110 volt system won't switch on.

I hope someone can answer this for me.  I'm confused about the electrical system in the coach area of my 1995 damon intruder.  I'm not getting 110 service to any of my electrical outlets, the microwave, or the refrigerator.  Sometimes, it will come on for a few minutes, but soon shuts off and won't come back on.  This happens when I run the generator and when I plug it into the house or campground service.

I replaced the converter, but it was doing this before I replaced it as well.  I wanted to replace the converter anyway and I was hoping that it would fix the 110 problem as well, but no luck.

I put a voltmeter on the wires going to the main breaker and to each of the other individual breakers.  They all register 110 volts.  However, I am only getting 12 volts to the fridge and micro.  My first thought was that it might be a bad breaker, but I discounted that, because of the 110 volts registering on each of the.  The micro is on a separate breaker.  There must be something "after" the breakers that is keeping the power from getting to the outlets and appliances.

I know there's a switch that automatically changes over from the generator to the shore electrical, but with 110 volts registering, it makes me think that it's not the switch.  However, when I plug in shore power, I hear a sort of "thump" noise.  After a few minutes, the microwave starts blinking, but doesn't work.  The fridge automatically switches over to LP when I turn it on and all of the outlets in the coach are dead. 

I hope someone can give me a lead where to look next!

Thank you!

Your explanation is quite confusing to me.

1. There is or should be NO 12v feed to the microwave. It is only 110v

2. The Micro starts blinking but does not work. If it is getting power (blinking) it should work unless it has givin up the ghost.

So on to your issue. The first thing I would do is remove the breaker panel cover (with power disconnected) and tighten the main power feed lugs. Then locate the transfer switch and do the same. It really sounds like a loose connection that loses contact as it gets hot.

There is a good chance that this will fix your issues discounting other things like a GFCI that is tripped.

The only time I have seen this happen that it was not the above was on an oddly installed Inverter. ( if inverter was on Half the house was dead.)

You motor home has 3 different electrical systems

1: The Truck part, this is all the stuff you would expect to see if it was a truck built on the same chassis.. I won't discuss it farther since it's not the problem.

2: House 120 volt
3: House 12 volt

These do have a part or two in common and some devices in the HOUSE part use both.

The Microwave is a pure 120volt device, it uses 120 and only 120  UNLESS. (See INVERTER)

Outlets, Likewise

Television, Radio and their support electronics are most all 120 volt, EXCEPTION is the TV antenna, which is a 12 volt device and possibly one relay which is a truck part.

The converter (Or if you have an inverter/charger it) converts 120 volt to 12 volt. to run lights, water pump, Furnace, Fans and control power for several things that need it.

If it is an inverter/converter it also inverts 12 volt to 120 volt for Televisions, and possibly selected outlets and the microwave (Depending on the inverter size)

Refrigerators, Water heaters and some Air Conditioners, though they run on 120 volt, also use 12 volt for control.. IF the batteries are dead and/or the converter is defective they may fail to operate.

Power comes in from the park via (in most cases) an inlet on the side or rear of the RV,  I have seen a loose screw on this inlet (mine) and all six screws inside the cord's outlet end on another RVers (Brand new delux 5er sticker still in window first time out)

Or it comes from the generator, On my generator there are two circuit breakers, but these are not like the ones you likely have in your stick house.

The ones in the stick house have three positions.. /=On, -- = Tripped, \=off

The ones on my ONAN have only two positions, ON and Off/tripped.

AND, if I'm parked facing north and it's like 4:30 in the efternoon, I can see the indicators on the dang things that say OFF when they are tripped.. Else the indicator is shadowed and I can't see it for (Term delted)..

I added a peal and stick label to the off side makes it easier to figure out.

From the inlet, or the generator power goes to an Automatic Transfer Switch.. On my rig it is located in.. The most logical spot (Sound me me fainting and hitting the floor).

There were no loose screws there but..... It was replaced under warranty and the replacement tech is the one who tightened them all down.

From there to the main breaker box. About half the screws there were loose, One took over two turns before it even started to snug down.  (Check while unplugged, and check all the screws, Breakers and bus).

And so it goes.  ON my coach the 120 volt issues were covered in the above.

Additional testing. Using a volt meter or test lamp check for voltage at the shore power leads (Be sure to read the labels) on the transfer switch,  The Generator and the output.

When my switch failed I had 120 volt on the Generator terminals, zero on the output.

A loose 120v wire (or wires) seems like the most likely explanation for this odd problem, but it could also be a poor wire connection (corroded or burned). The fact that the microwave blinks says it is getting at least some power, but it is unhappy with the quality of it.

Since the problem is the same on shore or generator, I would inspect and tighten the connections at the output side of the transfer switch (the thing that goes "thump") and in the load center (breaker box).

The only thing that is designed to disrupt power downstream from the breakers is a GFCI on an outlet circuit. A GFCI detects a short to ground and shuts off. It is quite likely you have a GFCI in the circuit that feeds the  wall outlets and possibly the fridge, but the dedicated microwave circuit is not usually equipped with one.

