I need help understanding AC electricity and generators (1/3 phase)

[fatjay]

I have googled and googled over the years and have come to a limited understanding on how things work. I will go down the list of my current assumptions, if I'm wrong please correct me.

I currently have a generator that is 10kw 110/220v. In 220v mode i have a ground, neutral, and 2x 110v's 180 degree's out of phase. These 2x 110v's go to the 2 busses in my breaker box by way of a 50a 2 pole breaker. When the power goes out, I switch off my main, switch on my generator, and I can use electricity, both 110v and 220v devices.

There's many generators on craiglist that are 3 phase. From my understanding, it's 3x 110v's 120 degree's out of phase. Being that my breaker box is only 2 phase(i know hte terminology is wrong, but i don't know the right way to say it), I would only be able to utilize 2 of the 3 phases available from the generator. So 15kw becomes 10kw. However does putting those 2 phases together create a usable 220v? I'm guessing no. Which means I wouldn't be able to utilize any 220v appliances in my home.

Why is a 110v/220v generator called single phasea nd not 2 phase? It provides 2 phases of electricity capable of generating 220v? They're definitely distinct from generators that only provide single phase 110v.

I realize that some of this I am not even asking the right questions, so please be patient.

 

[Industrial Toys]

The 110 and 220 are not out of phase. They are just different windings either from a stator or transformer. Three phase legs ARE 120 degrees out of phase.

There has been much writeen here about using three phase generators for single phase. It gets very complicated.

My take on it. You can use many three phase generators for single phase at a reduction in capacity, some better than others. I would say, that's ok in a pinch, but I personally would opt for a single phase unit when requiring single phase.

 

[fatjay]

So the 220v is 2x110v of single phase?

The reason I want to learn more is because at 10kw I’m generating just under what I want, I’d like to go 20kw, but I’m having a hard time finding anything that big that isn’t 3 phase or propane, and I’d prefer diesel since I have diesel tanks but no propane.

 

[Industrial Toys]

I am a fanatic. Have three slow running Diesel sets 7.5KW X2, (one inverter, one conventional) a 12.5KW and 3.7KW Air cooled Yanmar Screemer.

I'm always amazed at what people THINK they need. The smaller set I can operate, the better in my opinion. I run all these little guys into a 200 amp ASCO auto switch. No one says you can't do that.

AND YES, people often refer to the two phases in a single phase panel. Wrong! Leg might be the better term.

 

[Roadworthy]

To further muddy the waters, if you have three phase 208 you can go phase to neutral to get 120 volts. There is really no way to get single phase 240 out of it though - other than to use more equipment. Your best bet is to just get the equipment you need.

 

[Grumpycat]

25 years ago I ran a computer center which had a 50kW Liebert 3-phase UPS. However the electricians wired the output as 3 zones of 208 with neutral so 120V devices would operate.

It was a beast with something like (109) 12V group-27 sized lead acid batteries.

 

[Topzide]

Check out Generator Accessories – Gas Generators | Central Georgia Generators
They have pto kits for use with tractors and stand alone units. 21kW - 25kW units with 3 - 4 week lead time

 

[Carl_NH]

So the 220v is 2x110v of single phase?

The reason I want to learn more is because at 10kw I’m generating just under what I want, I’d like to go 20kw, but I’m having a hard time finding anything that big that isn’t 3 phase or propane, and I’d prefer diesel since I have diesel tanks but no propane.

Why do you need more than 10KW @ 240VAC? Its easier to reduce load and only power what you need in an outage. I understand if you want to run AC, and hot water, a well pump and the rest of the house at the same time you will need 12-15KW to meet peak demand, but if you can manage/reduce the load to what is needed that's preferable.

As Topzide suggested there are PTO driven generators that one of your tractors can run that generate 12-15KW and you will need 20-25 PTO HP roughly to run these. Your B8200 is a bit light at 15PTO HP.

 

[fatjay]

10kw @110vac, 5kw @220vac, 50a 220v breaker. I run a server rack with many computers and servers in the basement for work, wife likes ac and hot water. The goal is minimal interruption during power outages. Working from home, kids are attending virtual school this year. We lose power regularly.

I'd rather not tie up a tractor, I'd like a dedicated machine. I'll buy/build whatever i need within reason, just want to learn what I need to do it right.

 

[Industrial Toys]

My first genny was a pto 15KW Onan. Great machine, but un-nerving having your tractor run full tilt unattended. And at night, for what? to run the fridge?

I run my hot water heater at half power. Less lime deposited on the element and half the load to worry about in an outage. I have never un out of hot water, but I mostly live alone except for weekends.

I kind of WISH, with all my resources, that I lost power regularly. Also have a 3000 watt telecom style inverter. 48 volt input that I "intend" to plug into my E-Gator one of these days.

REALLY, the trouble is not so much loss of power, as never knowing how long it will be out. The modern IT systems to keep you informed are worth nothing and getting worse as they get more complicated.