Three-phase voltage regulator principle Three-phase voltage regulator wiring method

Three-phase voltage regulators are widely used in the industrial field. They can achieve precise temperature control by adjusting the voltage, current and power applied to the load. And with its advanced digital control algorithm, it optimizes the efficiency of electric energy use and plays an important role in saving electric energy. Next, let's learn about the principle and wiring of three-phase voltage regulators.

1. Principle of three-phase voltage regulator

A three-phase voltage regulator is an adjustable autotransformer that can be used as a stepless and smooth voltage regulation device to drive a three-phase load. It is also called a thyristor power regulator, a thyristor power regulator, or simply a power regulator.

The working principle of the three-phase voltage regulator is to connect a four-layer three-terminal semiconductor device between the power supply and the load, and with the corresponding trigger control circuit board, the voltage, current and power added to the load can be adjusted. It is mainly used for the heating power adjustment of various electric heating devices. It can be adjusted "manually" or in conjunction with electric regulating instruments, intelligent regulating instruments, PLC and computer control systems to achieve constant value or program control of the heating temperature.

2. Three-phase voltage regulator wiring method

The A, B, and C terminals of the three-phase voltage regulator are the input terminals, the a, b, and c terminals are the output terminals, and the 0 terminal is the star (Y-shaped) neutral point.

Generally speaking, the input line is relatively fixed, so all three-phase four-wires are connected. The output depends on the load. If the three phases are balanced (such as motors, etc.) or a triangle connection is required, the 0 line can be left unconnected, otherwise the 0 line must be connected.

The grounding wire must be connected according to the regulations, and there is no need to separate the grounding.

3. Precautions for operation of three-phase voltage regulator

1. When conducting high-voltage tests, two or more persons must participate, and the division of labor and the method of communication between them must be clearly defined. There must also be a dedicated person to monitor site safety and observe the test status of the test product.

2. The three-phase voltage regulator and control box should have reliable grounding.

3. During the test, the voltage boost speed cannot be too fast, and sudden full voltage power-on or power-off is never allowed.

4. During the voltage step-up or withstand voltage test, if the following abnormal conditions are found, the voltage should be immediately reduced, the power supply should be cut off, the test should be stopped, and the cause should be found before the test is repeated. ① The pointer of the voltmeter swings greatly. ② There is a smell of burning insulation or smoke. ③ There is an abnormal sound inside the tested product.

5. During the test, if the test product is short-circuited or breaks down due to a fault, the overcurrent relay in the control box of the oil-immersed high-voltage test transformer will operate. At this time, return the voltage regulator to zero and cut off the power supply before taking out the test product.

6. When conducting a capacitance test or a DC high-voltage leakage test, after the test is completed, lower the voltage regulator to zero and cut off the power supply. Then, use a discharge rod to discharge the high-voltage end of the test sample or capacitor to the ground to avoid the risk of electric shock from the potential remaining in the capacitor.