Can members give their views on the following points regarding UPS supplies: -

What is the 'best practise' for feeding the UPS bypass switch?

If 'A' & 'B' supplies are available, should the bypass supply be fed from the 'A', or the 'B', supply?

If two UPS are utilised one on either supply, should the bypass be fed from the 'other' supply?

if the alternate supply is adopted, does this risk reducing the availability of the supply?

Assume that you mean internal bypass and not external.

The supply and bypass can be taken from the same supplies if required, in normal UPS (3 phase syatems) the output is run in syncro with the bypass supply and the supply and bypass are taken from different supply points. In normal run the supply feeds the unit and the bypass is open, if there were a large current requirement then a static switch would close and the bypass supply is used to clear the fault.
On power loss the battery supply is used in preference to the bypass supply until low voltage is detected and then the bypass supply is brought in (if available).

As to what supply you use to do what that is a matter of design but if you have 2 supplies available from different boards then use one as duty and the other as the bypass feed.

Hope this helps

You could have a maintenance by-pass fed from the opposite side of the board feeding the UPS. Therefore, when maintenance is carried out on the side feeding the UPS, you could run the UPS supplied distribution board from the B side (although not through the UPS for this duration).

Hi
I'm a UPS with the following characteristics:
30kva/720Vdc The middle+360 -360 /
After installing the device on the opposite phase of the AC BYPASS error was encountered. Sequencing phase change but I did not fix the problem.
Battery mode during a power outage in the reverse phase sequence error is recorded.
Three-phase to three-phase system with 60 batteries that are connected in the middle of the UPS.
The device is working properly and charge mode and battery power supplies.
But the error is detected.
Please help me!

Try this. (safely)

Measure the voltage between the two supply phases with a simple voltmeter, you should get somewhere approaching zero vaults between like phases, and phase voltage between unlike phases.

If you get too many volts (say greater than 9) between the supply phases that you think are in phase, then they are likely not in phase and you cannot common them up through the by-pass.

Do you have a neutral?

Thanks for the guide.
But the voltage between approximately 370 to 380 volts phase to neutral voltage and phase Input 200 to 210 V, which is right after.
If the phase sequence is difficult because of the power outage and when the unit is running on battery even bypass the phase error is observed in Twi?
This is due to the displacement of nearly two months off. Now on the output power and battery but the error I mentioned on the left.
Do I need to install the software is? Automatic phase sequence or the device is broken?

Hello guys....


Nice suggestion and guiding for us.