| Author |
Message |
Matt (Hgtech)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, June 13, 2006 - 4:57 pm: | |
Hi everyone, I've got a question about hard wiring the generator on my bus. The question is simple, but I'll tell you a little about the generator before I ask the question.
First of all, it’s a Chinese made piece of crap. Don't ever buy one of the cheap diesel generators off eBay even if it's the only thing you can afford. In less that four months, the stop solenoid and the starter have already committed suicide, the manifold seal is leaking, and a weld on the muffler has cracked. The total run time on the generator is probably 400 hours or less.
Anyways, here's the deal with the wiring. First, the generator is 5500watt - 5 wires. It has two 20amp legs each with a positive and a neutral. There is a common ground point for both legs. This gives me a total of five wires (2 positive, 2 neutral, 1 ground). My electrical panel is only designed for four wires (2 positive, 1 neutral, 1 ground). So, here's my question. If I connect the neutrals together in my electrical panel, is it going to fry something in the generator? Every generator I have ever worked with has been a four wire, not five. Any advice would be greatly appreciated. I marked this urgent as I am leaving town for a week with the bus tomorrow and would really like to finish this up by then. Thanks!!!
Matt
1979 Silver Eagle Model 05 |
Brian Brown (Blue_velvet)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, June 13, 2006 - 5:51 pm: | |
Matt, yes you can gang your neutral legs together at the panel.
Be sure and buy a grounding bar kit for your elec. panel and keep grounds and neutrals on their own bars. Unlike a house system, the neutral is not to be bound to ground at the panel, but at the genset, origination of shore power, and inverter.
HTH,
Brian Brown
Longmont, CO |
herman
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, June 13, 2006 - 6:26 pm: | |
Hmm, I wonder how this critter's voltage regulator wired up?
Anyhow, it sounds like you have two seperate 120V windings; checking them with an ohmmeter (genset off) should show a small resistance (that of the winding) between each hot and its corresponding neutral, and an open circuit in every other respect, i.e. between windings (hot1-hot2, neutral1-neutral2, hot1-neutral2, hot2-neutral1), and between ground and all hots & neutrals.
If the above is indeed the case, then you can wire them in either of 2 ways:
A) in series, which will give you 120/240V service, e.g. 20A @ 240V or 2x 20A @ 120V or the various mixed cases thereof. This resembles the standard 50A 120/240V, 3 pole, 4 wire, RV shore service, but at reduced ampacity.
Do this by connecting one winding's hot to the other winding's neutral, e.g. H1-N2; this becomes the output neutral, and the two free winding wires, H2 & N1, become the output hots. Bond the ground wire to the chassis, as well as to the output neutral (the H1-N2 joint) and to the output ground wire. Put a 2 pole 20A breaker at the genset to feed the main panel.
B) in parallel, which will give you 120V @ 40A service. This resembles the standard 30A 120V, 2 pole, 3 wire, RV shore service, but at increased ampacity.
Do this by connecting H1 to H2 and N1 to N2; this gives you an output hot and an output neutral, which feeds a single pole 40A breaker at the genset; feed this to both hots of the main panel. Bond the ground wire to the chassis and to the output neutral (the N1-N2 joint), and to an output ground wire.
An alternate parallel approach is to just join N1 to N2 (this joint becomes the output neutral) and then treat everything else as per the series case; you'll have only 2x 20A @ 120V. Because the hots are not interconnected, you will have to manually balance the legs and will not be able to support any single load that draws more than 20A. You will also have to size the output neutral conductor for 40A, whereas in all other cases it is a 20A line.
Note that, for either of the 120V only cases, the main panel should contain no 240V loads, i.e. no 2 pole breakers (other than, for the 2x 120 case, the optional service entrance breaker from the genset, if you are not attaching the genset hots directly to the panel's lugs or if the panel has no main lugs).
Question: do you actually want your main panel to be fed by nothing but this genset, vs. e.g. also shore power? |
Richard Bowyer (Drivingmisslazy)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, June 13, 2006 - 6:35 pm: | |
The ground is normally not considered one of the wires of an alternator.
Based on that I suspect you have a four wire alternator. Typically they can be wired for 120 volt output or for 240/120 volt output.
For 120 volt output only, you connect leads 1 and 3 together and leads 2 and 4 together. Either of the connections can be your hot or neutral.
For 240/120 volt output, you connect leads 2 and 3 together. This is the neutral lead. Leads 1 and 4 are the hot leads.
Please remember this is standard wiring for an American made alternator and may not hold true even on all American made units.As I recall the Onan may have a 30 amp and 20 amp output which can not be connected together.
If the leads are not numbered L1, L2, L3 and L4' let me know.
Be very careful if you try experimenting. You can permanently damage the alternator head. I would use 5 amp circuit breakers in any jumpers used to connect the leads together.
Richard |
Richard Bowyer (Drivingmisslazy)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, June 13, 2006 - 8:58 pm: | |
Post in error
(Message edited by drivingmisslazy on June 13, 2006)
(Message edited by drivingmisslazy on June 13, 2006) |
Richard Bowyer (Drivingmisslazy)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, June 14, 2006 - 5:15 pm: | |
testing post. Everything seems to be wroking properly now
Richard
(Message edited by drivingmisslazy on June 14, 2006) |
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