Suntech UPS power supply, the input terminal has been regulated, and now there is no output after sudden shutdown, and it can still work normally after restart. What is the reason?

Excuse me, which series are you in Sander UPS, online or offline? If it is online, it is not recommended that you install voltage stabilizing equipment at the front or back end of UPS, because it is equivalent to connecting an LC line in series with UPS line, which will change the application environment of UPS.

Under normal circumstances, UPS will not stop suddenly unless the following situations occur:

1. Electromagnetic interference causes the DSP chip of the control panel to be abnormal, or the connector of the control panel is loose.

2. The abnormality of power grid leads to the abnormality of SPS (some lines of working power supply).

3.UPS internal explosion and bypass failure are rare.

If you want to repair it yourself, you can take apart the UPS to see the connection between the control panel and SPS, and then remove the voltage regulator in the power grid to see if the same phenomenon still exists. However, as long as the box is opened, there is no guarantee. I suggest you show it to Santer's engineers.