no power 804b

[jlxb]

Hi, I am not an electrician but I see some things in the photos that may be significant.

1) In the photo I see that L1 +L2 is reading 208 volts. That would be correct if the genset was still set up (wired internally) as a 3 phase generator. That means that L1,L2 and L3 are all hot with 120 volts each
2) At the connection studs, your electrician has a white wire connected to L1 - Red and Black are connected to L2 and L3 respectively. Three hot wires are never used to supply single phase power.

Conclusions:
A) Your generator is NOT set up for single phase
B) The White wire is supposed to be neutral in a single phase scenario and L1 is NOT neutral. This is very dangerous! That white wire goes to neutral in your main box in the house but the electrician has120 volts going into neutral. Put a hand held meter on it to verify.
C) The electronic contactor will not stay engaged because it detects the fault condition - the fault is an over voltage (208 volts instead of 120 L to neutral) on the outside of the contactor.

To remedy this follow these steps:
1) Take the green wire off the ground stud and attach it to the earth ground stud on the outside frame of the generator
2) Take the white wire off the L1 stud and attach it to the L0 stud one position to the left. It is now neutral.
3) You can leave the red and black where they are or move them both over to the left, it does not matter.
4) Make sure you have the genset well grounded to earth with a grounding rod.

In this configuration, you are pulling single phase off of two legs of the three phase generator. You will only get 2/3 of the generator this way but that is OK. You have 10Kw available.

 

[Guyfang]

jlxb,

You could be right. BUT, you are assuming that the cable goes to the house. In the paragraph below, taken from the first posting, I highlighted a sentence. If I take the man for his word, and he indeed wrote what happened, then that might not be the case. It could also be that the electrician had some type of load bank to test the set with. I will admit, over the last 40 years to hooking up stuff, with no regard to wire colors, when I was doing the hooking up, I was doing the testing and I sure unhooked the mess when I got done!

Afternoon. I am sorry if this has been posted, I could not find it. On the surface this question seems simple to me, but likely more complicated than expected. I picked up a MEP-804b genset with 46 hours on it a couple of months ago. Finally got the house and generator wired by an electrician that mostly does generators. He wanted to do a couple of checks before connecting to the house to avoid any possible damage. When I flip the switch to the closed position he gets the appropriate volts, amps, whatever in the wire, but the switch does not stay in the closed position. When I let go of the switch it returns to the mid position and no more electricity. Is this a 3 position switch that is supposed to stay in the closed position? If not, will the circuit remain closed if I have the generator connected to the house/load? Courtesy plugs work fine. It is wired single phase. Thank you for your insights.

The original problem was the CB-1 will not stay closed Several people suggested that the load be disconnected, to see if the problem was in the set. Or in his hook up. I haven't seen an answer to that question yet.

If that was a load hooked to the set, the green wire indeed goes on the load terminal shown. Never hooked to the the outside, on the ground stud. It would not fit, in any case. The ground/neutral strap needs to be removed, or not, the jury is still out on that, but as for the other wires, maybe they were only hooked up for testing? I cant answer that question.

 

[jlxb]

Guyfang,

Like you, my wiring may not conform to standards. But I have not assumed anything. Evidence from the photos indicates that this generator is in 3 phase mode while the owner says it is wired single phase. These things contradict each other. The question was posed earlier to find out what the owner meant by wired single phase but there was no answer. The photo of the wires show three wires connected to HOT legs. Three hot legs are never used in a single phase arrangement.

If CB-1 detects a short circuit condition, it WILL NOT stay engaged. This can also be caused by a bad or missing solid earth ground.

 

[Guyfang]

jlxb,

All true. IF that cable went to the house. Let's wait to hear from the horse's mouth. And, if he unhooked the power cable to see if the set worked. If that was done, it would be a sure sign that the hookup was wrong, or not?

 

[Delmd92]

See, this is why people like me should not be allowed to own nice things. I thought I had done enough research on using this generator single phase and could find no reason not to. I wanted something in the 15k range to just use for the whole house and not have to pick and chose what got power durning an outage. Planning more for worst case scenario than simple storm damage. More in my next post.

