Data Center Battery Ground Bus
Data Center Battery Ground Bus
(OP)
So a contractor says he measured about 80V AC on the DC battery ground bus (I believe it is 48VDC battery system) for a good size college data center. I'm not sure where the reference for the measurement was made. Anyone ever heard of something similar??






RE: Data Center Battery Ground Bus
NOTE: When 'Data Center' and 'Batterie' are uttered in the same sentence you better be very careful with even tests like that above, as some ground fault system could trip killing your data center.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Data Center Battery Ground Bus
RE: Data Center Battery Ground Bus
Hmmmm
First what type of UPS is it ? 48v DC seems a little light for a good sized data centre.
Need to know what UPS you are running, then take it back from there, if you are running a motor gen set type then the thristor driver for the motor may be imposing an ac waveform on the dc link - this would be a duff connection but a good ups would alarm due to this - why was it being checked do you have a problem with it?
RE: Data Center Battery Ground Bus
Somebody had modified one of the units to be a motor starter. In the process they re-wired about half of the control panel to run from the local control power transformer.
Typical sloppy practice, they didn't clearly differentiate between the "return" side of the DC ladder logic diagram and the "neutral" side of the AC ladder logic diagram. They were tied together somewhere in the rat's nest and that made the control power bus for the entire lineup hot.
The "neutral" AC leg was actually one side of a 240V secondary with a grounded center tap.
RE: Data Center Battery Ground Bus
Rugged