frequency relay [电] 频率继电器 ; 频率电驿

under frequency relay 低频率继电器

frequency measuring relay 测频继电器

relay operating frequency 继电器工作频率

low-frequency relay 低频继电器

voice-frequency relay [通信] 音频继电器

high-frequency relay [电] 高频继电器

slip frequency relay 差频继电器

low frequency relay 低周率继电器

frequency sensitive relay [电] 频敏继电器