Can I get 120v single phase off a 3 phase generator?

[123weld]

I'm wanting to get a generator thats 3pH. It's important that I have 120v single phase to run my small tools. Anyone know if this can be done? If so, can you explain how?

[Jim Rankin]

Depends on the voltage of the 3 phase if you can get it direct or have to have a transformer.

Common 3 phase voltages are 120/208 WYE, 120/240 DELTA and 277/480 WYE. If it's 277/480 you would need a transformer. A small one to run a few tools might not be too expensive.

On either of the low voltage generators, you can get 120 VAC by connecting to a line and the Neutral. On the 120/240 DELTA, there will be a high leg that is 200-208 volts when measured to the neutral. The other 2 lines will be 120 to the neutral, use them.

[bitsnpieces1]

http://www.smokstak.com/forum/showthread.php?t=23666

Try the above link for some info. A 3ph output can be looked at as three seperate 1ph outputs. So you can run 3ph equipment off the three legs and 1ph equipment from one leg and neutral. Hopefully one leg will measure a little bit higher voltage than the other two, use that one to run your 1ph equipment. Are the voltage ratings suitable. ?120 ?240 etc.

As mentioned in the above link you may be ab]ble to reconnect to get 1ph. However, doing that eliminates the 3ph power. The key is whether you have 12 leads available or 4.

[BTPost]

As Jim stated, there are certainly ways to get 120 Vac Single Phase from
a Three Phase Genset, especially when the 120 Vac Loads are small when
compared with the Total Genset Capacity. When you decide on a particular
Unit, post the data off the DataPlate, and we can be more specific, with
our comments.

[J Tiers]

Just as added weight..... your whole house is (probably) single-phase, and is most definitely "running odd 3 phase" right now.....

The power company typically taps a single phase transformer off a 3 phase line, and supplies several houses with it. The next several get another transformer, tapped off a different phase, to equalize the load.

So it is clearly possible.

The simplest way for you will be a 208/120 setup. That gives you 3 separate possible 120V outputs.

Actually, the simplest is a single-phase 120/240 setup, but they are less common aside from the "box store bombs" that will run probably a few hundred hours and then croak..

[Rick Harvey]

JIm Rnaken stated on a delta one side would be higher. NOT on a standard Delta, ALL 3 are the same. If you get a good 3 phase unit, you should be able to change jumpers to get either single phase 120/240 OR 3 phase in either WYE or DELTA. Delta has 3 wires and any wire to any wire is the same voltage (what you set it up for). To get the 120 and 3 phase, I would recommend the WYE which you can get 120/208 (or 240/416 etc) However you set it up for.

I think you are provably using multi voltage motors on your machinery and could wire them for 208 (if not already) If you require 416 or other 3 phase voltage, then you provably need to get a transformer for the small tools.

However if you are wanting to run the house, you need to consider all the loads before you order a generator set.

Just what all are you wanting to run off the generator, and is electric heat involved?

Rick Harvey