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

The_______is a crystal which, under pressure, produces an electric current which varies with the pressure A.alternator B.glass thermometer C.bourdon tube D.piezoelectric pressure transducer

下列选项中表示火花塞的是哪一项？ A: ignition B: electric spark C: spark plug D: alternator

The frequency of an alternator at a given r/min is determined by the _______ . A.number of turns of wire in the armature coil B.number of magnetic poles C.strength of the magnets used D.output voltage

【单选题】What is a key characteristic of a permanent magnet alternator? A. Permanent magnet stator B. Permanent magnet rotor C. Permanent magnet rotor and stator D. The use of a strong NIB magnet

The magnetic field of the dynamo or alternator can be provided by either electromagnets or permanent magnets mounted on either the rotor or the stator. A: 通过安装在转子或定子上的电磁铁或永磁铁，可以形成直流发电机或交流发电机所需的磁场。 B: 通过被安装在转子或定子上的电磁铁或永磁铁，可以形成直流发电机或交流发电机所需的磁场。 C: 通过被安装在转子或定子上的电磁铁或永磁铁，我们可以形成直流发电机或交流发电机所需的磁场。 D: 通过被安装在转子或定子上的电磁铁或永磁铁，可以提供直流发电机或交流发电机所需的磁场。