(A) Power Supply Fault Inspection: Fault Status: After powering on, the entire device does not respond, and the operation display panel shows no display. The measured 24V and 10V control power at the control terminals are both 0V. Fault Essence: The VFD’s switching power supply is not working. Troubleshooting Approach: (1) Switching voltage fault; (2) Pre-charging circuit fault. Troubleshooting Method:(1)…
Month: June 2024
The repair process of an unlicensed VFD caught up with lightning speed
In movies and TV shows, when a Taoist from Maoshan encounters an urgent and difficult situation, he often recites a curse: “The Supreme Old Lord is as sick as a law… If something difficult happens, it should be solved by the curse.”. If there is an urgent VFD repair, we can also recite a few mantras and find the “smart”…
Analog circuits used in VFD fault detection circuits
The main circuit of the fault detection circuit is still composed of an operational amplifier. Usually, the operational amplifier is connected to the following types of circuits, completing three tasks of signal analog amplification, comparative output, and precision rectification.(A)、 Inverting amplifier circuit: Operational amplifier reverse amplification circuit An operational amplifier has excellent characteristics such as high input impedance (without using…
How to conduct load testing on VFD drive circuits to solve the problem of normal no-load and load failure?
The voltage amplitude of the six driving pulses outputted by the driving circuit meets the requirements. For example, measuring the amplitude of the positive excitation pulse voltage in the AC range is about 14V, and the amplitude of the negative cutoff voltage is about 7.5V (different models may vary). After the above inspection of the driving circuit, most maintenance personnel…
Maintenance ideas and methods for VFD switching power supply
The switching power supply circuit of VFD can be completely simplified into the circuit model shown in the diagram, and the key elements in the circuit are included. And any complex switching power supply, after removing the branches, will still have a backbone like the one shown in the picture. In fact, in maintenance, it is necessary to have the…