No power from genset

[smlranger]

Update: I'm Bummed

Well I ordered a new transfer switch and installed it (dang my old body doesn't fit in those tight spaces so good these days). Started generator, flipped breaker on genset and same result. Generator contactors on new switch clatter off and on rapidly. I tried to take voltage readings on the input side of the generator contactor and it was all over the place. Never did get any steady reading.

Went inside coach and my Magnum Energy remote panel was displaying the red 'fault' LED with the message 'AC Overvoltage.'

So at this point I am thinking it is a problem with the generator. I believe the 10K genset actually powers an inverter which delivers pure sine wave 120V....something beyond my ability and desire to troubleshoot. I have an appointment at my local independent RV repair shop who is also an Onan certified shop.

Always seems to be something right before our winter trip. Last year at this time one of the hose clamps on the generator gave way leaking coolant.

[gsander1]

The Onan 10 KW and 12.5 KW are not inverter generators. They run at 1,800 RPM and generate true sine wave power.

[Soppy]

Try switching off all AC breakers and turn the charger off on the inverter. Then fire up the generator and see if you can get a reading. The output voltage of your generator is dropping off when it gets loaded . The transfer switch will energize with a voltage above 100 volts and drop out when the voltage is somewhere below 80 volts give or take. You could have a bad voltage regulator on the generator or a loose connection somewhere between the generator and the transfer switch.

[Piros1]

I just read through your posting, I have done a lot of electrical diagnosing in the field. Electric is electric regardless where it generates from. There a two ways to diagnose your problem from the source out or at the load end back, I prefer to start at the source (the generator) and work my way toward the load (in this case the transfer switch). Shut the main off on the inside of the coach, open the generator to expose access to the circuit breaker where the wires are attached. Turn the breakers off and fire up the generator and see if you have power at the generator, if you do you will know the generator if working. You may or may not have to disconnect the load (wires coming out of the breakers) from the generator depending on if there is any load on your source wires going to your main breaker in your coach. If you have power at the generator then you have to work your way down the line one component at a time. Lose connections are big culprits of this sort of issues I electrical systems. Obviously be cautious when doing this as you are working with non ground fault power and I am sure you don't want to blow the plaque out of your arteries. (get electrocuted) Being funny but do be cautious and mindful of what you are doing, if you don't feel good about it hire it done.

[Pa Miller]

Mine did the same thing when the transfer switch went out , worked on shore nothing on gen even though the gen was putting out ..

[smlranger]

I am going back to the coach tomorrow and check whatever connections at the generator I can get to without a lot of disassembly of the enclosure. I am hoping to find something obvious like a loose connection. There is an access plate that reveals the power connections going out. Unfortunately, the main 45 amp double pole breaker on the generator is not easy to access. If I don't find something obvious, I will defer to the Onan certified mechanics at the shop. Anything internal (voltage regulator, etc.) will have to be checked by them.

One interesting clue is the fact that my Silverleaf continues to display a steady 120 VAC when the genset is running. According to the folks at Silverleaf (they were very familiar with how their systems were used in Country Coaches), that confirms that the generator is producing power as designed. If true, that certainly does seem to suggest a loose connection somewhere.

[Piros1]

I would still check power out of the generator and then go back to where it goes next. If your Silverleaf is reading it correctly then most likely it would have to be somewhere in the wiring past where it picks up it’s reading. It is definitely tough when you cannot easily access everything you need to check. Motorhomes you have to love them! But after 8 RV’s, cab overs, bumper tow, fifth wheel, and two coaches they are all money pits that require a lot of attention and I feel your pain. I’m going through some of my own. Hydronic heating issues, leaking slides, smoke out of the electrical compartment, slide pump failure, broken hydraulic line on my slide just for starters. My last trip out to Montana my slide pump went out at the beginning of the trip and I had to rig an in-line pump to get my slides in. My attachment brackets for my largest slide were missing from the coach when I purchased it, it had the large screws but no brackets. CC couldn’t even provide them. Also that is when the diesel part of my heat system went out. It seems here in the St. Louis, MO area the RV dealerships don’t believe in customer service don’t seem to know much about the larger coaches. So I have had to pretty much do my own repairs. We decided to pass on our fall trip due to the coach issues but hope to be back in full service by the first of the year. Sucks having to work outside and not under roof all the time. Do I feel your pain and wish you all the best in getting your issues resolved. Be sure to post your findings. Good luck.

[smlranger]

Well dang. It was something simple after all . Wish I had checked this first. Based on the excellent suggestions here, I went back out and removed the access cover to the block where the outgoing cable attaches to the genset. The neutral wire was loose in its space. It looked like someone cross threaded the threaded lug and there was little to no pressure on the connector crimped on the wire. I re-positioned the lug and tightened it down on the connector. Everything now works fine.

I am going to see if I can order this terminal block and have it in reserve. The screw seems tight but I wonder if vibration played some role in it coming loose.

[dons2346]

Just back each lug screw out a bit and put some Loctite on it, Problem of loose screws solved.

[Piros1]

I would strongly suggest that you check the screws coming in and out of the block. Loosen each screw and check and clean each wire coming in and going out and make sure they clean and not corroded before you walk away from this. I would suggest you maybe put a dab of no corpse paste on each wire then retorque each set screw. Once this is completed if you want you could put a drop of blue Loctite at the edge of each screw. If you it this way you should not have any issues as long as your threads are good and with the blue Loctite it will be removable in the future without a lot problems. Good luck and glad you found it. Happy Thanksgiving ���� to all of you out there.

[Piros1]

Sorry I should proof read before posting. Spell check you have to love it. It was supposed to be “no corrode past” and I have no idea where the question marks came from.
Happy Thanksgiving to all!