AC power problem

Forum for both AC and DC electrical components. From engine alternator to dashboard, inverter to batteries, and everything electrical in-between.
ProCycle
Posts: 135
Joined: Sat Oct 03, 2020 1:28 pm

AC power problem

Post by ProCycle »

I need a little help troubleshooting an AC power issue. 😒
My 97 Ivory is plugged in to shore power but I do not have any AC power to any circuits. When I plug in or unplug the shore power cable I can hear the transfer switch making it's normal clunk. I also have no AC power running on the generator. The house batteries are fully charged. If I turn on the Magnum inverter then I DO get AC in all the circuits that run off the inverter. Also the remote control inside the coach shows an "inverter fault" warning but I don't have any information what that might be trying to tell me. I did have an inverter problem in September when it was not charging the batteries but doing a reset seemed to have solved that.
Last edited by ProCycle on Sun Dec 05, 2021 9:30 pm, edited 1 time in total.
Jeff
1997 Ivory Edition 3740 Cat 3126 Allison
Safaritoonces
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Location: Bowen Island, BC
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Re: AC power problem

Post by Safaritoonces »

You may have a broken wire or pitted contact in the transfer switch. Remove the plate use a DVM to read the shore input, 120v on each leg to common, zero volts between legs. Then check the output side, it's a Y, 1 side shore in, 2nd side generator in, one out to inverter. If on shore power you should have 120v out. The relay board is replaceable if damaged.
Robert and Bev Lewis
2000 Safari Continental, since 2017
3126B Cat, 330hp
MD3060 Allison
Bowen Island, BC

https://safaritoonces.org/
ProCycle
Posts: 135
Joined: Sat Oct 03, 2020 1:28 pm

Re: AC power problem

Post by ProCycle »

Thanks Robert. I have power on the switched side of the transfer switch and at the coach's breaker box. Even at every breaker.

I've been studying the wiring diagram and see that when the inverter is off power has to pass through the inverter to two circuits. It either isn't getting to the inverter (which would explain my intermittent battery charging problem) or it isn't getting through the inverter to the outputs. This Magnum 2812 inverter does not have breakers for those circuits. Power does get to those circuits when the inverter is on which tells me the wiring connections for those circuits is fine. I'll dig into it deeper tomorrow. I still don't have shore power to the fridge or dining outlet (even though I read voltage at that breaker) so something else is wrong there.
Jeff
1997 Ivory Edition 3740 Cat 3126 Allison
05wingrider
Posts: 104
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Location: Spokane, Washington

Re: AC power problem

Post by 05wingrider »

This is a long shot, but have you checked for a hidden GFCI outlet on the section that has no power? I had issues with my '96 and while searching found a "hidden" GFCI outlet under/inside the cabinet beside my entry door that was tripped. I wouldn't have found it other than I had pulled the drawer out for some reason and just happened to look and see it in the top and that there were wires coming out of it (and in my case it restored the power that I was having issues with)
Duane
96 Sahara 30', 250hp Cat 3126
Allison 6spd MD-3060
2015 Jeep Cherokee Trailhawk "Toad"
Spokane WA
wolfe10
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Re: AC power problem

Post by wolfe10 »

If nothing 120 VAC works (not just outlets, but roof A/C, etc) with either generator or shore power, you have either a wiring issue between the ATS and main breaker box, or the main breaker is tripped.
Brett and Dianne Wolfe
Ex: 2003 Alpine 38'. Ex 1997 Safari Sahara. Ex 1993 Foretravel U240
Moderator, FMCA Forums 2009-2020
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ProCycle
Posts: 135
Joined: Sat Oct 03, 2020 1:28 pm

Re: AC power problem

Post by ProCycle »

wolfe10 wrote: Mon Dec 06, 2021 10:10 am If nothing 120 VAC works (not just outlets, but roof A/C, etc) with either generator or shore power, you have either a wiring issue between the ATS and main breaker box, or the main breaker is tripped.
I haven't checked for power at the A/C units yet. But I do have shore power at the breaker box - 247 volts between the red and black and 123 volts at each individual breaker. It appears that the real problem is in the main AC feed to the inverter which in turn feeds the 2 circuits coming off the inverter. Those circuits probably power everything that is dead. If I get a break in the rain I'll be checking into that today. I'm working off a wiring diagram for a Sahara which is different in many details from my Ivory. So there may be some outlets with shore power that I haven't checked yet. Possibly the ones under the bed.
Jeff
1997 Ivory Edition 3740 Cat 3126 Allison
alnleslie27RB
Posts: 5
Joined: Thu Jul 09, 2020 7:00 pm

