1. The UPS output is normal when there is mains, and the buzzer sounds when there is no mains, no output. Fault analysis: Judging from the phenomenon that the battery and the inverter are partially faulty, the following procedures can be checked: 1) Check the battery voltage to see if the battery is not fully charged. If the battery is not fully charged, check whether the battery itself is faulty or the charging circuit is faulty. 2) If the working voltage of the battery is normal, check whether the inverter drive circuit works normally. If the output of the drive circuit is normal, the inverter is damaged. 3) If the inverter drive circuit is not working properly, check whether the waveform generation circuit outputs PWM control signal. If there is control signal output, the fault is in the inverter drive circuit. 4) If the waveform generation circuit has no PWM control signal output, check whether the output is blocked due to the protection circuit operation, and if so, find the protection reason; 5) If the protection circuit is not working and the working voltage is normal, and the waveform generation circuit has no PWM waveform output, the waveform generation circuit is damaged. The above troubleshooting sequence can also be reversed, sometimes finding faults faster. 2. The battery voltage is low, but the battery voltage is still not charged when the battery is turned on for more than ten hours. Fault analysis: If the battery or charging circuit is faulty from the phenomenon, you can check the following steps: 1) Check if the input and output voltage of the charging circuit is normal; 2) If the input of the charging circuit is normal, the output is abnormal, and the battery is disconnected; 3) Retest, if it is still not normal, the charging circuit is faulty; 4) If the input and output of the charging circuit are normal after disconnecting the battery, it means that the battery has been damaged due to long-term uncharged, over-discharged or has reached the end of life. 3. The inverter power stage is damaged by a pair of power amplifier transistors. After replacing the same type of transistor, the reason why the running is burned for a while is that the current is too large, and the cause of excessive current is: 1) Overcurrent protection is invalid. When an overcurrent occurs in the inverter output, the overcurrent protection circuit does not function; 2) Pulse width modulation (PWM) component failure, the output of the two complementary waveforms is asymmetrical, one conduction time is long, and the other conduction time is short, so that the two arms work unbalanced, even the two arms are simultaneously turned on, resulting in two Tube damage; 3) The power tube parameters have a large difference. At this time, even if a symmetric waveform is input, the output will be asymmetrical. The waveform will be biased by the output transformer, that is, the magnetic flux is unbalanced. The accumulation will cause the transformer to saturate and the current will suddenly increase and burn out. The power tube, while one burned out and the other burned out. 4. After the UPS is turned on, there is no display on the panel, and the UPS does not work. Fault analysis: Judging from the fault phenomenon, its fault is in the mains input, battery and mains detection part and battery voltage detection loop: 1) Check if the mains input fuse is burnt; 2) If the mains input fuse is intact, check whether the battery insurance is burnt, because some UPS will turn off all output and display of the UPS when the self-test does not have the battery voltage; 3) If the battery is in good condition, check whether the mains detection circuit works normally. If the mains detection circuit is not working properly and the UPS does not have the mains start function, the UPS will also turn off all output and display. 4) If the mains detection circuit is working properly, check if the battery voltage detection circuit is normal. 5. In the case of access to the mains, each time the UPS is turned on, the relay repeatedly hears the action. The UPS panel battery voltage is too low and the buzzer sounds long. According to the above fault phenomenon, it can be judged that the fault is caused by the battery voltage being too low, which causes the UPS to start unsuccessfully. Remove the battery and perform equalization charging (all batteries are charged in parallel). If it is still unsuccessful, only replace the battery. 6. When a backup UPS has utility power, it works normally. When there is no mains, the inverter has output, but the output voltage is low, and the transformer emits loud noise. Fault analysis: The output of the inverter indicates that the final drive circuit is basically normal. The noise of the transformer indicates that the two arms of the push-pull circuit are asymmetrical. The detection steps are as follows: 1) Check if the power is normal; 2) If the power is normal, check whether the output signal of the pulse width output circuit is normal; 3) If the output of the pulse width output circuit is normal, check if the output of the drive circuit is normal. 7. When the mains supply is normal, the UPS is turned on, the working indicator of the inverter flashes, and the buzzer sounds intermittent. The UPS can only work in the inverter state and cannot be switched to the mains working state. Fault analysis: The inverter power supply cannot be converted to the mains power supply, indicating that the inverter power supply has failed to the mains power supply conversion part. 1) Whether the mains input fuse is damaged; 2) If the mains input fuse is intact, check whether the output of the mains rectifier filter circuit is normal; 3) If the output of the commercial rectification and filtering circuit is normal, check whether the mains detection circuit is normal; 4) If the mains detection circuit is normal, check whether the output of the inverter power supply to the mains supply conversion control is normal. 8. Backup UPS When the load is close to full load, the mains supply is normal, and the battery fuse is blown when the battery is powered. Fault analysis: The battery fuse is blown, indicating that the battery supply current is too large. The detection steps are as follows: 1) Whether the inverter is broken down; 2) Whether the battery voltage is too low; 3) If the battery voltage is too low, check if the battery charging circuit is normal; 4) If the battery charging circuit is normal, check whether the battery voltage detection circuit works normally. 9, UPS can only be powered by the mains and can not be converted to inverter power. Fault analysis: The power supply to the inverter cannot be converted, indicating that the mains fails to the inverter power supply conversion. 1) Whether the battery voltage is too low, and whether the battery fuse is intact; 2) If the battery is partially normal, check if the battery voltage detection circuit is normal; 3) If the battery voltage detection circuit is normal, check whether the output of the commercial power supply to the inverter power supply is normal. 15V Power Adapter,15V4A Ac Dc Adapter,15Volt 4Amp 60W Power Adapter,15V4A Power Adapter ShenZhen Yinghuiyuan Electronics Co.,Ltd , https://www.yhypoweradapter.com