Seeking advice from UPS

It shouldn’t be the case; larger UPS units should come with an external bypass built in

If you use a regular commercial machine, it’s as you understand it; the specifications are meant to refer to industrial machines. In Shandong, it’s required that such machines be replaced. The control systems usually have dual power supplies, and you can simply replace both of these supplies with UPS units – you’ll need two UPS units.

1. The main power supply and bypass power supply of the UPS should be powered by different busbars, as shown in the figure. 2. The control system should be powered by a dual-UPS setup, rather than simply combining the UPS outputs together. Instead, two sets of UPS are configured; the load can be switched between the sets, allowing them to handle the entire load. A. Due to the inconsistency in the phases of 220VAC, they cannot be connected directly together ； B. In the past, two UPS units were used together by adjusting their phases, with the aim of ensuring that the system would still be powered by a UPS in the event of a failure of one of them. However, due to improper design and irregular use of the 220V supply at the site, short circuits occurred, resulting in both UPS units failing and the equipment coming to a stop. Later on, both CNPC and Sinopec required the UPS units to operate separately. 3. Currently, the standard control system operates with two UPS units, providing separate power supplies; the 24VDC supply is ensured through a dual-power source and diode modules, thus achieving redundant power for 24VDC ； All components such as controllers, cards, safety barriers, and field 24VDC power supply devices are equipped with redundant power supply ； B. For 220VAC equipment, such as certain nuclear level gauges, servo level gauges, analyzers, etc., a single UPS provides power; however, if critical loads are involved in device interlocks, redundant 220VAC power is required, and a quick-switching device can be installed as appropriate ； 4. The reliability of current UPS systems is relatively high; when the rectification and inversion units fail, the system automatically detects this and switches to static bypass mode ； When a UPS fails and needs to be taken out for repair, it can be manually switched to the maintenance bypass, or all the load can be transferred to another UPS.

Asking the original poster: Which brands are popular these days? Even if the brand has a low failure rate? We have used APCs; there are two sets of batteries, and both sets need to be in good condition for it to work. There have been instances of unexpected shutdowns, but restarting resolved the issue. I’ve used the Suntech model; its modular fan stops working once it breaks, and its display screen fails after 7 years of use. Online replacement is not recommended. I’ve used Corsair products; the circuit board failed at one point, and the display screen lasted 3 years before its contrast level dropped significantly

In ordinary factories, there are different busbars for power supply, and these busbars come from separate transformers; this way, a failure in one busbar does not affect operation. The AEG and Schneider ones we use are good

Could you draw a schematic diagram? Please advise