FAQ of apcups power supply maintenance

Apcups power supply plays an important role in protecting data and machine equipment from damage. Therefore, it is very important to use and maintain UPS correctly. Many users are limited to the precautions in the product manual. Apcups power supply plays an important role in protecting data and machine equipment from damage. Therefore, it is very important to use and maintain UPS correctly. Many users are limited to the precautions in the product manual.

1. A pair of power amplifier transistors of inverter power stage are damaged. After replacement of transistors of the same type, the reason why the transistors burn out after a period of operation is that the current is too large, and the reasons for the excessive current are as follows:

——Overcurrent protection failure. When the inverter output overcurrent, the overcurrent protection circuit does not work;

——When pulse width modulation (PWM) module fails, the output two complementary waveforms are asymmetric, one of them has a long conduction time, while the other has a short conduction time, which makes the two arms work unbalanced, or even the two arms are connected at the same time, causing damage to the two tubes;

——The parameters of the power tube are quite different. At this time, even if the symmetrical wave is input, the output will also be asymmetric. This wave will cause magnetic bias through the output transformer, that is, the magnetic flux balance, which will lead to the saturation of the transformer and the sudden increase of the current. The power tube will be burnt out, and one will be burnt out, and the other will be burnt out.

2. The battery voltage is low, but it can not be charged for more than ten hours after starting.

Fault analysis: judging from the phenomenon as battery or charging circuit fault, check as follows:

——Check whether the input and output voltage of the charging circuit is normal;

——If the charging circuit input is normal and the output is abnormal, disconnect the battery

Retest, if it is still abnormal, it is charging circuit fault;

——If the input and output of the charging circuit are normal after the battery is disconnected, it means that the battery has been damaged due to long-term non charging, over discharging or reaching the service life.

3. The ups output is normal when the power supply is available, but the buzzer will beep for a long time when the power supply is not available.

Fault analysis: judging from the phenomenon as partial fault of battery and inverter, check according to the following procedures: (relevant content: UPS price)

——Check the battery voltage to see if the battery is under charged. If the battery is under charged, check whether it is the battery itself or the charging circuit.

——If the working voltage of the battery is normal, check whether the driving circuit of the inverter works normally. If the output of the driving circuit is normal, it means that the inverter is damaged.

——If the inverter drive circuit does not work normally, check whether the waveform generation circuit has PWM control signal output. If there is control signal output, it means that the fault is in the inverter drive circuit.

——If the waveform generating circuit has no PWM control signal output, check whether its output is blocked due to the operation of the protection circuit, if so, find out the protection reason;

——If the protection circuit does not work and the working voltage is normal, and the waveform generation circuit has no PWM waveform output, it means that the waveform generation circuit is damaged.

The above troubleshooting sequence can also be reversed, sometimes the fault can be found faster.

4. After UPS is turned on, there is no display on the panel and UPS does not work.

Fault analysis: judging from the fault phenomenon, the fault is in the mains input, battery, mains detection part and battery voltage detection circuit:

——Check whether the mains input fuse is burnt;

——If the mains input fuse is in good condition, check whether the battery fuse is burnt, because when some ups self checks the battery voltage, it will turn off all the ups output and display;

——If the battery insurance is in good condition, check whether the mains power detection circuit works normally. If the mains power detection circuit works abnormally and the UPS does not have no mains power start function, the UPS will also turn off all outputs and displays.

——If the city detection circuit works normally, then check whether the battery voltage detection circuit is normal.