 

[Delmd92]

Sorry about the long delay in getting back to the forum. Too many number one projects to complete I guess, oh, and that work thing. I reviewed the manuals that I have found, for their respective trouble shooting sections and then reviewed the solutions. Frustrating to a noob like myself that some of them say "refer to the next higher manual" but then there is no mention what that manual is. I double checked everything at the generator. I was never able to hear the clunk despite testing several times. I was not able to get the light above the switch to work like one of the manuals said I should do during testing, but the light works just when I test it. Ended up talking to someone I know who a Guardsman and as it turns out the generator is his job when they drill. He doesn't know much about the mechanicals though. Ground rod, ground rod, ground rod, he said. Not allowed to do anything with the generator until the ground rod is in place. So I added one of those. A day after this, my son was coming home, the electrical engineer. In anticipation of his being home for the weekend, I had him doing some research as well, since he did not know anything about military generators. He went over things carefully and we tested things before restarting the generator. Followed the directions on startup and when up to operating temps, flipped the switch and wouldn't you know it, perfection! Mostly. There is a bit of flickering of the lights, but the power seems to flow smoothly when he has his meter on it. Unloaded we are getting 220v at the studs and when testing the single legs getting 127v. He tells me that is ok and will likely drop as more load is added. He is coming home this weekend again and I will go over some of the new information with him, thanks for that extra wiring information.
He ran calculations on most of our appliances and the well pump, really the biggest motor that I was worried about damaging. Manufacturer said had to be 240, not 239, not 241, but then when you get the manual and read the parameters, it will work at 208 and has a built in thermal protection to shut it down before damage occurs. Hard as we tried, we could not get the load meter over 40%. My Guardsman says they are happiest between 60 and 75%, I do not know how I will get it there for the time suggested to run these things. Spiked to 60% when a motor kicked in, but mostly maintained 20-30% after the initial spike. (Oven, stove top, 2 refrigerators and 2 freezers and a few assorted lights. Not much left in the house to turn on.) Now it looks like the oil pressure guage is bad. Condensation behind the glass and pegged far right (at least at my house that is acceptable). Have not had time to research that in the manuals yet.
Not sure if the ground rod was the solution or having the boy around. Since little, he has been able to make computers and electronics bend to his will. Even if I do everything he tells me to do, it doesn't always work until he is in the room. Makes the rest of the family feel inferior. Haven't tried things out since he was last home, trying not to jinx things. I will have to eventually, since I can't count on him being home when the emergency hits. Thanks again everyone, this has been hugely helpful and reassuring. Love having a community who knows their stuff.

 

[155mm]

I would not be overly concerned about the imbalance, if you are concerned then just rotate your load leads every few hours, days. or look at those halogen shop lights on a stand, they pull about 1300 watts for the pair, just hook that up to the unused terminal.

If you havent read this, this is my thread for an 804a running 2 legs of 3 ph for 7 days with no issues and we didnt short ourselves for anything. We ran like we were on line power. https://www.steelsoldiers.com/showthread.php?167498-Wife-is-now-a-green-iron-believer&highlight=

 

[jlxb]

If you havent read this, this is my thread for an 804a running 2 legs of 3 ph for 7 days with no issues and we didnt short ourselves for anything. We ran like we were on line power. https://www.steelsoldiers.com/showthread.php?167498-Wife-is-now-a-green-iron-believer&highlight=

A few years ago sewerzuk put together videos showing how to reconfigure the MEP 004A to zig zag single phase. Does anybody know if the same thing can be done with the TQG series?

 

[Delmd92]

I have a few of those lights laying around, maybe I will try them next time I fire up the generator. My son is also looking into a 3 phase to single phase converter, that way I wouldn't need to rotate and I would get the full power of the generator. If there is a long-term need though, I suspect the neighbors will find a way to help out with keeping the power usage in the 60-75% range.

 

[155mm]

A few years ago sewerzuk put together videos showing how to reconfigure the MEP 004A to zig zag single phase. Does anybody know if the same thing can be done with the TQG series?

.

That can NOT be done with an 804, 805, or 806, reason being, those genny's are only 10 wires from the generator head, 12 wires is required for the zig zag.

I am not yelling, just dont want to see good equipment let the smoke out.

 

[155mm]

I have a few of those lights laying around, maybe I will try them next time I fire up the generator. My son is also looking into a 3 phase to single phase converter, that way I wouldn't need to rotate and I would get the full power of the generator. If there is a long-term need though, I suspect the neighbors will find a way to help out with keeping the power usage in the 60-75% range.

in our country out here, there are lots of rotophases that convert single to 3ph, I have always wondered if they would work backwards, and how efficient they would be if they would work backwards.