Transfer switch not locking into Short Power mode reliably

[Mike Shumack]

My Surge Guard 40250 Transfer Switch is not switching to shore power properly. When I plug in my 20A shore power cord (home storage) the switch keeps engaging and disengaging over and over. It s cluck, clunk, clunk, etc. If I unplug and re-plug a couple of times it will eventually stay locked in. I have not seen this behavior while camping (on 50A shore power) yet - but I think it is a matter of time.

so I'm thinking I'm going to need to replace it before it fails completely while I'm away from home. It looks like I can still get the 40250 model (which has the RJ11 jack for connecting to the Aladdin).

before I buy anything I thought I'd ask here - in case I missed some other potential cause of this problem. I did pull the cover and check the tightness of each conductor. Everything is tight and looks normal inside.

[Steve Huber Co-Admin]

Mike,
Per the troubleshooting manual, the contacts will disengage for the following reasons;  High or Low voltage or incorrect ground. Have you checked the supply and cord from the shore outlet to verify correct voltage and ground?
Steve

[Dale Soule]

I recently had a similar problem.  Bottom line my house batteries were bad and I had a broken ground wire that only had a few wires left to connect power to.  So0metimes it would be a quick clunk,  maybe 5 min.  maybe 30 min.

[Scott Shearer]

Mike,

Can you please share where you’ve found the 40250 with the serial data interface?

Thanks, Scott

[Mike Shumack]

Mike,
Per the troubleshooting manual, the contacts will disengage for the following reasons;  High or Low voltage or incorrect ground. Have you checked the supply and cord from the shore outlet to verify correct voltage and ground?
Steve

I have not tested the shore power cable or voltage supplied to the transfer switch. I'm running a 10GA 100 ft extension cable from a receptacle in my garage to the coach. The cable looks fine, and if fairly new. I suppose I could remove the cover to the Transfer Switch and attach my volt meter to the incoming wires to see what the incoming voltage is.
Why would the TS "eventually connect" if the incoming voltage was low? I suppose it could be teetering on the brink of in-range and too low.

Scott, I spoke too soon. Initially when I Googled "SurgeGuard 40250" I saw plenty of links, but now it's looking like most of those were showing for the 40260 model or an "out of stock" 40250. Ebay has a used one. So it's not looking so good. There are probably a few remaining at the RV salvage sites too. But I'm not seeing any new stock now.

[Joel Ashley]

20 amp over 100+ feet can get funky, even with a 10 or 12 gauge… been there, dun that.  It wasn’t too big of a deal with our old ‘84 Pace Arrow where you didn’t see a problem until maybe something burned up, and most devices held up regardless, but it didn’t have a sophisticated, intentionally protective switch like these rigs.  Yes, before blaming the switch (for doing its job) I’d definitely check voltage at the switch vs at the outlet to see what the drop is.  The Aladdin may give the incoming number also.

Joel

[Stan Simpson]

Mike, I have the same surge protector as you, and I also have a 100 foot 12 gauge power cord plugged in to an outside outlet on the garage. I've never experienced the symptoms you describe.

[Mike Shumack]

I measured voltage at the extension cord - and I have 122VAC.
Then I measured at the contacts inside the transfer switch. When I plug in (and the Inverter Powers on) I see 114 to 116VAC on my meter.
The SurgeGuard manual says the acceptable operating voltage is 105 - 132 VAC, so I'm within that range.

Also when I first plug in, and the contactor is being pulled in and then popping out, repeatedly (the "clunk" sound) my Aladdin display just shows "No Shore Power" so it doesn't provide any diagnostic help. It only shows the 114VAC when the contactor stays In (engaged). Should it be displaying "Low Voltage" if that was the problem? I don't know what the Aladdin displays in this regard since I have never seen an error/fault message.

I thinking the "control contactor" may be going bad. It is a Cutler-Hammer C65FNF360. There should be an "A" at the end of the part number (I believe) which indicates a "110-120V coil" in the contactor according the spec sheet.

If this contactor is available, that may be worth replacing. I'm not 100% convinced that is the problem yet, but I am leaning that way.

