偏差继电器
biased relay
频率继电器
frequency relay
频率灵敏继电器
frequency sensitive relay
欠流继电器
undercurrent relay
欠载继电器
underload relay
全继电器自动控制系统
all-relay automatic system
欠压
undervoltage
欠压保护
undervoltage protection
欠压释放器
undervoltage release
欠
lack of; not enough; owe
欠饱和流体
undersaturated fluid
欠补偿
under compensated
欠场同步电动机
permanent-field synchronous motor
欠处理
undercuring
欠处治
undercuring
欠单
accommodation kite; accommodation note; accommodation paper
欠电子
deficit electrons
欠叠
underlap
欠对准
misalignment
欠发达国家
less developed countries