4. The inverter working indicator light is normal, but the power supply is not outputting
Possible reasons may be that the operating point of the pulse width modulation device is misaligned or damaged; Short circuit or interlayer breakdown of the main power transformer (extremely unlikely); The two arms of the final push-pull driving transistor circuit are severely unbalanced; Damage to the conversion control circuit, etc.
5. When UPS is powered by an inverter, the backup working time cannot reach the rated full load power supply time for the following reasons:
(1) Excessive discharge of the battery causes the terminal voltage to approach the specified final voltage. In general, when the terminal voltage of each 12V battery is lower than 10.5V, it may cause startup failure:
(2) After discharging, if the battery does not have enough time to charge or the mains voltage runs at low voltage for a long time, the charging circuit fails to effectively charge the battery pack in a timely manner, and in severe cases, it cannot be charged at all:
(3) The battery is in a “float charging state” for a long time, which leads to an increase in internal resistance of the battery, resulting in the actual usable capacity of the battery being much lower than the rated capacity of the battery pack;
(4) The battery charging circuit is damaged or the charging voltage is not adjusted properly. Under normal mains power supply, the power supply can automatically use the charging circuit to “float charge” the battery, restoring the original performance of the battery pack. If the terminal voltage of the battery pack is too low, it is generally necessary to take the battery offline for balanced charging in order to restore the performance of the battery pack.
6. The main reasons for the “inverter working indicator light” stopping flashing and the buzzer sounding long are as follows:
(1) Frequent switching of UPS uninterruptible power supply resulted in startup failure. UPS does not operate in the mains power supply state, nor does it operate in the inverter power supply state. It is generally required to wait for at least 5-6 seconds after turning off the UPS power switch before restarting;
(2) UPS power supply automatically protects the circuit due to heavy load or low battery voltage;
(3) In some UPS systems, the timer components that control the working status indicator light and buzzer may be damaged;
(4) There are large loads or inductive loads connected in the UPS power load circuit or in the mains power supply network.
7. The transformer makes abnormal sound
The main reasons for its failure are as follows:
(1) The rectifier circuit and voltage stabilizer circuit are faulty, and the rectifier bridge or integrated voltage stabilizer block is burned;
(2) the primary or secondary windings of the main transformer are ignited;
(3) the connecting cable between the pulse width modulation circuit and the final push-pull driving transistor is broken or the plug seat is in poor contact;
(4) The outputs of the two arms of the final push-pull drive transistor circuit are seriously mismatched.