Transfer switch problem

[Boat wrench]

Went to plug in my new to me coach today power runs fine on the gen but shore side contacter will not ingagechecked power in 115 on both sides so I figure bad contacter. Replaced contacter same problem I am trying to just run chargers and fridge am wondering if 20 amp wall plug does not have enough juice to lock in the contacter? Any other ideas I am about out of ideas. Green light is lit on transfer switch circut board on gen nothing when on shore cord HELP

[jacwjames]

Do you know if you have a surge protector, which may also have checks for polarity, neutral, and hertz.

I have a hard wired HW50C Progressive that does the checks and if anything is wrong it won't let power pass.

If you don't have a surge protector the transfer switch may be bad.

I plug into a 20 amp plug at home, it is plenty to keep the batteries charged and run refrigerator. If batteries are full I can even run AC to cool the coach down prior to departure.

[Boat wrench]

A surge protector is on the list before the first trip guess the circut board may have taken a dump

[J. Frank]

I think most transfer swithes are hard wired for shore power and only switch when the generator powers up. When mine went out it worked fine on shore power but would not switch to the generator. Not an expert - mine could be different? The 20 amp plug is fine as long as you don't overload it. If you have an EMS with polarity checking, it could be your problem, as mentioned above. House wiring is not always wired correctly.

[SuperGewl]

Originally Posted by J. Frank

I think most transfer swithes are hard wired for shore power and only switch when the generator powers up. When mine went out it worked fine on shore power but would not switch to the generator. Not an expert - mine could be different? The 20 amp plug is fine as long as you don't overload it. If you have an EMS with polarity checking, it could be your problem, as mentioned above. House wiring is not always wired correctly.

Actually you have it backwards, most are hardwired for generator because it should always be wired correctly from the manufacture and you have no idea what type of shore power you are going to get. If you start the generator when on shore power they default to the generator.

[twinboat]

Generator power is priority in transfer switchs but they default to shore power if the generator stops.

My transfer switch is defaulted to shore power, if no power is anywhere. If I plug in to shore power, no switching and nothing changes.

When I start my generator, it runs a timer for 20 to 30 seconds while the generator stabilizes and then transfers to generator power, even when plugged in to shore power.

If my generator is producing power, the MH is using it. That's basically how the all work.

[Podivin]

I agree with twinboat (as always). The DEFAULT for the switch box is shore power, PRIORITY is given to the generator.

If you're not plugged in and the generator is not running then the switch box is set to shore power (the default). When you start the generator the switch box will switch over to the generator, regardless of the status of shore power.

The way a generator guy explained it to me is that there is a spring in the switch box. If no generator power is present then that spring puts the switch box to the shore power side. When power is received from the generator the pressure of the spring is overridden (magnetically I believe, but don't hold me to that) and the switch box moves to the generator side. Lose power from the generator and the spring puts the box to the shore power side, even if there is no shore power plugged in.

[J. Frank]

I tore my transfer switch apart and tried to fix it. It had a relay that was closed to shore power in the un-energized state. When the relay was energized with 120 VDC it switched to generator power. The generator supplied the 120 VDC through a circuit board that was fried. The circuit board also had a timer that allowed the generator to line out for about 30 seconds before it switched. You would not want to allow the generator to send power to anything until the engine was running smoothly and good steady power was being produced. So I think all transfer switches must be built this way. I replaced mine with an updated model made by Intellitec for $75. So I would say, if the generator is sending power to the MH, the transfer switch is probably okay.

[AFChap]

When the points get burned/ pitted from switching with heavy loads on, they will stick. (Always shut the heavy loads down before changing the power source). I had one that would not switch to show power sometimes after running the genny. The cure was a couple of sharp blows with my fist or a rubber mallet. I would hear the loud click when it switched over.

[Dr4Film]

There is a difference between Default and Priority.

Most RV transfer switches will give PRIORITY to the generator meaning that if you are hooked to shore power BUT have the generator running the transfer switch will ALWAYS give priority to the generator and transfer from shore power thereby disconnecting it.

Whereas when there is nothing powered up or hooked up to the coach the transfer switch will be sitting idle in the DEFAULT position which is shore power.

I know of one transfer switch called an ESCO ES50M-65N which uses 120 VAC coils to activate the contactors that has both the shore power and generator power contactors in their open positions until it recognizes which one it needs to switch to. However, even this transfer switch gives PRIORITY to the generator over the shore power. This model of transfer switch tends to emit a hum at times due to using 120 VAC coils whereas other transfer switches that use 12 VDC to power the coils do not hum.

Dr4Film ----- Richard

[gatorcq]

get a meter and measure -

[Boat wrench]

Update on the transfer switch problem contacted the manufacturer (Esco) yesterday their tech department was very helpful talked me thru the test procedure turns out the board is bad they are shipping me a replacement for 39 bucks they were great to deal with