Power Distro 3 phase questions

[djbamm1]

Ok guys here is my question that I have been wanting an answer to and the answer I get 99 percent of the time is you should not be messing with that stuff anyway. I have racpac's that Jim at the Ampshop is building for me they have the 50 amp twist locks feeding them(100 total both legs). I tie into single phase 240v with my distro a lot so I feel pretty comfortable doing that. My question is when I am seeing the big boys at these festivals and they have the big quiet run generators with the red,blue,black,white and green camlocks coming out going to a power distro. Now I am pretty shure that is three phase am I correct when I asked one of my Industrial Eletricians at work he said you cannot do that without a transformer. So next big festival I am sneeking around the generator follow feeder cable to the the power distro, 50amp outlets to the individual racpacs. So I ask myself where is the transformer. I want to know this as I have to bid jobs coming up where 3 phase electric is free and you have to pay 100 fee to hook into single phase 200 amp and I also am interested in how they come off of those generators as I noticed they had a tee in the ground off of the generator that went to a ground rod.So is this three phase 208 as you should be able to do it off of that right, just not 480 or am I wrong . So in order for me to buy what I need I would like to be educated on this plus being a small sound company owner I just want to be informed as knowledge is power and these big quys around here wont tell you any info so again to the internet I go. These places have house electricians I just want to know how this stuff works.

[LelandCrooks]

Pay the 100 bucks. You really don't want to be messing with 3 phase, at all. The big gensets operate like a true power plant, with floating grounds, I believe. I run a rental biz, and we rent generators. When somebody wants a big one, I refer them to the specialized generator companies. I know enough to do it, I don't want to. It really needs an expert.

[djbamm1]

Ok that sound good not really what I was looking for but ok.

[pgolde]

The generator is 240v 3 phase with a neutral, there is no need for a transformer. The 240 volts is between the hot legs, all hot legs to neutral and ground is 120v. The neutral carries the current for all three phases for 120v connections.

[Ron K]

3 phase 240Volts 5 wire system.5th wire is ground.

The only way to run 480 3 phase is either through a Transformer or use a freq Drive as the inverter! If you use Freq drives you set the output to 240 Vott 3 phase at 60 Hz. Between the legs you get 220! Very expensive and usually requires the use of big Power Factor Coils to keep the input voltage steady.

There are some amps that will run from 3 phase 208 like the old Crown Macro 10000s.Butt that is a 3phase 4 wire system if I recall.

Note:
Not meant for the OP but for anyone reading this thread
Unless you're a qualified electrician and know how to use a meter correctly you shouldn't be poking around distros! If you dont know the difference between a Delta Secondary and a Y secondary of a transformer you should steer entirely clear! These types of things could ruin your day for real!

[bitSmasher]

3 phase doesn't go ZAP, it goes BANG. An accident with it is not something you generally walk away from

[BillyG]

The best advice has already been given....................Don't do it. Electrical work is not a hobby. If you make the connection and someone gets zapped, you are LIABLE! Let the electricians make the connections and let the circuits down stream become their liability.

[Larry Acklin]

I had an college electrican tie my neutral (WHITE) into a phase once, I inspected, and caught it before we powered up.
They had 3 phase wye 200A with lugs, we tied into 2 phases, and never needed any 220. Until that happened, I was good with that arrangement, but that got me thinking...

I had the venue install a 50A 240V range plug (4 wire) to prevent that from happening again.

Larry