I have a 9k diesel genset which produces 120/240 volts. I only have a 120v system and in order to "keep it simple" I plan to use a receptacle to plug the main panel into the genset power and a receptacle to plug the main panel into shore power.
If I run wires from the genset to the receptacle, do the red and black 120 leads get tied together?
The 30amp. plug simply has a black, white and green(gnd.)
Iver.
No- since you have two different windings on the gen for each leg of the 120 to make 240, if you tie in both the red and black from both sides, you'll get a short. Most gens can be rewired for straight 120v 2 wire full output-that's the way my gen is wired, and it is a 10kw. Makes for much easier control of the electrical system since you're not going to be always concerned if the two legs of the 120v are balanced. The only disadvantage is that you can only use one leg of the 50amp power plug when available. But for me, that's enough power, since that is 6,000 watts. I just stagger my electrical usage when parked, and everything gets done. I like the straight wiring, I would do it again. Good Luck, TomC
9K is a lot of power for 120-volt wiring. It's a bad idea to have a genset that puts
out more that 50% above your normal high-end loads.
Diesels, especially, need to be loaded at not less than 60% of rated HP most of
the time. Otherwise, you need to be able to put a big load on them for an hour
or two at least once every 30-40 hours of operation, to prevent glazing of the
cylinder walls. I helped 2 Moms plan their buses so they could cross-connect
both buses, using one as "shore power" for the other. That way they could
get a full load on the genset when they turned everything on for a while. (The
people they got their buses from outfitted them with gensets way bigger than
what they needed.)
I know nothing about your overall conversion, but having 240-volt capability
is never a bad idea, especially if you have multiple circuits from a breaker box
or panel.
Clarke
Our generator is wired for 120 only output. Here are the reasons we went this way. First we have nothing on our bus that requires 240 volts. I was told that if wired 120/240, we need to keep the loads balanced between the 2 legs to within 15-20%. Our basement AC has 2 20 amp circuits so if we connect one circuit t each lag, we are balanced. Until we turn on the water heater, now we are out of balance (unless we always run the microwave when the water heater is on). Then there is the block heater. For us it was much easier to just wire thegenerator are 120 only and not worry about trying to keep the loads balanced. Depending on your loads, YMMV.
A 10 KW generator will give you 5 KW on each leg if wired 120/240. If wired 120 only, you will have 10 KW on that leg. A generator can also be wired for 240 only and that will be 10 KW. Jack
The only real advantage I can think of for going 120/240 is so you can use the generator as a backup fou the house. In my case, we are rural and the water pump is 220.
Len
Quote from: Len Silva on September 11, 2007, 06:24:56 AM
The only real advantage I can think of for going 120/240 is so you can use the generator as a backup fou the house. In my case, we are rural and the water pump is 220.
Len
I solved that problem by installing a 120 to 240 volt transformer at the house. Used it one time for several days when we had a big ice storm. I was the only house in the area with lights on. LOL
Richard
My opinion is that the genset should be wired for 120 volt output only, if you do not plan on any 240 volt appliances to be installed.
I do not feel that 10 kw is an over kill. I run my genset for thousands of hours with generally only 30-40% load and never experienced any problems with it carboning up.
I feel you should wire the system so that you can accept the full capacity of a 50 amp shore cord. Really not hard. Just install a 240/120 volt distribution box/breaker panel and an appropriate transfer switch to change from genset to shore or inverter. This could be either an automatic transfer switch or a manual transfer switch or a manual plug and play arrangement.
In doing this, the system is wired so that both hot legs of the breaker panel receive 120 volts from the genset. When on shore power each of the hot legs of the panel receive one of the hot legs from shore power.
I also recommend putting in a couple of 30 amp buddy plugs so that if you are boondocking everyone does not have to run their gensets> When I was visiting Glamis in the desert regularly I typically supplied two or three S/S RV's with AC power.
Richard
Thanks everyone for your help. I think I will do as Richard suggests and set up a 50 amp service. Probably just as simple and also something with which I am more familiar.
Thanks, Iv.