同步电动机异步全压启动过程的转矩分析

Torque Analysis of a Synchronous Motor during Asynchronous Start with Total Voltage

同步电动机在异步全压启动过程中,励磁绕组不能直接通入直流励磁电流,也不能开路。通常是把转子励磁绕组用附加电阻短接的方法,避免定子侧叠加电流烧坏电动机和绕组开路形成的高电压损坏励磁绕组。详细分析了同步电动机异步全压启动过程中接附加电阻产生的单轴转矩随转速变化的特性,提出在半同步转速时断开附加电阻的方法,改善同步电动机重载时的启动性能,提高电动机的安全可靠性。

During asynchronous start with total voltage of a synchronous motor, the excitation winding could neither input DC excita- tion current directly, nor to be open circuit. Generally, the rotor excitation winding is made short circuit with additional resistances to prevent stacked current induced by the stator side and high voltage generated by winding open circuit from damaging the motor. Ac- cording to detailed analysis of the characteristics that single axis torque varies with rotating speed during asynchronous start of a syn- chronous motor, this paper proposes the method that additional resistances is cut off to make excitation winding open circuit in semi- synchronous speed, so as to improve the starting performance, safety and reliability of synchronous motor when it is heaw loaded.