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Topic: 1996 U270-36 Possible failure of automatic transfer switches at foot of bed (Read 614 times) previous topic - next topic

1996 U270-36 Possible failure of automatic transfer switches at foot of bed

I juust started my 8kw generator to no avail. No lunch either.
Was hoping to run the SHARP microwave. Nope no power to it. Checked all breakers

What is the easiest way to determine if it is GENERATING any power OUT of the auto transfer switch?

QUESTION.. Is the microwave power coming from receptacle in the small compartment above it?

Running the microwave previously, it seemed to take about 40-50 seconds for it to sound like it was up to full power.
Not normal.

Regards
Jon Twork

Re: 1996 U270-36 Possible failure of automatic transfer switches at foot of bed

Reply #1 –
Are you getting 120 volts at the voltmeter with thr generator running.

Re: 1996 U270-36 Possible failure of automatic transfer switches at foot of bed

Reply #2 –
Quote from: Jon Twork –
QUESTION.. Is the microwave power coming from receptacle in the small compartment above it?
Answer:  On our coach, YES, microwave is plugged into outlet in cabinet above.

Generator:  There should be one or two circuit breakers on the generator panel - check those are not tripped.

From the generator, power goes to the ATS that switches between GEN and SHORE power.  If you are comfortable working around 120V when hot, you can take the cover off the ATS to expose the internal bits.  Look for any sign of loose or overheated connections.  Check for "burned wire" smell.  If everything looks good, fire up the generator.  With multimeter, check the contacts coming into the ATS, and the contacts going out.

One set of contacts going into the ATS should be HOT - those would be the generator leads.  The contacts going out should also be HOT if the ATS is working properly.



Re: 1996 U270-36 Possible failure of automatic transfer switches at foot of bed

Reply #3 –
Quote from: Jon Twork –
Running the microwave previously, it seemed to take about 40-50 seconds for it to sound like it was up to full power.
Not normal.
Is your microwave the original factory installed?  If so, it may have finally died?

Re: 1996 U270-36 Possible failure of automatic transfer switches at foot of bed

Reply #4 –
Yes, after turning both on-generator breakers OFF and back ON the next step is to check for power IN and OUT of the ATS. But, only if you are safe working around 120/240 VAC.

To test the ATS, with shore power disconnected, generator off, inverter off:

Remove the lid.

Check wires for sign of burning.  Check that all screws are tight.

Plug in and turn on shore power.

Check both IN and OUT for:
Black to white= 120 VAC
Red to white= 120 VAC
Black or red to green= 120 VAC
Black to red-- if on 15 or 30 amp will read zero.  If on 50 amp will read 240 VAC

Repeat with shore power disconnected, generator running.
 

Re: 1996 U270-36 Possible failure of automatic transfer switches at foot of bed

Reply #5 –
Quote from: wolfe10 –
Yes, after turning both on-generator breakers OFF and back ON

When turning breaker off, after moving  to the off position,  try pushing the breaker handle towards the off side.  Sometime breakers if tripped will not reset until they have been pushed in the off direction after being turned off.  If you hear a click when pushing it towards the off means that there is a good chance that that breaker was tripped. 

Can not tell you how many service calls I have made over the last 50 years just resetting breakers that the customer said they had already resent them.