Multi-motor variable-frequency starting control emergency power supply controlled by PLC (Programmable Logic Controller)

Abstract

The utility model discloses a PLC-controlled multi-motor frequency conversion starting control emergency power supply, a three-phase power supply is divided into five paths of output, the first path of power supply output is connected with a circuit breaker 1QF and a contactor 1KM1 in sequence and then is connected with a motor M1; the second path of power supply output is connected with a circuit breaker 2QF and a contactor 2KM1 in sequence and then is connected with a motor M2; the third path of power supply output is connected with a circuit breaker 3QF and a contactor 3KM1 in sequence and then is connected with a motor M3; a fourth path of power supply output is sequentially connected with a circuit breaker QF and a frequency converter UF, then is respectively connected with contactors 1KM2, 2KM2 and 3KM2, and then is respectively connected with a motor M1, a motor M2 and a motor M3; the fifth path of power supply output is sequentially connected with a circuit breaker QFC and a contactor KM and then is respectively connected with high-frequency switching power supplies 1CHG and 2CHG to charge a storage battery pack GB through a circuit breaker QFD; under the condition of commercial power, one frequency converter can drag a plurality of motors to start in a variable frequency manner in a time-sharing manner, and when the commercial power fails, the frequency converter drags one of the motors to work, so that economic loss caused by the commercial power failure is avoided.

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