The display on my microwave blinks until I set the time on it's built-in clock.

My microwave flashes until I set the time.

I believe the 1995 Damon has an EMS or equivalent that the 120vac connects to. 

The EMS is a Load Control device that will shed 120vac circuits if the power demand is to high.  Normally the 120vac receptacles are not fed thru the EMS only the high amp circuits, i.e., Air Conditioners, Water Heaters, Microwave, etc. are controlled by the EMS.

While the Frig and wall outlets are not generally fed thru the EMS it might pay you to look at look at the EMS, I remember somewhere on this Forum about a Reset procedure. for the EMS and, if I recall correctly, there is a fuse associated with/inside the EMS. 
 

My 95 Challenger don't have an EMS, but it is a cheaper coach. My transfer switch makes  a noise when it switches, but that is when I'm using the generator. My coach also had loose wires in the breaker panel, and my micro numbers flash every time it looses power and comes back on until I hit the reset button. If you have power at the breaker but no power at the plug ins it has to be a GFI tripped, or someone may have installed an inverter and it is turned off or is bad. If the transfer switch makes a clunk when you plug in to shore power I believe it is wired wrong. The delay is so the generator can warm up a bit it powers the coach.

Thanks to everyone for all of the great leads!  I found the problem and now have to fix it.  When I got home this evening, I figured what the heck, I'll plut in the RV and see what happens.  Everything started working, but I wasn't comfortable that it would remain stable, so I started checking wires.  One of the white leads was a little loose, but I didn't think it was loose enough to cause the problem, so I pulled out the breaker box to check the wires in the transfer switch. 

As it turns out, the neutral wire connected to the ATS was hanging on by just one of the remaining windings left on the wire.  The first two inches where the wire attaches to the ATS was burned so bad that at first glance,  I thought it was the black wire.  The connector itself is corroded and doesn't look at all good, so I'm going to replace the ATS.

If I didn't have this blog to refer to, I never would have thought to find the ATS to check the wires.  The way my wife said it is, "It's a good think other people own money pits too!"  lol

Now, the problem is finding a replacement.  I currently have a Magnetek Model ATS 100 (rated 240 VAC, 50A, Tungsten, 50A ballast, Type 1).  I don't think they make this model any longer, but I did find a Parallax ATS 501 that claims to replace the ATS 100.  Do any of you have insight as to whether or not this is a viable replacement?  They cost about $181.00 and it claims that if it is plugged into shore and the generator is turned on, it will switch over without the need to remove shore power. 

I appreciate any advice you have on this model or any other model that might be a better fit.

Thanks again to everyone for your help!

The ATS 501 is the critter you need. Glad we could help.

Happy Camping!

Note: available on Amazon.com for $162.47 plus shipping unless you are a Prime member.
http://www.amazon.com/Parallax-Power-Supply-ATS501-Transfer/dp/B002SSEXSC/ref=sr_1_1?ie=UTF8&qid=1383224895&sr=8-1&keywords=ats-501

I used one of these in a fixed application and it should work fine for your RV.  It's just a 30 amp industrial relay in a box with a time delay circuit board to allow the generator 30 seconds or so to come up to speed before switching to it.  And is significantly less expensive:

http://www.amazon.com/POWERMAX-PMTS-30-AUTOMATIC-TRANSFER-SWITCH/dp/B006FLT0IG/ref=sr_sp-btf_title_1_11?ie=UTF8&qid=1383244541&sr=8-11-spell&keywords=rv+transferswitch

I did find a Parallax ATS 501 that claims to replace the ATS 100.  Do any of you have insight as to whether or not this is a viable replacement?  They cost about $181.00 and it claims that if it is plugged into shore and the generator is turned on, it will switch over without the need to remove shore power. 

Click to expand...

Hot switching is not a good idea, even if the switch will physically make the transfer.  You'll send heavy currents through the switch contacts.  And there's nothing to ensure that shore power and the generator are in sync with each other when the transfer occurs.  If one source is going positive while the other is going negative you'll send a hefty spike into the downstream loads.

LOL, Lou.  I'm glad you got that last edit in there before I did a lot of typing to point out that it was switching under load that would be the problem.....

Yeah, it's why I decided not to pursue a career in Journalism.  For some reason, I don't see mistakes or omissions in my writing until I re-read them after they appear in print.  And no, using the Preview button doesn't help.

contactor should be break before make..no chance of opposite phase spikes. unless you are going to turn off all loads before switching, you you are going to switch under load. the contactor is designed for this. Only high dollar synchronous switching systems provide autoparalling no break switching.
Bob

If one source is going positive while the other is going negative you'll send a hefty spike into the downstream loads.

Click to expand...

The transfer is just plain too slow for this to be a meaningful consideration. The current cycles 60 times/second, while the transfer relay moves in more like one second.