AC Electrical Feed Problem -- Only partial AC power available

[Birddog Pilot]

Here's a strange one for all you electrical experts out there. We're in the final stage of a two month trip and the Alpine has been operating perfectly with absolutely no problems -- until yesterday. We are presently visiting friends and are connected to their 30 amp shore power. That's the good news. The problem is that we're only getting power to either of the air conditioning units and the refrigerator, nothing else. The inverter is not receiving power and neither are any of the AC wall outlets, overhead kitchen AC light, the TV and other audio/visial equipment. When I pull the plug to the shore power and run the generator, ALL the AC powered equipment; air conditioners, lights, inverter -- everything AC works. I went through a shut down and reset of the main switches, checked all the AC breakers and stuff like that; but still only partial AC power. Oh yes, the Vansco panel looks reasonably healthy with lights 3, 4, and 19 illuminated. What I should have done is to have taken a picture of the Vansco panel with all the "normal" lights illuminated to compare with what I've got now -- next time.

Dick Bunting
2006 36' FDTS

[dgerstel]

Dick,

The Vansco system has nothing to do with the shore power. What type of adapter for 30 amp to 50 amp are you using? Have you checked the polarity of the 30 amp outlet?

[bobkathfl]

Hi Dick!
We had the same problem with a "98 Tradewinds. It turned out to be a relay in the auto transfer box that switches automatically from shore power to gen. I taped the relay and it released end of problem. Look into it with all power off for safety.
Bob

Quote:

Originally Posted by Birddog Pilot Here's a strange one for all you electrical experts out there. We're in the final stage of a two month trip and the Alpine has been operating perfectly with absolutely no problems -- until yesterday. We are presently visiting friends and are connected to their 30 amp shore power. That's the good news. The problem is that we're only getting power to either of the air conditioning units and the refrigerator, nothing else. The inverter is not receiving power and neither are any of the AC wall outlets, overhead kitchen AC light, the TV and other audio/visial equipment. When I pull the plug to the shore power and run the generator, ALL the AC powered equipment; air conditioners, lights, inverter -- everything AC works. I went through a shut down and reset of the main switches, checked all the AC breakers and stuff like that; but still only partial AC power. Oh yes, the Vansco panel looks reasonably healthy with lights 3, 4, and 19 illuminated. What I should have done is to have taken a picture of the Vansco panel with all the "normal" lights illuminated to compare with what I've got now -- next time. Dick Bunting 2006 36' FDTS

[Birddog Pilot]

Hi Dale,
No, I haven't checked the polarity of the 30 amp. But wouldn't you think the Surge Guard unit would check for the polarity, over/under voltage and things like that before it would allow the incoming power to be activated? Like I mentioned, the air conditioning unit/s and the refrigerator are working with no problem; it's just all the other ac items plus the inverter that are not getting power. The adapter, 50 to 30, is one of the heavy duty types with a short length of 50 amp cable joinging the respective connections.

Dick Bunting
2006 Alpine 36' FDTS

[Birddog Pilot]

Hello Bob,
It will be worth a try. Sometimes the ol' "tap and wack" method will work small wonders.

Dick
2007 Alpine 36' FDTS

[Dave Fernandez]

Hello Dick:

Check and make sure the 30 amp receptacle is 30 amps 120 volts on one leg, the second leg is ground. If it were wired incorrectly at 240 volts, 120 volts on each leg for a Residential Clothes Dryer it could have damaged your surge protector. ( That’s what it is for) They use the same plug 30 amp 120 volt RV receptacle and a 240 volt Residential Clothes Dryer.

[EngineerMike]

Dick- If you have a residential fridge, disregard the following:
Sounds like your inverter transfer switch is kaput. There is an xfer switch inside the Xantrex, as well as the SurgeGuard xfer switch. The Xantrex switch controls only the stuff that gets 120 direct from the Xantrex or gets 120 inverted from the Xantrex. I think

[dgerstel]

Dick,

If the transfer switch were bad, you would have no power to the Air Conditioners. I am suspicious of power in, as the inverter (and its transfer switch) works on the generator, but not the shore power. A 30 amp 120 volt receptacle has 120 v on one slot, has neutral (same as ground) and the round hole is the ground.



Test from ground to right slot, should be no power.
Test from ground to left slot, should be 115 to 120 volts.
Test from slot to slot, should be 115 to 120 volts.

[EngineerMike]

The SurgeGuard, per its lit, should: not close or will open (contactor) in the event of an open line, open neutral, open ground conductor, or reverse polarity condition. So 240V would leave it short a ground or neutral, and probably be read as reversed polarity w/120V on the leg SG thinks is neutral. Nothing should have 120 if that's the case & SG is working.

Looking at a 2006 34feeter 120V schematic (which should be same as Dick's coach unless he's residentially refrigerating), power comes into SG, then Main Panel, then out to Inverter (& its xfer switch), then to 30A Inverter panel. My assumption is that the Xantrex xfer switch switches only the 30A inverter panel, and power to other stuff outa the Main Panel will be OK even when the inverter xfer has an issue. The coach has 4 outlets not on inverter- PS "cab" outlet, fridge (unless its res-fridge), washer/dryer, & dishwasher which would have 120V under my conclusion. One AC would run & not the other if this analysis is correct & the 120V supply is correctly wired.

