Working principle of frequency conversion control cabinet
The core device of frequency conversion control cabinet is frequency converter, and the speed of motor mainly depends on the power frequency. In addition to the small slip rate, the speed of asynchronous motor is basically proportional to the power frequency, and the speed of synchronous motor is strictly proportional to the power frequency. Adjusting the output frequency of the inverter can change the speed of the motor.
The frequency conversion control cabinet is mainly used to adjust the working frequency of the equipment, reduce energy consumption, start the equipment smoothly, and reduce the damage to the motor caused by the large current generated when the equipment is directly started. At the same time, it has its own analog input (for speed control or feedback signal), PID control, pump switching control (for constant pressure), communication function, macro function (with different parameter settings in different occasions), multi-speed and so on. It can be widely used in industrial and agricultural production and automatic control of water supply, drainage, fire fighting, pressurization of spray pipe network, cold and hot water circulation of HVAC, etc.
Product characteristics of frequency conversion control cabinet
1, select internationally renowned brand frequency converters, programmable controllers and well-known brands of low-voltage appliances;
2, digital PID adjustment, keyboard operation, digital display, unattended automatic operation;
3. The circuit design is simple and clear, which is convenient for fault analysis and maintenance;
4, frequency conversion adjustment, effectively avoid the phenomenon of "water hammer".
5. The programming and setting of frequency converter and controller are convenient and simple, and easy to master.
6. Excellent performance, flexible control mode, strong anti-interference ability and stable and reliable work;
7, pipe network pressure is constant without impact, automatic/manual switching control;
8. The communication serial port can be connected with a computer to realize direct control of computer networking.
9. The water supply pressure is stable, and the system realizes closed-loop control, which can automatically adjust the difference between the system pressure and the set pressure to keep the system pressure constant.
10, in the automatic state, the water pump motor realizes soft start. It has no influence on power grid and pipe network, and greatly prolongs the service life of water pump, motor, pipeline system and electrical control system;
1 1, manual and automatic control functions can ensure the safe and continuous operation of the equipment;
12, the control is programmed, and various control modes can be realized according to the user's requirements. Such as: timing switch system, fire-fighting linkage, no-flow and zero-flow automatic shutdown sleep, centralized management of upper computer, etc.
13, multiple pumps operate alternately, so as to balance the average working time of each pump, prolong the service life of the pump, avoid the corrosion of the standby pump due to long-term non-operation, and ensure that the pump can be put into operation smoothly when a fire occurs;
14, with powerful basic control function and rich optional additional functions. Such as: timing switch system, automatic soft switch of water pump. Automatic shutdown, sleep, remote control and local control cabinet when using small flow and zero flow water.
15, perfect protection function, with short circuit, overcurrent, overvoltage, overheating, overload and other protection. If there is any fault in the operation of the pump, it will automatically stop working and give an alarm output; The system has the functions of self-inspection, fault judgment, fault memory, fault display, automatic start of standby pump and so on.
16. adopt PLC programmable controller, man-machine interface of pump unit and other equipment, supplemented by computer technology for intelligent control.
Control type of frequency conversion control cabinet
1. liquid level control: the control cabinet is equipped with a high-performance push-button float switch, which automatically controls the start and stop of the water supply and drainage pump according to the change of liquid level.
2. Pressure control: external electric contact pressure gauge or pressure controller can automatically start and stop the pump according to the pressure change of the pipe network. This type is widely used in household water supply and fire fighting pressurization system.
3. Temperature control: The external temperature controller is used to turn on or off the pump according to the set temperature range, which is suitable for constant temperature, heat exchange system and other occasions requiring temperature control.
4. Time control: The cabinet panel is equipped with a time setting button and a display, and the user can control the water pump on and off according to the timing requirements, which is suitable for the control of various timing or timing intermittent working modes.