低压三相电动机多功能保护装置的设计与应用

介绍了一种低压三相电动机多功能保护装置的研制过程。重点叙述了保护装置的总体结构和工作原理，给出了电流/电压输入电路、开关量输入电路、开关量输出电路、通信接口电路的设计方案。并分析了启动超时保护、堵转保护、电流不平衡保护和过热保护的工作原理，给出了保护装置的硬件配置图和典型应用电路图。该保护装置集保护、测量、控制、通信为一体，具有功能完善、高性价比、高可靠性的特点，可以对低压三相电动机所产生的各种故障进行全面的保护，提高电动机的使用率，延长电动机的使用寿命。

Design and application of multifunctional protection device for the low-voltage three-phase motor

The development of multifunctional protection device for the low-voltage three-phase motor is introduced. The overall structure and the operating principle are discussed and the schematic diagrams of current/voltage input circuit, switch signal input, switch signal output, and communication interface are given. This paper analyzes the operating principle of start-up out-time protection, locked rotor protection, unbalanced current protection and overheating protection, and also introduces the hardware configuration and the typical application circuit. The protection device combines with protection, measurement, control and communication, which has the features of perfect function, cost-effective and high reliability. It can provide full protection for the various faults of the low-voltage three-phase motor, and improve the utilization and extend the service life of the motor.