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lonfu · 01-27-2020, 09:13 PM

01 Newmar 3852 DSDP on a FL chassis with a cat 3126b..... My old todd engineering transfer switch was starting to sing pretty good in its plastic box. did not notice any heat on the wires or relays but it would sing me to sleep at night because it is located just below my pillow in an outside compartment. So... decided to replace it with a brandy new Progressive Dynamics PD52DCSD transfer switch. Got the switch, installed it exactly like the old Todd unit. Took pix, same wire, no burned ends but noticed that the wires were trimmed a bit short and so the lug screws were hitting the insulation on a couple of wires. The relays were not warm to the touch. experienced electrical old fart...wired a few houses garages and such so I know how to tighten down the lug screws correctly.

But.... noticed that the shore power relay was warm and had heated up the coach lead in wires. The top right wires and rigth side relay. They were warm to the touch as was the relay....

Is this normal for this model?

I pulled the cover off and the relay and wires seems to be cooling off after a couple of hours. No big loads, frig and TV certainly not 25 amps per leg. Shore power wires are not warm, neither were the gen set wires when I tested the unit.. anyone have an idea what is going on with this relay???? I did a search of this site as well as others but can't seem to spot any posts about warm relays.

homerbw · 01-28-2020, 07:03 AM

I would call Progressive Dynamics and ask them about this.

lonfu · 01-31-2020, 07:13 AM

Quote:

Originally Posted by homerbw

I would call Progressive Dynamics and ask them about this.

I did call them and they are sending me out a replacement unit. Strange that a relay overheat and smell like burning rubber.

lonfu · 02-06-2020, 07:03 AM

Installed 2nd progressive PD52 unit. switch and wires heated up with in an hour. Not sure what is going on. Wires are clean and shiney. only shore power side of switch wires are hot. I suspect that the switch is again faulty. Checked temp and it is 35 degrees over ambient. Shore power wires once past the box enclosure cool off and no temp issues, only right at the switch. The plug head, and where it connects to the switch is cool and the gen set wires are cool too when running. very strange.

lonfu · 02-07-2020, 06:57 PM

Called Progressive again, tech suggested that it is the DC coils that are getting warm not the switch contacts. So, fired up the gen set and the gen set relay got warm and the wires at the shore power relay cooled off. Looks like the shore relay coil is running at 120 degrees. The wires are not what is hot, but rather the actual coil in the relay. Fired up bot ac's and the frig, they drew 27.5 amps but the wire temp did not go up so must be the relay coil itself. I drilled some ventalation holes in the cover to allow air to raise to the top through one of the box holes to help with cooling the coil. Tech said that drilling the holes would void the warranty, but it is only a one year warranty so figure more cooling will make it last longer...

Buckeye75nc · 02-10-2025, 11:26 AM

lonfu, which Todd Automatic Transfer Switch did you replace. I have a Todd model PS-260S to replace, similiar to yours, that has a couple burnt wires and trying to find a replacement ATS. Thanks. John

lonfu · 02-11-2025, 09:14 AM

Quote:

Originally Posted by Buckeye75nc

lonfu, which Todd Automatic Transfer Switch did you replace. I have a Todd model PS-260S to replace, similiar to yours, that has a couple burnt wires and trying to find a replacement ATS. Thanks. John

I can't find a pix of the original transfer switch or the model number. I do know that I decided to upgrade to a unit with a included surge protector and found that the prices for these things were all over the place. I found that most of the diff brands have the same transfer switch but the outside cover changes. I paid about $270 incl ship tax from amazon with the surge protector. I also ended up replacing the coach 50 amp shore power plug with a screw down lug unit. I've had no problems since I replaced with the transfer switch. still gets slightly warm when plugged in but no hum. If your wires are burned, I'd look at your shore power plug, when under heavy load is it warm? they use a crimped connection and after a few years that crimp fails. Also, never hurts to check your screw down electrical connections. If you look at the above pix you can see how little was under the screw down lug which can cause over heating lug problems.

twinboat · 02-11-2025, 10:33 AM

2 things,

1, it's capable of 50 amps per leg, not 25 amps. 120/240 50 amp service supplies 50 amps per leg.

2, The inclosure is fire rated. Drilling holes in it just killed the rating.

Psneeld · 02-11-2025, 10:43 AM

Relays that require power to hold position (either open or shut or just one way or the other) can get warm.

I know 12V propane solenoids when active get very hot, too hot to touch. Pretty scary thinking they are the safety feature in propane plumbing.