8 Forbidden Areas for Control Circuit Wiring of Frequency Converter for Electrician
The daily work of the electrical industry and industrial control personnel is almost inseparable from the frequency converter. Experienced veterans know that the frequency converter not only supports the panel operation mode, but also provides an external terminal (auxiliary terminal) control mode suitable for remote and centralized control. Press in the wire of the auxiliary control terminal of the frequency converter to realize the above control circuit. Its functions are diverse and comprehensive, which is the only choice for frequency converter control today.Although the auxiliary control method of frequency converter has many advantages, the improper control circuit wiring can often affect the operation of frequency converter and sometimes cause unnecessary faults. Today, based on the work experience of some people, Xiaobian summarized the eight forbidden areas of inverter control circuit wiring. Let's have a look.1. The conductor of frequency converter control circuit shall be strictly distinguished from the main circuit cable (power line) and placed separately. This can effectively prevent the control circuit of the frequency converter from being disturbed by harmonics in the main circuit of the frequency converter.2. The wiring of the frequency converter shall be separated from the terminals or contacts of other control circuits in order to avoid high-voltage breakdown fault. Because of the fault signal of the frequency converter and the output signal of the multi-functional contact, it is very likely to drive the high-voltage AC contactor / relay.3. In order to avoid wrong operation caused by interference signal, shielded wire and twisted pair with high-quality anti-interference ability shall be selected when wiring the low-power control circuit of the frequency converter (such as the wire used by the sensor under PID control function). And it shall be wired separately from the main circuit and strong current circuit (including 200V relay program circuit).4. Take the wire length of the frequency converter control circuit 50m as the reference point (in some cases, the length is 100m, which is related to the decisive factors such as the wire section, material and signal strength). Once the wiring distance is higher than this length, the relay circuit or relay shall be used to amplify the signal.5. When crimping the control circuit wire of the frequency converter, pay attention to the polarity of the analog signal to avoid the destruction of the auxiliary control electronic circuit of the frequency converter due to the opposite polarity.6. When the frequency converter is powered on, disable the digital multimeter with buzzer function gear (the output voltage of this gear is higher than other gears) to measure the on / off of the control circuit. The reason for this is to prevent the power in the digital multimeter from being transmitted to the frequency converter control terminal through the probe, resulting in misoperation and failure!7. Because the frequency input signal of the control circuit is a small current, in order to avoid the fault caused by poor contact, two parallel nodes or twin nodes shall be used for the small signal contact.8. Cables of 0.3 0.75 square meters are generally selected for the wiring of control circuit.