Winding type asynchronous motor p=3, if the stator current f1=50Hz, rotor speed n=900r/min, the rotor potential frequency f2= _____. Asynchronous motor knowledge f2=sf1, the number of pole pairsp=3,stator speed n0=1000r/min,slip rates=(n0-n)/n0. Choose A,B or C. 异步电动机知识