High voltage with generator running

[78elandan2]

 Hey guys!  First of all I want to say thank you for this forum and the WEALTH of information here.  I'm an extreme noobie! I know next to nothing about motorhomes and it is so much help to sift through stuff here.
     

     After much discussion my wife and I bought a 78 Elandan 2 a couple of months ago.  It's in really great shape and fit our needs perfectly! We camped in it several times in the back yard to familiarize us and the kids with it.
     

     Last weekend we finely got to take it somewhere and had a great time.  There's nothing like the feeling of waking up on Sunday and never getting out of your pajamas to head to the house!!  We did not have hook ups where we were at so we run the generator a little every day.  Saturday we ran the generator for a few hours so the kids could watch a movie and settle down.  While we had the generator running we turned a few lights on.  We had 6 lights blow while the generator was running!  The florescent light actually caught on fire!! We shut the generator off and didn't mess with it.  I was worried about the tv and dvd player, but I installed it on a nice surge protector earlier but it never kicked off.  When I got home I started the generator and removed one of the light bulbs and checked the voltage.  I had 21.76 volts at the light bulbs!!  No wonder so many bulbs blew!  We've never had a problem with this before.       One thing I had to do differently this weekend with the generator is adjust the choke.  When we bought the winne the PO had the generator serviced (they did points and condenser, plugs and wires).  I guess he adjusted it for cooler weather because it was warm this weekend and the generator would start and run for about 45 seconds fine, then load up, start missing, and smoke.  I'm very familiar with engines and it sounded like the choke was closed so I moved the little wire that sticks up out of the choke housing for about a minute and it ran great!!  I don't know what this means but we are wanting to take it more places but need the generator!!
      I'm not sure what generator we have and can't find any info on it.  I know the PO said it was a 6500 watt generator.  I also know it will pull both air conditioners and the microwave at the same time!!  It's worked wonderfully up until now!!  Any help would be greatly appreciated.  We have to run the generator while driving because of running the air conditioners so we're kind of stuck right now.  I do not want to run it in it's current state.  Thank you for all your help!!

[DaveVA78Chieftain]

First, assuming you are referring to the 12VDC lamps, the 21.6VDC represents the output of the converter, not the generator.  So, the first step is to plug the rig into 120VAC shore power and see if you have the same problem.  If so, then it is a converter problem.  To assist with that we would need any information you have off of the AC/DC control center panel.  It most likely a Progressive Dynamics model.

There is a little confusion here at the Winnebago web site.  The 78 brochure (http://www.winnebagoind.com/products/previous-models/1978/pdfs/winnebago/78-ElandanII-bro.pdf) indicates you have D29D Elandan 2 model.  They only list (http://catalog.winnebagoind.com/menu/Parts.htm) a D29D model parts list for 77 (http://www.winnebagoind.com/service/wincd/1977/77wd29d.pdf), not 78.  That 77 parts book indicates they used Kohler Generators that year in Elandan 2's.

As far as help with identification of the generator, pictures and any information printed on it may help to ID it.  I have a hunch it may be either a 5.5 or 7KW unit.

Dave

[78elandan2]

I was hoping you would reply to my post. I want to one day do the power distribution and converter upgrade that you did on yours (My converter looks just like yours btw).
The generator is an onan, I know that for sure. When I get home I will check the voltage from the 110 outlets with the generator running and the voltage from the 12 volt lights and 110 outlets with it plugged into shore power. I will also get some pics of the generator and see if I can get any numbers off of it. It must not be the factory generator since its an onan. Thank you!


Gavin

[DaveVA78Chieftain]

If it is a 6.5KW Onan, then it is most likely a NHE model.  You are looking for a ID plate that should be located on the fan shroud like this one:



Need all the information off it for decoding



Yours would be something like 6.5NHE-3CR xxxxx M

Dave

[M & J]

Nice load test you have going on in the background Dave.

