Generator Power Switch Failure

[Anne & Erik]

We have an Itasca Horizon with an Onan generator. Last week, the switch which redirects the generator's power to the coach failed and is being replaced (about $350). This very same switch failed and was replaced approximately one year ago.

Anyone know what causes this type of failure? Is it something I can prevent?

I may have inadvertently run the generator while the Invertor was turned on. Might that have burned out this switch?

Thanks, Anne and Erik

[Anne & Erik]

We have an Itasca Horizon with an Onan generator. Last week, the switch which redirects the generator's power to the coach failed and is being replaced (about $350). This very same switch failed and was replaced approximately one year ago.

Anyone know what causes this type of failure? Is it something I can prevent?

I may have inadvertently run the generator while the Invertor was turned on. Might that have burned out this switch?

Thanks, Anne and Erik

[dirko]

Hi Ho: You didn't say what part of the switch failed. I assume the contacts. If so, you need to make sure that the switch doesn't switch large loads. High currents pit the contacts and lead to failure. In other words, make sure the A/C or electric water heater or something similar is not on when starting the generator or turning it off.

If the switch is in a particular state the contacts aren't moving and can handle large loads without pitting.

Good luck, Dirk

[MaverickBBD]

Try starting the generator without any load and then switching load to it. Do the opposite prior to shutting it down. See if that helps.

[MrTransistor]

Hello Anne and Erik,

There is a rather cheep micro-switch inside the housing that has ˜Faston' (spade type push on) connectors connected to it. Odds are that either the ˜Fastons' have come loose or the micro-switch contacts are bad. Go ahead and open it up (make sure all power is disconnected, generator off, inverter off) and check for loose wires or connectors. If all seems in order you can check the micro-switch contacts with a volt/ohm meter.

I've had two failures of this transfer box. First time was a ˜Faston' that fell off the switch. Squeezed the ˜Faston' to hold tighter on the spade for the first fix. The second time was bad contacts on the micro-switch. Replaced with a brand name switch for the second repair and now keep this box as an emergency backup. I have a schematic of this box but I haven't entered it into CAD and created a .PDF of it. I see a project around the corner. I'll get it posted as soon as I can.

Always worried about connecting to a 50 Amp. pedestal with an open neutral (very, very bad), so I purchased and installed this unit.

Automated Engineering Corp.
AC Transfer Switch "AECS with ESP"
p.n. 10040A our cost for a demo unit was $549.00
from RT Enterprizes -- Ron 818-292-1268

This thing uses a microprocessor to qualify the incoming line to ensure that the ground, neutral, and both 120 Volt AC lines are good. If not, it won't energize the contactors and gives an error code that describes the fault. It has already saved our bacon once which I'm sure more than paid for the unit. A park had a 50 Amp. service with a high resistance neutral (caused usually by terminal arcing from not being tightened enough). Good luck.

[MrTransistor]

Here's the schematic. For a full size, go to Photos.

[Anne & Erik]

Mr. Transistor. Wow. You may very well be correct, but I'm afraid your knowledge level has left me in the dust. I will take a look at the diagram and talk with the service tech.

Thanks, Anne and Erik

[MrTransistor]

Hello Anne and Erik,

Ohhh....Kay....Fine. This schematic is for Winnebago part number 106071-06-000. Since it uses parts that are no longer available, the newer units should have a different part number. Same function, just different parts inside.