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Sep 08,2020

How To Repair An Uninterruptible Power Supply?

UPS and DC power supplies are important power supply guarantee equipment for enterprises. They can ensure that the computer system continues to work for a period of time after a power outage so that users can save them urgently so that users will not affect work or lose data due to power outages.

Under normal circumstances, where UPS is used, the drawings of the UPS are not saved or kept, so how to overhaul and maintain Uninterruptible Power Supply without the drawings?

First of all, another prerequisite for the use of the census method is to master the testing data of commonly used components in UPs. The main difficulty is that the quality of integrated circuits is difficult to judge. However, there are not many types of integrated circuits in uPs. If commonly used models can be prepared, the problem can be solved by comparison or replacement during maintenance.

Line interactive UPS

Statistics based on a large number of maintenance practices show that the components in the UPS are arranged in the order of failure frequency from high to low as follows: Battery (ie, the maintenance-free lead-acid battery in the machine, including false results caused by over-discharge or charging circuit failure Damaged), AC incoming circuit (including fuse, varistor, power switch, etc.), inverter tube (including push tube), power resistor, sampling transformer, small and medium power diodes and transistors, integrated circuits, adjustable resistors, relays, Electrolytic capacitor, low power resistor, main power transformer.

Therefore, when repairing damaged uPS, if you can't find the circuit drawing, you can go directly to the machine to find the fault. While investigating suspicious components, you should also pay attention to checking for some false welding and false welding faults. Generally, the comparison method (compare with good components) and replacement method (replace with good components) can be used for judgment. As long as the UPS has no man-made failures (Offline UPS) and adjustment failures, it can generally be compared to Solve the problem quickly.

The second method is the replacement method, because it is difficult to find the maintenance drawings of the machine, and it is difficult to find the fault with the on-road measurement judgment method, so the replacement method is used to find the fault.

Uninterruptible power supply function:

When the grid voltage is normal, the mains voltage is supplied to the load after being stabilized by the UPS. A good-performance UPS itself is a good AC voltage stabilizer, which improves the power quality; at the same time, it also charges the battery in the machine to store backup energy.

When the grid voltage is abnormal (under-voltage, overvoltage, power failure, interference, etc.), the inverter of the UPS converts the DC power of the battery into AC power to maintain the power supply to the load.

UPS automatically switches between grid power supply and battery power supply to ensure an uninterrupted power supply to the load. And can choose the tolerable switching time according to the precision of the equipment.