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There is no display when the inverter is powered on. How to repair?

Oct 21, 2020

There is no display when the inverter is powered on. How to repair?

With the continuous advancement of science and technology, the requirements for maintenance electricians are getting higher and higher. In order to adapt to the continuous development of society, as an electrician, you need to continue to learn, otherwise it is really difficult to keep up with the pace of social development.

Nowadays, inverters are used in more and more occasions and become more and more popular. However, some maintenance electricians are inexplicably afraid of some faults of the inverter for various reasons. Even simple faults are feared and unknown. From where to start, today, let’s talk about a very common fault of the inverter. The inverter has no display when it is powered on. After removing the power supply problem, you can simply follow the steps below to find the internal cause.

The input external power supply mentioned here is 380 volts. According to the power supply sequence, first check whether the fuse is burned out. This is the only way that has not changed for thousands of years, and it is the most conventional. Don’t put the cart before the horse in a hurry.

Secondly, look at the circuit board as a whole for any obvious burnt-out components, such as resistance cracks, breaks, and desoldering; or capacitor bulges and dust on the circuit board. When you look at it, you must be careful and don’t go too far. Some failures may be due to one The fault point is ignored. It is best to check it carefully with a flashlight, and use a multimeter to measure the doubtful part.

When no problems are found in the above two points, we must start our detailed inspection. The first test is whether the output large capacitor is lost or damaged. This requires repeated and meticulous measurements. It is best to use a digital bridge meter. If there is no problem, then check the DC bus voltage of 570 volts. The voltage measured here is generally a little higher, but generally not low; if it is normal, then check whether the DC 12 volts and 5 volts are output, here What is said is the DC part, which can be easily determined with a DC meter.

If there is no problem, follow the steps again to check whether the pulse width regulator has output, whether the high-frequency transformer is vibrating, and whether the FET is broken down. It is recommended to use a pointer meter to measure this step. The result will look clear at a glance. Sometimes the number of the digital meter jumps sharply, which affects the judgment.

The above is mainly about the inspection of the switching power supply part of the frequency converter, and this non-display fault is mostly related to the power supply.

Finally, please remember that before repairing the fault, remember that the inverter must be discharged, especially the high-power inverter. This operation is essential, after all, safety first.