Sync check relay a sync check relay is an electrical device that monitors the phase relationship between two voltage sources and provides a signal when the voltage sources are within specific preset parameters 同步检查继电器同步检查继电器是监测两个电压源之间的相位关系的电气设备，如果电压源间的关系在预定的参数范围内，它就会发出相应信号。
