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RedWing Nut · 06-25-2013, 09:19 PM

I sold a 1989 HR Imperial last summer. It is 30 amp with a Magnum ME2012 invertor. The current owner sent me this e-mail today. I replied that I thought it was the transfer switch.

Any thoughts?

Quote:

In a nutshell, we are not getting power from the shore when plugged in.
Here is the backstory and information I have so far:
Yesterday (6-24-13) while plugged into shore power the 120v system abruptly stopped working. Laurie was running a hair dryer in the bathroom, and I was running the microwave. Two room fans were on. No AC units were on. I checked the 120v breakers, but none were tripped.
Next, I checked the GFIs both in bathroom, and on shore. None had been tripped.
All 12V systems worked fine in all respects.
All of the 120v system works fine (including AC units) when on the batteries/inverter. So I figure that your super handy-dandy Magnum Energy system is working fine.
NONE of the 120v system works when plugged into Shore Power. I have checked all the way from the outside (shore) plug to the automatic power switch (box behind the breaker box) and it reads at 120v all the way. There is no voltage reading at the 120v breaker box when shore power is plugged in.
The generator runs fine, and produces 120v at the breakers that are located on the generator, however, since last October or November, I have not been able to charge batteries or run the 120v system directly by running the generator. It appears that the juice is not making it to the automatic power switch(????). I have not pursued this issue as diligently since we have not done much boondocking yet. It may be possible that the 120v is making it to the auto power switch, but I don’t recall measuring voltage at the auto power switch in the past.
My primary objective right now is to get shore power to run the 120v system until vacation with the kids is over. Any ideas that you have that could lead to an attempted diagnosis (or quick fix), or to other available resources would be very much appreciated.
Thanks so much for all of the wonderful attention you paid to the motorhome when you had it, and thanks in advance for any ideas or suggestions you may have on this issue as well.

Moonrover · 06-25-2013, 09:45 PM

Your purchaser is using the term "automatic power" switch. I presume that is the transfer switch. Tell him to check for lug tightness on all of the in and out connections. Then check (with power on) for voltage on the connections. When he said he checked all breakers in the rig, I must assume he cycled them off then back on. Position of breaker handles after tripping may still look "on".

mgscott4 · 06-26-2013, 03:22 AM

I agree with Moonrover, it sounds like the transfer switch is bad, or bad connection. They are easy to troubleshoot with live voltage (be careful). The wiring diagram is usually under the cover. The transfer switch is nothing more than a relay that passes the power through from one source or the other.

There could be a surge protector inline with the power cord too. The surge protector could be the problem. If there is one, bypass it.

hogdriver · 06-26-2013, 06:16 AM

That sounds like a failed transfer switch. They fail all the time, especially if the owner is Transfering power with heavy loads on it. They (relays)are wear items.

RedWing Nut · 06-26-2013, 12:13 PM

I got another e-mail from the owner. It reads as follows:

Quote:

Hello Steven,
First, thank you so much for your help.
Based on your email yesterday, I felt more confident of my guess that the transfer switch may be the culprit. The link you sent with the typical electrical diagrams helped me a great deal.
I looked and tinkered some more yesterday and slept on it last night.
This morning I felt comfortable enough that I bypassed the transfer switch by disconnecting any wires running to the Magnum (just to be on the cautious side). I then ran a line directly from the shore to the breaker box in the hallway. That way I am sure that there is nothing between the shore and the 120v system.
The 120v system works great now from the shore, and the 12v system works as well. After reading the feedback you sent me from the forums, I feel much more comfortable that the problem is with the transfer switch.
Now we can relax and enjoy the remainder of our vacation with the boys without the worry of possibly having to leave the MH in a repair shop for days. If we can have it serviced under reasonable conditions and price during vacation, great. If not, we can survive just fine until after vacation.