Community Forums

hogtails · 08-23-2016, 04:20 PM

i am posting for my sister who just lost her husband. They purchased a Travel Supreme about a year ago. He pretty much took care of everything. Recently she was running both a/c's on the generator when (as she said) both made an "exhaling" sound and shut off and the generator shut down. Now both units will run with the generator (apparently the above problem did no damage ) but the zone 1 (living space) will not run on shore power. Zone 2 (bedroom) runs on both. I am very mechanically inclined but am terrible with electrical and have ZERO experience with motor coaches . It is an '02 Travel Supreme Select DS02 with a 500 Cummins. Any help/suggestions would be greatly appreciated.

Ray

MtnTrek · 08-23-2016, 09:26 PM

I'd be inclined to checking the transfer switch gear. Sometimes you can get arching and issues with the terminals and or spring loaded contacts on that device.

Best of luck.

yackman · 08-23-2016, 09:51 PM

You might check the inverter to see if possibly a breaker has tripped.

rag_ftw · 08-23-2016, 10:10 PM

I would check all AC circuit breakers and then the transfer switch. It sounds like the leg that supplies Sys #1 is not closing on shore power. Take the cover off the transfer switch and check for proper voltage on all the connections. You can find a print for your transfer switch on the internet. Let us know which switch you have and possibly one of us will already have the print.

If you have to get a new transfer switch suggest you get a solid state switch. The new mechanical units are not made in the US and they have a tendency to hum loudly. Since this thing is probably located under the bed that is not a good thing!

Good luck and keep us posted.

justaroamer · 08-24-2016, 07:48 AM

What is the power source you refer to as shore power? 50 amp, 30 amp, 15 amp???
Could be the inverter control panel is set to a lower power than 50 amp, even though you may be connected to a 50 amp source. If connected to power source not supplying 50 amp 220v then the zone 1 AC may be on a different leg/buss in the main breaker box....

twinboat · 08-24-2016, 08:49 AM

If it's a 30 amp RV, you may not get both ACs running on shore power. There would be a selector switch for front or rear AC.

The generator will run both because it had a 30 and 20 amp output. They use the 20 amp output for the second AC.

Have her check the plug on the end of the power cord for an amp rating.

2 blades,1 pin = 30 amp

3 blades, 1 pin = 50 amp

justaroamer · 08-24-2016, 12:39 PM

Quote:

Originally Posted by twinboat

If it's a 30 amp RV, you may not get both ACs running on shore power. There would be a selector switch for front or rear AC.

The generator will run both because it had a 30 and 20 amp output. They use the 20 amp output for the second AC.

Have her check the plug on the end of the power cord for an amp rating.

2 blades,1 pin = 30 amp

3 blades, 1 pin = 50 amp

I believe on the coach in question, would not have a generator with "a 30 and 20 amp output" , but an 8kw generator that would be capable of 50 amps 220v. The coach would then have a 4 pin male plug on the supply cord (220v). The question is are they using an adaptor to connect with, which would only give 110v and only be powering one leg/buss on the coach main breaker box.

If they are connecting to "shore power" via a down size adapter (i.e. 50 amp 220v (4 pin) coach cord adapted down to 30 amp (110v) or even down to 15/20 amp then the problem would be as I stated previously.
Really need to know what their power source is and how the power is supplied to the coach. If they are connecting via full 50 amp connection,
then the supply breaker could have a bad leg in the breaker or the buss connection at the supply side pedestal side.

MtnTrek · 08-24-2016, 02:20 PM

These are all plausible scenarios in the event that the coach had been moved re-connected etc., etc.
OP reads as if there was a sudden loss of power or the generator dropped out with a "humph". There may heat pumps (with reversing valves) up there that make that distinctive sound. Perhaps we'll get an update from OP'r

Be well.

hogtails · 08-24-2016, 05:03 PM

Thank you all for your replies . I went to the coach today and found the transfer switch but as i said i am horrible with electrical. The coach is hooked up to 50 amp service with no adapters. Unfortunately my sister was not around so i could not get inside. I do know the control panel is set for 50 amp. There is a breaker box in the control cabinet with i believe 3 20 amp and 1 50 amp breakers. Are there other locations i need to find ?Ask me to tear down a chevy 350 and rebuild it and it would be done , but this motor home is like brain surgery to me i don't have a clue . Again ,thank you all

Old Scout · 08-24-2016, 05:18 PM

OK--lots of shots in the dark here but think rag-ftw is on target. Since both units run on genset but not on shore power, it basically means all upstream components are working. So need to target/focus on x-fer switch. Genset has priority on most x-fer switches so those contactors are normally closed. Fact that front unit doesn't work on SP suggests that when x-fer switch transfers to SP, one of the SP contactors [one of two separate 120volt legs] isn't closing. This can all be verified with a voltmeter at the x-fer switch but based on your concerns about "all things electrical," you probably aren't the guy to do it [smile].
PS--if so equipped, surge protector could an issue but since original shut down occurred while on genset, symptoms point back to x-fer switch!

rag_ftw · 08-24-2016, 09:55 PM

Can you identify a brand and model number of your transfer switch?

Once you have that you can get a print and the testing part is really pretty easy. You would be measuring AC voltage across a couple bolt heads inside the transfer switch.

If you are willing to work with us there is enough knowledge in this group to talk you through some basic troubleshooting.

MtnTrek · 08-24-2016, 11:11 PM

Here is a generic overview of a MH and a typical flow diagram.

Depending on layout you may find the T/S in or through a bulkhead wall adjoining or close to the main breaker panel. Follow the leads from either you can see. Some coaches they're under the bed.

In the T/S itself (grey box) is often a pair of mechanically interlocking contactors. one is N.O. the other is N.C.
With all the power off you can often work the contactors spring loaded plungers / interlock with a screw driver and check for binding etc.
Likewise the contacts are spring loaded metal slugs.
Check all the connection lug screws & contacts for alignment. Burnt wire?
Spray it with contact cleaner if available. Discoloring will require investigation.

The control board becomes more difficult to diagnose, not so serviceable.

hogtails · 09-01-2016, 04:11 PM

Thank you all again for your help. rag ftw was spot on. Although i was told by 2 different people ( my sister and quite competent brother - in -law ) that the circuit breakers were not tripped, low and behold i looked and, surprise, the breaker for the front a/c was tripped. I do remember being told many times KEEP IT SIMPLE STUPID. I am sure i will post again since the help is quite abundant here.

Mr_D · 09-01-2016, 04:34 PM

A 50 amp service is TWO 50 amp breakers for 12,000 watts so an 8KW gen will not supply the full 50 amps.
A correctly wired 30 amp adapter will supply power to both legs of a 50 amp plug but you will be limited to 30 amps (3,600 watts) total
30 amps = 120 X 30 = 3,600 watts
66.67 amps = 8,000 watts
50 amps = 50 X 2 X 120 or 12,000 watts.