Evaluation and maintenance of UPS power hybrid power failure: overload, normal operation, fault elimination
Online UPS power supply, the bypass is normal, press the On switch, there is no response, the relay is not closed, and the inverter cannot operate.
Fault analysis and repair:
According to the fault phenomenon, it can be roughly in the panel circuit or the relay circuit Judge the fault. Open the shell, remove the panel, and measure the relay with a multimeter. This is normal. Since the on switch does not work, it is suspected that the on switch is damaged. Use a multimeter to connect a red pen and a black pen to both ends of the switch.
Press the on switch, the resistance is 0Ω, indicating that the on switch is good. Turn on the power, use the DC voltage scale of the multimeter to measure the DC voltage between the two ends of the switch and the ground. It is found that there is voltage at one end and no voltage at the other end. The non-voltage end is connected to the resistance R100 through the resistance R99, and then the voltage between the two ends of R99 is measured with a multimeter.
There is voltage at one end, but there is no voltage at the end connected to on. Close the power supply, measure the resistance value of R99 infinitely online, and measure the power resistance value of R99 at the same time. The resistance value should be 100kΩ. Replace the 100kΩ resistor, press the power supply, press the on switch, the inverter can work, the output voltage is 220vac, the load is connected, the ups power supply is normal, and the fault is eliminated.
