A PLC, or Programmable Logic Controller, is a general-purpose automatic control device with logic, sequential, timing, counting, and arithmetic control functions. It is widely used in machinery manufacturing, metallurgy, electronics, and other fields due to its small size, low power consumption, high speed, high reliability, and significant flexibility and expandability. Fans are common equipment in industrial production; traditional electrical controls suffer from poor reliability and flexibility. Switching to PLC control improves system stability and safety.
Its working principle is as follows: The PLC controls the high-pressure blower, a common piece of equipment in the normal production process. When the blower needs to be started during industrial production, the PLC first sends a signal to confirm that the blower valve blades are in the closed position to reduce the starting load. Then, according to the designed program, the PLC first starts the blower motor with the coil connected in a star configuration. After reaching a certain speed, the PLC then switches the motor coil to a delta configuration for operation, achieving energy saving and ensuring safety and reliability.
Technical methods:
1. When starting the fan motor, first close the fan valve. After the fan is running normally, open the fan valve according to production needs to reduce the starting load of the fan.
2. When the motor starts, the coil is connected in a star configuration. After the motor reaches its normal speed, it switches to delta configuration. This way, the starting current is 1/3 of that of DC starting.
3. When the motor coil switches from star to delta configuration, the PLC operates at high speed and has a short internal switching time, while the contactor takes a long time to switch. Therefore, the PLC's internal program design includes an internal lock to prevent sparking.
4. The system is designed with an emergency stop button to prevent accidents from occurring during startup and interconnection.
5. When the motor switches from star start to delta operation, the relevant contactors are interlocked to prevent the PLC from malfunctioning.
6. When designing a specific system, time settings can be configured using appropriate data based on the performance of the relevant electrical equipment.