[Steve Huber Co-Admin]

Mike,
Since the inputs are in the spec'ed range, I tend agree that the control contactor is failing.  I'd order the same part # since even on the new units I looked at the trailing A is not displayed.
Steve

[Mike Shumack]

It's not looking too good on getting just the control contactor. This contactor was probably not a high production item, so not readily available.

I did order a "used" SurgeGuard 40250RV. Supposedly it has been "tested". I'll continue to use the old one until it fails completely (or I can get parts to replace the contactor at a reasonable price). At least I have a backup plan with the "used" one coming.

I'll keep looking for the contactor. If I can get one for under $350 it is probably worth rebuilding my current 40250. But I'm not willing to pay the prices I've seen on those that are available.

[Scott Shearer]

Mike,
I have seen an error message on our Aladdin display a couple of times, ‘Open Neutral’ and ‘Input Low Freq’. The messages were in red and as I recall, only displayed during the delay phase.

If the ATS doesn’t see AC power, the display should read ‘NO AC POWER PRESENT’, if the ATS has disconnected because it thinks that there is an error condition, I believe the display will read ‘NO AC POWER SELECTED’.

I realize that the shore and generator contactors are separate, but will the ATS connect on generator power? I think that both power sources share some of the surge protection circuitry.
-Scott

[Mike Shumack]

Scott, the ATS works fine most of the time. The only issue I have seen is when I plug into my 20A Shore power (home storage). I have never seen a problem with the ATS when connecting to 50A campground power or running the Generator. So I don't know if this is just an  issue with my "home storage" connection, or an early sigh of something going wrong.

As I post above, the issue is that on the 20A plugin the contactor wont stay pulled in. I can watch the contactor pull in and drop out, pull in drop out, about a dozen times before it stays in. Maybe the contactor coil is going bad - possibly there is some electronic fault monitoring circuit that is going bad. Or maybe the problem is completely due to my 20A service (extension cord plugged into garage receptacle) and there is a real fault. However I did not have this issue when I first started plugging in at home three years ago. And it seems to be getting worse.

I'm in Florida and we have frequent power blackouts (usually for a couple of seconds or minutes) during the summer storms. I have not thought to go out and see how the ATS is recovering from these outages. Now that I think about it, I am concerned that if that contactor is repeatedly failing it could get worse and maybe start a fire. Next power outage I'll go out and see if it is acting up when power is restored - I suspect it would.

Thanks for posting.
I found a used transfer switch and will keep that as a backup in case mine fails completely or gets worse. It would have been nice if I could just replace the contactor, but the prices I have seen for the contactor are higher than buying a complete new transfer switch.

[Eric Maclean]

Mike
I suspect that what is happening is the contactor pulls in and your inverter starts to charge which takes a large inrush of current which in turn creates a volt drop large enough to cause the drop out.
You should be able to run on a 20 amp source but the size and length of the cord is critical to avoid too much volt drop.

Eric

[Mike Shumack]

I think you're right Eric.
The contactor dropout does seem to start with the Invertor fan coming on (Inverter powering up) - about 1 or 2 seconds after I plug in my 20A shore power. I'm not seeing the voltage drop below 114VAC at the contactor terminals when the contractor drops out - maybe the contactor "pull-in coil" is seeing less voltage or just getting weaker.

Maybe it will help if I lower the "Set Shore Power" setting from 20A (my current setting) to 15A. I don't know if this will reduce the inrush current or not. But I'm guessing the inrush current is going to be the same regardless of the Set Shore Power setting. But I'll give this a try.

The Xantrex manual says this Set Shore Power setting is to reduce the battery charger rate if the AC load and Battery charge load approach the Shore Power circuit breaker rating. So the normal setting is to match it to the circuit breaker size for the shore power (or generator).

BTW - it wont help to turn off the Inverter before I plug in, as the manual says the battery charger is still On (whenever AC voltage is present) regardless of the On/Off switch position.

[Steve Huber Co-Admin]

Mike,
Eric is probably correct. However, since this circuit setup worked for a number of years, if I read your write-up correctly, something has changed to cause the problem. Some things to consider; Why isn't the garage circuit breaker tripping? If the inverter is applying enough of a load to drop the voltage from 120+ to less than 105, it's drawing considerable amperage. Are all the connections tight from the garage CB to to the RV? Have you tried a extension cords?
Steve