Windings字体的大写字母M是什么形状？

A single phase ac induction motor has two windings, one is a run winding and the other is called a start winding. Strat winding can only work for a very short time to avoid overheated. A _____________ switch is installed inside motor to disconnect the strat winding when the motor speed reached 75% RPM.

What is the use<br/>of electric heaters in the alternator?<br/>交流发电机内的电加热器的用途是什么?( ) A: They are used to<br/>warm up the alternator when starting.<br/>用于启动时给交流发电机加热。 B: They are used to<br/>prevent condensation on the windings when the alternator is not in<br/>use.<br/>用于防止当交流发电机不用时绕组上的冷凝。 C: They are used to<br/>keep the alternator warm when running.<br/>用于运转时保持交流发电机是热的。 D: They are used to heat up the cooling water.用于加热冷却水