When installing a frequency converter, it is first necessary to understand the usage situation of the frequency converter and set different peripheral devices according to the on-site needs. The main peripheral devices of the frequency converter here include: air circuit breakers, electromagnetic contactors, AC reactors, braking resistors, DC reactors, output AC reactors, wireless noise filters, etc
1. An air circuit breaker is an automatic electrical appliance that not only contacts and disconnects circuits normally, but also operates under abnormal conditions such as overcurrent, reverse current, short circuit, and loss of (under) voltage. Its main function is to protect electrical equipment in AC and DC circuits, and can also operate the circuit infrequently. This is used to quickly cut off the frequency converter and prevent power failure caused by frequency converter and its circuit faults.
2. AC reactor, also known as AC reactor, is an AC reactor used for power coordination. Its main function is to prevent harmonic interference from the power grid.
3. AC contactor is abbreviated as contactor. It is an automatic electrical appliance used to frequently and remotely connect and disconnect AC/DC circuits, or large capacitance control circuits. This is mainly used to automatically cut off the main power supply and prevent power failure and restart after the frequency converter malfunctions.
4. Radio noise filter, also known as power filter, is mainly used to suppress the transmission of radio signals from metal pipe lines to equipment, or to suppress the transmission of interference signals from interference source equipment through power supply. The function in the frequency converter is to suppress interference signals from the frequency converter transmitted through the power line to the power supply or motor.
5. The DC reactor is mainly used to suppress the high-frequency harmonics generated by the frequency converter, and its effect is better than that of the AC reactor.
6. The output AC reactor, also known as the output side anti-interference filter, is designed to suppress the high-frequency interference generated by the frequency converter and filter the power side filter.
7. The filter cover is mainly used to prevent dust from entering the frequency converter.
The steps for installing the frequency converter are as follows:
1、 Goods inspection 2. Insulation test before installation of the main circuit 3. Insulation test before installation of the control circuit 4. Requirements for the surrounding environment during the installation of the frequency converter.
(1) Environmental temperature: Generally suitable for working at -10 ℃ -40 ℃, with a humidity change below 90%. If the ambient temperature is higher than 40 ℃, the frequency converter should be derated by 5% for every 1 ℃ increase.
(2) General requirements for the installation site: 1) No corrosion, flammable and explosive gases, liquids; 2) No dust, floating fibers, and metal particles. 3) The foundation and walls of the installation site should be sturdy, undamaged, and vibration free. 4) Avoid direct sunlight. 5) There should be no electromagnetic interference
(3) Installation space and ventilation of the frequency converter: The frequency converter is internally equipped with a cooling fan for forced air cooling. In order to achieve good cooling circulation, the frequency converter must be installed vertically. When installing multiple frequency converters in the same device or control box, it is recommended to install them horizontally and in parallel to reduce mutual thermal impact.
(4) Dismantling of the cover plate of the frequency converter: During installation, it is necessary to test, inspect, and wire the frequency converter, which requires dismantling the cover plate. Pay attention to the characteristics of different frequency converters and install them according to their characteristics.
(5) The wiring of the frequency converter: 1) Is there any error in the wiring? 2) Are the wire chips, especially metal chips, short ends, and their screws and nuts, falling inside the frequency converter? 3) Are the screws tightened and the wires loose? 4) Are the exposed parts of the terminal wiring touching the live parts of other terminals and touching the frequency converter shell.
(6) Precautions for control circuit wiring: 1) The wiring between the control circuit and the main circuit, as well as other power lines and power lines, should be separated and kept at a certain distance. 2) The relay contact terminal leads in the frequency converter control circuit should be separated from the wiring of other control circuit terminals to avoid interference signals when the contacts close or open. 3) In order to prevent interference caused by noise and other signals, which may cause misoperation of the frequency converter, the control circuit adopts shielded wires.
(7) Special installation for frequency conversion.
Precautions when using frequency converters:
1) Precautions for Physical Use Environment
The working temperature of the product is generally required to be between 0 and 50 ℃, but for work safety and use, allowance should be considered to control the load below 40 ℃. It is not allowed to install heating elements or heating elements close to the bottom of the frequency converter.
2) Electrical precautions
1. Preventing electromagnetic interference
2. Prevent input overvoltage
3) Precautions for parameter setting
Before using the frequency converter, set the output voltage of the frequency converter to 380V and the base frequency to 50HZ; Set the high frequency and upper limit frequency of the driving pump and fan loads to 50HZ, and the lower limit frequency to 15-20HZ; Acceleration and deceleration are determined based on the capacity and load capacity of the motor.
4) Precautions during wiring process
Terminal wiring is often required during installation, testing, and maintenance processes. Remember not to connect the power cord to the output terminal of the frequency converter; Do not mistake the "N" terminal on the output terminal block of the frequency converter for the neutral terminal of the power supply. The control circuit wiring should be as far away as possible from the main circuit wiring.
5) Grounding and lightning protection of frequency converters
The correct grounding of the frequency converter is an important means to improve the sensitivity of the control system and suppress noise. The smaller the grounding resistance of the frequency converter's grounding terminal E (G), the better. The cross-section of the grounding wire should not be less than 2 square millimeters. The length should be controlled at 20 meters. In areas with active lightning, if the power supply is an overhead incoming line, a frequency conversion dedicated lightning arrester should be installed at the incoming line, or a steel pipe should be embedded 20 meters away from the frequency converter to protect the grounding according to the specifications.
6) Precautions for frequency converter operation
During the trial operation, it is recommended to first run without load, then run with light load, and then run with load. The operation and stop of the frequency converter should not be done by turning on or off the power supply of the frequency converter.