UPS - connected to battery plant - repairable?

[new_user]

We have a UPS that was plugged into a -48V DC power plant. Something obviously blew when the 2 charging systems collided. There are no noticeable component issues inside the UPS, but it will not turn on. When plugged in, you can one of the relays click, but no lights on the front panel.

What would have likely happened when those 2 charging systems made contact?

Could a system board be replaced, or is it not likely to be repairable?

Thank you.

 

[Resqueline]

When connecting two high voltage high capacity battery banks, or one such to equipment containing large electrolytic capacitors (like UPS'es) it is preferred to connect them via an equalizing resistor before doing a direct connection. This is to avoid high current spikes from flowing which causes sparks, blown fuses, semiconductor damage, and possibly burnt PCB tracks.
First check for blown automotive style fuses inside the UPS. They may be socketed or soldered directly to the main power PCB.

 

[new_user]

When connecting two high voltage high capacity battery banks, or one such to equipment containing large electrolytic capacitors (like UPS'es) it is preferred to connect them via an equalizing resistor before doing a direct connection. This is to avoid high current spikes from flowing which causes sparks, blown fuses, semiconductor damage, and possibly burnt PCB tracks.
First check for blown automotive style fuses inside the UPS. They may be socketed or soldered directly to the main power PCB.

You can hear a relay click when power is connected, so I think it is making past any entry fuses. This should have never been done, the UPS has an internal charging system, and the power plant is charged by a rectifier.

It is my understanding the DC breaker tripped after a loud crack noise. The system board and components however looks fine.

Thanks.

 

[Resqueline]

There's not much more I can say from the information given. Is the UPS a 48V unit? Was the polarity correct?

 

[new_user]

There's not much more I can say from the information given. Is the UPS a 48V unit? Was the polarity correct?

The UPS was not designed to connect to the battery plant. It had an external connector on it for an extended run-time module. The battery modules are 12V batteries, in series to create 48V. The polarity into the battery plant was correct, but it should have never been connected to it. The UPS is trying to charge it's batteries, and the plant does as well, so these 2 power sources must have collided.

I was trying to see if the UPS would be repairable, and in the above instance, what would be the most common issue to have happened given the circumstances.

Thank you.

 

[Resqueline]

I'm still not certain what voltage the UPS is made for, although you seem to be telling me it's 48V.
An extended run-time module is an external battery bank (although w/o a charger). What is the manuf's recommended connection procedure for those?
Chargers can be connected in paralell w/o catastrophic results, so that's not the problem here. Were the internal batteries run-down before the connection was made?
A loud crack noise followed by a breaker tripping could suggest a considerable battery voltage difference and hence a high current spike flowing.
I have already referred to the most common issues. Thinking all fuses are ok because a relay is clicking is not good enough.

 

[new_user]

I'm still not certain what voltage the UPS is made for, although you seem to be telling me it's 48V.
An extended run-time module is an external battery bank (although w/o a charger). What is the manuf's recommended connection procedure for those?
Chargers can be connected in paralell w/o catastrophic results, so that's not the problem here. Were the internal batteries run-down before the connection was made?
A loud crack noise followed by a breaker tripping could suggest a considerable battery voltage difference and hence a high current spike flowing.
I have already referred to the most common issues. Thinking all fuses are ok because a relay is clicking is not good enough.

Yes, the battery packs on this UPS are 48V. From my understanding their is no way to disconnect the charging system on the UPS, without some type of electronic know-how and physical modification to the unit. The battery plant I'm referring to is a -48V DC plant that is common in telecom collocation facilities. I'm making the assumption that this should have never been done, and due to the connection, the UPS is no longer functioning, yet all components look fine.

 

[jackorocko]

the UPS is no longer functioning, yet all components look fine.

Guess looks mean diddly squat in this situation because some component must have went bad or the device would still work.

48V to -48V = 96V potential difference, so therefor the potential for a large current to flow was present.