Switching general-purpose inverter frequency conversion and power frequency line with relay - News - Global IC Trade Starts Here.

Photocoupler

2. Working principle

The SA is a running mode selection switch. When SA dials to "power frequency operation", press the start button SF1, the intermediate Relay KA1 sucks and self-locks, KM3 acts, the motor M enters "power frequency operation", press ST1, the motor M stops.

When SA dials to “frequency conversion operation”, press start button SF1, KA1 moves and locks itself, KM2 moves, connects motor M to the output end of UF, then KM1 also acts, then press SF2. Intermediate relay KA2 action The inverter's FWD and CM are connected, the motor starts to rise, and enters the "frequency conversion operation" state. After the KA2 is actuated, the stop button ST1 is disabled to prevent the M from being stopped by directly cutting off the power of the UF.

During the running of the inverter, if UF trips due to fault, “30B~30A” will be disconnected, contactors KM2 and KM1 will be powered off, and the inverter and power supply, and between M and UF will be cut off; At the same time, "30B~30C" is closed, and the buzzer HA and the indicator HL perform an audible and visual alarm. At the same time, the KT coil of the time delay relay is energized. After the delay is over, the contact is turned on, so that KM3 acts, and M automatically enters the power frequency operation state. At this point, the operator should turn the SA to the "power frequency operation" position in time, and the sound and light alarm stops.

When the inverter is running, if the stop button ST2 is pressed, the intermediate relay KA2 is de-energized, and the FWD of the inverter is disconnected from the CM, and M will automatically decelerate to terminate the shutdown.

3. Application

This line can realize the switching function of frequency conversion and power frequency.