3 Phase 208 Feeder / Single phase 208 UPS / Three phase IPP panel
3 Phase 208 Feeder / Single phase 208 UPS / Three phase IPP panel
(OP)
So I only threw up at least twice today. One of the projects I took on recently was getting our plant UPS systems functioning again. We had an old 3 phase 208 to 3 phase 208 UPS system that had been on bypass since 1999. Parts or repair were out of the question as the manufacturer is out of business. We managed to get the old UPS bypassed a second time and get the original bypass power turned off and the unit out. When we went to install the new unit, much to my suprise its a single phase unit. Of course I went back to my notes, yep 3 phase, the qoute says 208/208, but does not say single or three phase. We have not put any power on the unit and the vendor has admitted that yes I asked for 3 phase. So here is the million dollar question. Can I take 2 phases to the new UPS. Come out of the UPS and feed my IPP panel with Two phases. Note that there are only single phase loads on the IPP panel. Then in the IPP panel take the leg I have identified now as the low current leg and split the load on it between the two phases by doubling up and abandoning that phase in the panel? Did I mention I'm sick.
If the ID is larger than the OD then the whole is on the outside Right?






RE: 3 Phase 208 Feeder / Single phase 208 UPS / Three phase IPP panel
hi there!! have you tried "phase converters"? Check them out, they might be applicable and helpful in your situation. Regards
RE: 3 Phase 208 Feeder / Single phase 208 UPS / Three phase IPP panel
You loads are probably 120V. The UPS output is 208V line to line. How do you plan to get 120V? Technically you will need a 208:240/120V tranformer with 240V side center-tapped to get 120V.
Practical solution: The load was on bypass for years, so what's the difference? Place the thing back on non-UPS power and have the vendor change the UPS and get the right one. In fact regardless of who made the error, the right way is to bite the bullet and do the right thing.
RE: 3 Phase 208 Feeder / Single phase 208 UPS / Three phase IPP panel
If the ID is larger than the OD then the whole is on the outside Right?
RE: 3 Phase 208 Feeder / Single phase 208 UPS / Three phase IPP panel
There must be a wirig diagram in the manual which came with the UPS system, what dose it show?
RE: 3 Phase 208 Feeder / Single phase 208 UPS / Three phase IPP panel
If you connect it to two phases of a three phase panel with no neutral, the panel will not magically develop a neutral complete with the 120 degree phase displacement that is inherent in the 120/208 volt three phase system.
What will happen is that the loads on one line will be in series with the loads on the other line. The voltage from the neutral bar to each line will be in inverse proportion to the load on that line. The voltages will vary as the loads vary, and will sum to 208 volts.
Don't do it. The condition is called an open neutral and will supply over an voltage to the equipment on the lightest loaded line.
respectfully
RE: 3 Phase 208 Feeder / Single phase 208 UPS / Three phase IPP panel
If the ID is larger than the OD then the whole is on the outside Right?
RE: 3 Phase 208 Feeder / Single phase 208 UPS / Three phase IPP panel
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: 3 Phase 208 Feeder / Single phase 208 UPS / Three phase IPP panel
Don
RE: 3 Phase 208 Feeder / Single phase 208 UPS / Three phase IPP panel
If the ID is larger than the OD then the whole is on the outside Right?
RE: 3 Phase 208 Feeder / Single phase 208 UPS / Three phase IPP panel
BTW they often have some excellent referbs for sale that cost a fraction of the new price.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com