature mmf.
Thus R = 1/ u of path of mmf changes at twice slip freq. from maxm when axis of poles and axis of armature reaction  wave coincide and minm. when they are at right angles.

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