Re: AC power problem

Post by alnleslie27RB »

It sounds like the inverter's pass-thru circuit may have failed. An internal relay connects/disconnects the pass through if you are inverting to isolate incoming 120v from the inverter output. I hope that helps. When I changed from an ME (modified sine) to an MS (Pure Sine) inverter I made plug-ins on the input and output so I could bypass the inverter in case of a pass-thru relay failure. My Magnums have been reliable, but just in case. :)

A final thought. Do you have a push button circuit breaker on the side of the inverter? Check it just in case. It shuts off all AC to the inverter.
Al & Leslie Richards
2006 Safari TREK
Workhorse 8.1 / Allison 6 Speed
ProCycle
Posts: 135
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Re: AC power problem

Post by ProCycle »

alnleslie27RB wrote: Mon Dec 06, 2021 1:04 pm It sounds like the inverter's pass-thru circuit may have failed. An internal relay connects/disconnects the pass through if you are inverting to isolate incoming 120v from the inverter output. I hope that helps. When I changed from an ME (modified sine) to an MS (Pure Sine) inverter I made plug-ins on the input and output so I could bypass the inverter in case of a pass-thru relay failure. My Magnums have been reliable, but just in case. :)

A final thought. Do you have a push button circuit breaker on the side of the inverter? Check it just in case. It shuts off all AC to the inverter.
There are no breakers on this particular inverter. It should have them bur whoever installed it 10 years ago did not do the install properly. There should have been an external box with 2 breakers.

I've determined that the inverter isn't getting any AC power. There is a junction box that I suspect has a poor connection in it. Just need the rain to stop so I can dig into it.
Jeff
1997 Ivory Edition 3740 Cat 3126 Allison
TDJohn
Posts: 552
Joined: Sun Oct 27, 2019 11:34 pm

Re: AC power problem

Post by TDJohn »

I think Duane is right on the money. Check all your GFCI outlets, since they are daisy chained, they will affect the lights and multiple outlets. On my coach, I have not figured out why (yet), but If I disconnect from shore power it will trip most if not all of my GFCI outlets, resulting in nothing working. If there is no output coming out of the inverter while on shore power, be sure to check the 30amp breaker at the inverter and at the breaker panel. Also check for loose ac input connections inside the inverter.
In any case, your refrigerator should not run off of the inverter, so if you have power at the refrigerator circuit breaker but on at the refrigerator outlet, then it is very likely that some or all of your GFCI outlets are tripped. Remember, you have to have shore power present at the breaker box/outlets to reset the GFCIs.
John
'95 Serengeti, Cummins C8.3-300
Allison 6spd.
ProCycle
Posts: 135
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Re: AC power problem

Post by ProCycle »

TDJohn wrote: Mon Dec 06, 2021 7:28 pm I think Duane is right on the money. Check all your GFCI outlets, since they are daisy chained, they will affect the lights and multiple outlets. On my coach, I have not figured out why (yet), but If I disconnect from shore power it will trip most if not all of my GFCI outlets, resulting in nothing working. If there is no output coming out of the inverter while on shore power, be sure to check the 30amp breaker at the inverter and at the breaker panel. Also check for loose ac input connections inside the inverter.
In any case, your refrigerator should not run off of the inverter, so if you have power at the refrigerator circuit breaker but on at the refrigerator outlet, then it is very likely that some or all of your GFCI outlets are tripped. Remember, you have to have shore power present at the breaker box/outlets to reset the GFCIs.
My inverter does not have a breaker anywhere on it.

I'm pretty sure the problem is a connection in a junction box between the breaker box and the inverter. It's been raining too hard for me to go out there and dig into it today. I'm hoping I will find a loose wire nut, tighten it up and be good to go.
The remaining mystery is there has been no shore power to the fridge or the dining area outlet that is connected to the same circuit. That is likely to be some other issue. I've pushed the reset buttons on all my GFCIs but with no power to them I can't test them or trip them. I may have a faulty GFCI in the basement under the fridge. I'll look into that after I get a chance to check out the connections that feed the inverter.
Jeff
1997 Ivory Edition 3740 Cat 3126 Allison
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