[DaveVA78Chieftain]

  - random picture off the net to demonstrate the location.  I did notice the load test stuff though.   I suppose he was check each circuit seperately.  I would have moved the "glass can" a little further away from the exhaust pipe though.

Dave

[M & J]

I saw that too. But he did have it in a plastic bucket with what looks like a piece of steel to keep it stable.

[78elandan2]

I got home today and checked the voltage plugged into shore power. I have to add that it's on a 50ft drop cord plugged into a 15amp outside outlet. The voltage at the light inside was 13.73v. I figure that to be about normal. The voltage at outlets is 123v or so. All this sounds normal. I'm starting to get confused. Isn't the converter supposed to keep the converted volts to around 12?
I also looked at the generator. There was no ID plate on the fan shroud. Their was a sticker on there but all it said was workinger inc, onan sales and service. I took some pics of the generator and any stickers on it. The spot on the fan shroud is where the sticker was. I peeled it off to see if there was a ID plate under it. I also took a pic of the carb and choke area. Thank you for all your help.

[ClydesdaleKevin]

That is really odd!  Not the sticker thing either.  Whatever volts come into the converter, it should put out a nominal 120 volts.  If the AC volts coming in are too high it should shut down or trip a fuse or breaker.

Try unplugging your converter and start your genny and test the voltage at the AC outlets.

If its 120 or so, the genny isn't the problem, nor is your converter.

If its way higher than 120 it needs to be adjusted down to the 120 range.

If its 120 or so but you are still getting high DC voltage, a previous owner may have rewired and messed up the genny wiring.  They have the capability of charging you batteries directly when running, but if they are doing that while the converter is putting down a charge, it can almost double your voltage.  So if the converter is putting in 12+ volts, and your genny is putting in a 12+ volt battery charge, you are now going to approach over 24 volts if its wired wrong.

Kev

[DaveVA78Chieftain]

Kevin, I think he is saying that on shore power source:
Voltage at a 12VDC lamp is 13.73VDC (typical converter output)
Voltage at a 120VAC outlet is 123VAC (typical AC voltage)
so,
the issue is with the generator.

That was was the reason I asked him to try shore power before determining where the problem is.

I am culling through my stuff in order to ID the generator.

Dave

[DaveVA78Chieftain]

That is either a 5.0BGA or 6.5NH generator.
A 5.0BGA uses grade 8 bolts to secure the head to the block.
A 6.5NH uses studs and nuts to secure the head to the block so from what I can see in your picture, it is a 6.5NH.

Trying to deduce the NH spec number:
Spec J and earlier only used 1 relay and did not have safety CB's for each 120VAC leg
Spec K and P used 3 relays and did have safety CB's for each 120VAC leg.

Manuals for the NH generator are in or Free members section so join the site and download them.

The cover that directs air over your cylinder head is missing.  You need to either find one of make one to prevent overheating the cylinder.

Dave

[DaveVA78Chieftain]

I should add, once you have the manual, next step is to verify how it is wired into your rig.  Do you move your shore power cable or have CB switch selection to transfer from shore power to generator?

Dave

[M & J]

Looks like there's a service specification label on the genny field housing.

[DaveVA78Chieftain]

What spark plug is in it? Name/model

Dave

[78elandan2]

I do not have a separate plug for the generator or a switch fo flip to change from shore to generator. I just unplug from shore, start the genny, and wait for a beep before i start anything up.
Yes there is a service specification sticker on the right side. I looked for a model number on it and found nothing.
I will pull the spark plug tonight and get the model number off of it. Thank you for your patience and help!

[M & J]

I'm wondering if getting a clear close up pic of the maintenance sticker will help Dave ID the genny.

[DaveVA78Chieftain]

You must have one of the rare Progressive Dynamics Power Centers that had Auto Shore/Generator switch capability (Pre ATS era).  The BEEP should be coming from it.  Complicates things some but not insurmountable.   Protection breakers would be in the Power Center.  I would want to know the model of it though.  And a picture of it if possible.  Will help to talk to it.

