Novel PLC control motor power frequency and variable frequency circulation switching mode

The utility model relates to the technical field of motor automatic control, in particular to a novel PLC (Programmable Logic Controller) control motor power frequency and variable frequency circulation switching mode. The main motor and the auxiliary motor are both connected with a power frequency device and a frequency converter, the main motor and the auxiliary motor both adopt the design that the frequency converter controls the power frequency device to control a bypass, each group of control loops has an interlocking function, each control loop power supply is taken from an independent air switch, and the frequency converter control and the power frequency device control both have independent remote and local start-stop functions. Starting, stopping and switching of the frequency converter and the power frequency device are controlled by a PLC, the PLC has a fault closed circulation automatic switching function, the automatic switching function is started after the PLC comprehensively judges that operat