In the electrical industry and industrial control personnel, frequency converters are almost indispensable in their daily work. Experienced operators know that frequency converters not only support panel operation but also provide external terminal (auxiliary terminal) control methods suitable for remote, centralized control. By pressing wires into the auxiliary control terminals of the frequency converter, the above control loops can be realized. With its diverse and comprehensive functions, it is the top choice for frequency converter control today.
While inverter auxiliary control methods offer many advantages, improper control loop wiring can frequently impact inverter operation and sometimes even cause unnecessary malfunctions. Today, based on the experience of some professionals, we've summarized eight major pitfalls in inverter control loop wiring. Let's take a look.
1. The wires of the inverter control circuit must be strictly separated from the main circuit cables (power lines) and placed separately. This can effectively prevent the inverter control circuit from being interfered with by harmonics in the inverter main circuit.
2. The inverter's wiring should be separated from the terminals or contacts of other control circuits to avoid high-voltage breakdown faults. This is because the inverter's fault signals and multi-function contact output signals are highly likely to drive high-voltage AC contactors/relays.
3. To avoid erroneous operation caused by interference signals, when wiring the low-power control circuit of the frequency converter (such as the wires used for sensors under PID control function), high-quality shielded wires and twisted-pair cables with strong anti-interference capabilities should be selected. Furthermore, they should be wired separately from the main circuit and high-voltage circuits (including 200V relay program circuits).
4. Using the length of the inverter control circuit wires at 50m as a reference point (in some cases the length is 100m, depending on the wire cross-section, material, signal strength and other decisive factors), once the wiring distance exceeds this length, a relay circuit or relay should be used to amplify the signal.
5. When crimping the control circuit wires of the frequency converter, pay attention to the polarity of the analog signal to avoid damage to the auxiliary control electronic circuit of the frequency converter due to reverse polarity.
6. When the inverter is powered on, do not use a digital multimeter with a buzzer function (the output voltage of this mode is higher than other modes) to measure the continuity of the control circuit. This is to prevent the electrical quantity in the digital multimeter from being transmitted to the inverter control terminals through the probes, which could lead to malfunctions and failures!
7. Because the frequency input signal of the control circuit is a tiny current, in order to avoid failures caused by poor contact, two parallel nodes or twin nodes should be used for the tiny signal contact when inputting at the node.
8. For the wiring of control circuits, cables with a diameter of 0.3 to 0.75 square meters are generally selected.
Disclaimer: This article is a reprint. If it involves copyright issues, please contact us promptly for deletion (QQ: 2737591964). We apologize for any inconvenience.