Simular to http://www.progressivedyn.com/service_discontinued/PD7500-7700%20Manual.pdf

Wiring diagram on pdf page 28 of http://www.progressivedyn.com/service_discontinued/PDI%20Service%20Manual%20710778.pdf

Dave
PS: For the life of me I cannot figure out how I remember these tidbits!   i??

[bluebird]

That is really odd!  Not the sticker thing either.  Whatever volts come into the converter, it should put out a nominal 120 volts.  If the AC volts coming in are too high it should shut down or trip a fuse or breaker.

Try unplugging your converter and start your genny and test the voltage at the AC outlets.

If its 120 or so, the genny isn't the problem, nor is your converter.

If its way higher than 120 it needs to be adjusted down to the 120 range.

If its 120 or so but you are still getting high DC voltage, a previous owner may have rewired and messed up the genny wiring.  They have the capability of charging you batteries directly when running, but if they are doing that while the converter is putting down a charge, it can almost double your voltage.  So if the converter is putting in 12+ volts, and your genny is putting in a 12+ volt battery charge, you are now going to approach over 24 volts if its wired wrong.

Kev

Wrong,
Kevin you don't add the voltages together. You can actually charge the batteries  from multiple sources at the same time. They will only charge from the highest source. Most newer MH will charge the batteries from the alternator, and when you run the gen, the power converter will be charging also.

[78elandan2]

Little update on this. I checked the voltage at the box coming out of the generator and it was 200vac! I adjusted the idle of the generator to get 125 to 130vac. Everything seems to work just fine now. Voltage at the interior light bulbs is around 13vdc and everything is great. While I was in there I went ahead and wired the second air conditioner to a second 20amp plug. Now I can run both air conditioners at the same time!  I separated the black and white wires and put them on switches. I'm very tickled all this worked out. I'm going to keep an eye on it and see how it goes.

[78elandan2]

I have a question for you guys. Why didn't the converter sense the 200vac coming in and kick a breaker or something? Also, why did my surge protector for the tv not kick off either?

[DaveVA78Chieftain]

Converter does not have any type of circuit to monitor input voltage.  It is simply a basic full wave rectifier circuit.
Surge protector?  I suspect it depends on it's design.

Dave

[ClydesdaleKevin]

Decided to tack this question on here.  Genny is still putting out 140+ volts, with the idle as low as it will go and still run.

Its an Emerald III, 6.5 gasoline, circa 1989.

At this point, would I now want to adjust the governor linkage or something?  I haven't needed the genny for a while so haven't bothered fixing this yet, but would love to run the genny while traveling this summer to run the rooftop AC while driving, and am afraid the high voltage might damage our relatively new Coleman AC.

Oh yeah, spec/model number is 6.5NHEFA26100E.

Thanks!

Kev

[DaveVA78Chieftain]

Governor speed adjustment is based on frequency (62-63Hz).  Procedure is in the service manual (965-0528), pdf page 70 [manual page 6-16], available in the free manuals section.

Voltage is primarily controlled by the Voltage Regulator (VR1) not generator speed.  Spec E unit Wiring diagram [points based unit] is shown on pdf page 106 [manual page 8-4].

Troubleshooting high voltage problems is addressed on pdf page 110 [manual page 8-8].  That states: It lists 6 possible problems with number 4 being - if frequency is within limits [62-63] and voltage is incorrect [>132VAC with no-load or <112VAC under full load] then VR1 is defective.

You need to read this section of the manual before doing anything.

Dave

[ClydesdaleKevin]

Thanks Dave.  I'll check it out today.  I actually have the original hardcopies of the manuals.  Hope its just an adjustment.  We are out in the boonies, no Onan dealers for miles...lol!

Kev

[ClydesdaleKevin]

My bad guys.  Patti informed me that I already fixed this problem, and I didn't believe her.  A lot on my mind and all.

Fired up the genny and let it run for 30 minutes.  Ran fine and strong.  Voltage was 124.

Guess she was right. 

Kev