However, in order to have everything work w/the gen, the Xantrex xfer had to be working just then. That would make it an intermittent failure. Clear as mudd

[dgerstel]

I guess I should have added, I have found times when the inverter, SurgeGuard, etc have not worked as one would expect. I helped test an electrical problem, over the phone, where a SurgeGuard would not power up from a 30 amp shore power source. The voltage, polarity, etc was all normal, yet it would not work. When the coach was moved to another site, everything worked fine.

[Rick J Fisher]

If you have not solved your problem yet, check this. One leg of your two leg 50 amp hookup is dead when plugged into a 30 amp converter. Some 30 amp converters only activate one leg. Usually the one most everything but one A/C is on. Check for 120 volts between each of the parallel slots and the u-shaped ground hole. If one is dead (while using a 30 amp adapter), replace the adapter with one with the yellow handled plugs. If you have power to both legs at the adapter, check the Surgegaurd transfer switch. It has three relays (contactors) that switch from the generator to the shore line when shore power is detected. Mine failed so that the relay activated but not enough to connect the leg. I removed the unit (very difficult) and sent it back to Surgegaurd. They replaced the relay and it is fine. Anybody who has to remove a Surgegaurd, contact me for some tips.

[wa8yxm]

Three possible answers, one not likely

First: I do not think it's an EMS failure, I think the EMS (if you have one, Enegery Management System) is working properly... Why, do you ask, do I say this? "We have power to EITHER of the air conditioners, not both, but either, that is what an EMS does.

Suspect 1 is the 30/50 adapter

Suspect #2 is a screw loose... Inside the breaker box. NOTE Many RVers have a few screws loose.. of that type... NOTE #2, UNPLUG before you tighten.

[Birddog Pilot]

A big thank you is due to each of you; Dale, Bob, Dave, Mike, Rick, and wa8yxm for your outstanding efforts and ideas in troubleshooting this electrical problem. I apologize that I have not gotten back to you sooner, but we did not have full time e-mail capability until we got home a couple days ago. Mike, Dale, and even Lindsay Hargett should receive the accolades in the sleuthing department for coming up with the Surge Guard and its transfer relays for being the probable culprit for this electrical anomaly. Also, Bob suggested the tried and true, rapping and/or tapping, method that often works for some of the more unusual problems. Apparently after applying this often persuasive technique in conjunction with a re-torque of the connections in the box (this is the second Surge Guard unit by the way) full AC power was restored to all outlets and appliances. Often as I read this wonderful forum I am amazed how many times most of our electrical problems can be resolved by just tightening or cleaning connections. One would think after almost thirty years of owing motor homes I’d remember this one simple troubleshooting method. Oh well, next time… By the way, I do have a spare Surge Guard that will now be in my spare parts bin, just in case.

Our two month 4000 mile trip was a blast; the Alpine was, as always, a true pleasure to drive; and for the most part the electrical glitch was the most serious item we had to deal with. Well, almost… We had the coach in the driveway for unpacking and cleaning when I discovered a puddle of coolant under the radiator. Yup, add another aluminum radiator failure to the long list. I’m in the process of getting together with R.V. Specialists here in San Diego, same place as our SDCYCLIST, aka Milo, had his done. He had such glowing reports of the service at this facility and is so impressed with the replacement unit from Mac’s Radiator, Portland, OR; that this seemed to be the logical choice for the work. I was also encouraged with his coolant temperature numbers because I’ve never been particularly impressed with my 190-197 degree readings on straight and level roads with outside air temps in the 70’s to 90’s. But, that’s another issue that needn’t be added to this electrical problem topic.

Once again, thanks to all for your kind support, you really nailed this problem.

[EngineerMike]

Based on this thread, I decided I needed a spare contactor in my collection of trash. Stuff like that will never be available in Mexico, and the SG's integral xfer switch contactor is square in the way of coach power if it goes bad- no electricity from shore or gen.
Happened to be getting specs in an electrical supply joint (basically like a big toy store ) on an 800A 3 phase service panel setup for a client, so I asked about the contactor number which is easily visible taking the face plate off the SG. No sweat- a mere $650 with maybe a little off for a good guy price (actual list ~$740). WOO HOO!!!
The whole SG can be had for less. So now I'm thinking double tapping a 50A female outlet off the output lugs and nippling the new outlet box to the output side of the SG or screw it to the ceiling of utility bay. That way I have an option to bypass SG altogether in a pinch using my 30A shore cord & 50A adapter; probably run $50 in parts.

While I was in the SG I checked terminations. Sure enough, there were 4 of 6 incoming wires w/insulation pinched in the terminal from too-short stripping, so I clipped the offending cables & did a clean strip & termination. If only marriage was this easy