High-voltage inverter interference case problem analysis and processing - Database & Sql Blog Articles

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1. How to judge the interference problem of the high-voltage inverter The interference problem of the high-voltage inverter is mainly reflected in the operation of the motor. For example, the motor suddenly stops during the running process, the motor runs fast and slow, the running speed is unstable, the motor can't stop, the button can't play any role, etc. These are the manifestations of the interference of the high-voltage inverter.

2. The third way to deal with the grounding interference problem is to ensure good grounding. The general requirements for the grounding terminal are: grounding terminal is grounded in "third way" (separate grounding), the shorter the grounding wire, the better, and It must be well grounded; the control circuit line uses shielded wire, and the shielding wire at the far end of the shielded wire is suspended and the grounding is at the near end; according to the product requirements, reasonable wiring, strong and weak electricity separation, maintain a certain distance, avoid high-voltage inverter power line and signal line Parallel wiring, should be distributed wiring; increase anti-radio interference filter, high-voltage inverter input and output anti-interference filter or reactor; take shielding measures to prevent electromagnetic induction, and even shield high-voltage inverter with metal iron box; Carrier frequency; if communication function is used, rs485 communication line uses twisted pair. Below, I will do a specific analysis for different interference situations in actual use.
3. Three-phase five-wire power supply has encountered such a situation, the high-voltage inverter has been running, pressing the stop button does not work, after inspection, the ground wire of the high-voltage inverter is only connected with the neutral line of the transformer. The neutral line of the transformer is not connected to the earth. After the neutral line of the transformer is grounded, the high-voltage inverter returns to normal. Many small factories nowadays generally do not pay attention to the connection of the ground wire. When the machine is shipped, according to the standards stipulated by the National Electrical Code, The ground and neutral lines are strictly separated. The neutral line in the power distribution cabinet has dedicated terminal blocks, and the ground wire has special grounding screws. Since the user came from the transformer three phase lines and one neutral line, only the neutral line was connected to the "n" terminal, and the ground line was not connected to the neutral line. Although the control line used shielded lines, the shielding layer was also The grounding screw was received, but it was not connected to the earth, and it could not be shielded. As a result, the high-voltage inverter could not stop because of the uncontrolled motor. After connecting the neutral line and the ground line in the power distribution cabinet, it will return to normal. You can also connect the ground wire in the power distribution cabinet directly to the earth. Many users adopt the method of connecting the ground line to the neutral line. However, the disadvantage of using this method is that if the neutral line is disconnected, starting a certain action of the machine tool may cause the machine to be charged, posing a safety hazard to the person. This type of interference is a type of interference in the high-voltage inverter itself. (http:// Copyright)

4. Case of interference from external equipment to high-voltage inverter (1) phenomenon. The motor can't stop occasionally. After checking that the shield is properly grounded, reducing the carrier frequency does not work. The magnetic loop filter on the input side and output side of the high voltage inverter does not work.
(2) Analysis. The power distribution cabinet with high-voltage inverter is too close to the power distribution room. The power distribution cabinet of the power distribution room has a large current flowing through it. There is a strong magnetic field around the current, which interferes with the normal operation of the high-voltage inverter and keeps the power distribution cabinet away. After the power distribution room returns to normal, this is an interference from external equipment to the high-voltage inverter.
5. Case of interference of high-voltage inverter to external equipment (1) phenomenon. After starting the high voltage inverter, the motor does not operate.
(2) Analysis. The high-voltage inverter is given the operating frequency by the external 4-20ma, and the 4-20ma DC signal is sent by the transmitter. Looking at the display panel, the frequency is displayed as 0.00. The output of the transmitter was measured with an ammeter and found to have no output. After the output terminal of the transmitter is connected with a capacitor of 102, it is restarted and the device returns to normal, indicating that the signal source is disturbed. A simple signal line shunt capacitor solves the big problem in engineering practice and is a practical method that is often effective. This is a disturbance of the high-voltage inverter to external equipment.