Most all 480v feeders in commercial and industrial applications nowdays are connected as Y, there are a few exceptions as in mining and older plants that still use some 480 delta connected equipment at least in this area. Don't know what power company you have there(probably Duke?), but they most likely use the American Standard transformer connections as do most larger companys. You should have 480volts phase to phase and 277v phase to ground on a Y system. You get 480 by multipling 277 X 1.73 (sq. root of 3),=480. Same thing on a 208, 120 x 1.73 =208. Most delta connected systems will have a high leg,(a phase that has a higher voltage measured to the neutral or ground). You will still get the needed voltage phase to phase(usually 240) but the high leg will sometimes have double the voltage(phase to ground) as the other two phases due to the way it is connected at the transformer.Hope you get some training on 3 phase electrical systems and connections, be careful, you could have a China Syndrome in your face grounding out that 480.......

 

it seemed easy to my friend, just took a while. the wires were just bolted together. at least i now have something i can use. hard part was redoing the gauges to know what was going on. converted engine to propane so now i have no fuel storeage problems.

 

Here's one that looks pretty good and not too heavy on the math end..

http://www.allaboutcircuits.com/vol_2/chpt_10/2.html

I'll post some others as I find them...


Keith

 

Being a diesel nut, I have been wanting to find a good diesel powered generator to replace my old Onan 5kw CCK powered unit. The Onan has a gasoline/LP carburetor but now since I sold my old Chevy gasser, I don't have any reason to use gasoline anymore.
LP is ok, but I would love to have a small Kubota powered 8kw generator that I can connect to my Dodge's fuel tank and run for an extended time on its 35gal tank. (thinking hurricanes here)
There are some good buys on generators out there but they are 3ph ONLY! non-reconnectable to 120/240 1ph. Gotta watch out for those unless you NEED 3phase power!
The secret is to find a 3ph unit that says, "12 wire, reconnectable". Those have sufficient winding connections to reconnect the 3phase generator end to deliver full or close to full rated power while connected for single phase 120/240vac operation.

On the 3ph link, note what they say about partial failures on a delta and wye systems. Note that the Delta has some "redundancy" built into its very nature. (US NAVY etc)
WV SMOKER is right. Most "modern" (<30yrs old) industrial plants have gone to Wye connected transformer systems. Some of our sister plants still have the old grounded Delta systems.
Our plant brings in power at 138Kv from local CoGen plant. 138kv to 24kv transformer(delta primary xfmr windings) provides the intermediary distribution voltage of 24kv delivered thru an underground "loop feeder" around the plant. From there, 24kv(delta primary) to 480v Wye transformers feed virtually everything on-site.

K.

 

The only China Syndrone I'm gon'a have is when the move my job over there. Sorry
When we're working on these things the power is cut off and double checked with a meter before we start. These things have either fuses and a contactor or are driven by fused inverters.
That looks to be a very good site to read up on. Made it through the first page tonight but I really need to get in bed so maybe some more tommorow.

Thanks for all the input. You guys are great!