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Topic: Could Not Transfer 120v to Coach from Generator (Read 1029 times) previous topic - next topic

Could Not Transfer 120v to Coach from Generator

I started my generator to give it its usual exercise.  It started fine.

But the "transfer switch/relay?" could not lock and connect.

The generator appeared to be running fine.  The voltages on the two legs varied from 0 to 120 on the Link 2000 as the switch recycled repeatedly to connect.

It's pretty hot here in El Centro.  Perhaps it will do better in the cool of the night.

Any suggestions?

best, paul
1999 U320 40' 1200 watts on roof. 12cf AC/DC Cold plate fridge/freezer. VMS 240 CL Honda Element

Re: Could Not Transfer 120v to Coach from Generator

Reply #1 –
"TAP/RAP" on the outside of the ATS.  If the points have been abused by switching under load, this will often (temporarily) free them up.

Long term, replace the ATS.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Could Not Transfer 120v to Coach from Generator

Reply #2 –
Quote
"TAP/RAP" on the outside of the ATS. If the points have been abused by switching under load, this will often (temporarily) free them up.

Long term, replace the ATS.

Never switched under load since I've had this coach. Against the law....

Not sure what an ATS looks like. I sounds like its on the passenger side at the end of the bed.

Is it the long (15 inches or so) red item with 3 cables connected to it?

One in the middle.

One near one end.

One near the other end.

best, paul
1999 U320 40' 1200 watts on roof. 12cf AC/DC Cold plate fridge/freezer. VMS 240 CL Honda Element

Re: Could Not Transfer 120v to Coach from Generator

Reply #3 –
Paul,
  The red thing sounds like the isolator. It's probably mounted on the engine side. The ATS is mounted under the bed on the inside. Here's a photo of each. The red one is the isolator.
jor

93 225
95 300
97 270
99 320

Re: Could Not Transfer 120v to Coach from Generator

Reply #4 –
Quote
The red thing sounds like the isolator. It's probably mounted on the engine side. The ATS is mounted under the bed on the inside. Here's a photo of each. The red one is the isolator. jor

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The good news: The ATS did switch this morning.

The bad news: 91v on one leg, 101v on the other.

I assume the repeated attempts to switch yesterday scarred the contacts and a new ATS is needed.

Any recommendations of a place to get a new ATS between El Centro / Albuquerque / Denver / Minneapolis?

best, paul
1999 U320 40' 1200 watts on roof. 12cf AC/DC Cold plate fridge/freezer. VMS 240 CL Honda Element

Re: Could Not Transfer 120v to Coach from Generator

Reply #5 –
Paul,

Most any RV dealer stocks ATS's.

STOP what you are doing!  If voltages are dropping from 120 to those values, you have the potential for a fire on your hands.

I would turn off the coach main breaker in the 120 VAC breaker box until you are sure you have "good power" for you appliances. 

 If you are safe working around 120 VAC, check voltage with generator ON at the "generator IN" terminals of the ATS and then the "OUT terminals of the ATS to 120 VAC breaker box". I doubt (and sure hope you don't) have that kind of drop within the ATS!!!
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Could Not Transfer 120v to Coach from Generator

Reply #6 –
Quote
STOP what you are doing!  If voltages are dropping from 120 to those values, you have the potential for a fire on your hands.

I would turn off the coach main breaker in the 120 VAC breaker box until you are sure you have "good power" for you appliances.

 If you are safe working around 120 VAC, check voltage with generator ON at the "generator IN" terminals of the ATS and then the "OUT terminals of the ATS to 120 VAC breaker box". I doubt (and sure hope you don't) have that kind of drop within the ATS!!!

My recollection is the voltage at the Link 2000 is normal when connect to the pedestal.

But I'll drive over to the RV to verify.

Later.

best, paul
1999 U320 40' 1200 watts on roof. 12cf AC/DC Cold plate fridge/freezer. VMS 240 CL Honda Element

Re: Could Not Transfer 120v to Coach from Generator

Reply #7 –
Looking at my original, I may have omitted refreshing an important factor. The voltage drop only occurs when the generator is sending volts. Right now its a nice stable 120v connect to the pedestal - on both legs.

When I tried the generator yesterday the ATS never actually switched. It attempted to do so repeatedly, with voltages appearing momentarily on both legs from very low to 120v. I was reluctant to let it try to connect so many times and stopped the gen.

Today its behavior was different. It did connect but with abnormal low voltages. 91 on one leg and 101 on the other. I shut it down fast.

I assume this is a result of scarred (high resistance) contacts. But what do I know? I'm a civil engineer, not an electrician ;o)

Thanks for your interest and help.

best, paul
1999 U320 40' 1200 watts on roof. 12cf AC/DC Cold plate fridge/freezer. VMS 240 CL Honda Element

Re: Could Not Transfer 120v to Coach from Generator

Reply #8 –
Paul,

Good-- would hate for your coach's ATS to become a "resistance heater".

You need to check the generator IN side of the ATS for voltage-- could also be checked at the connection box where generator wires into coach.  If voltage is really low, the ATS may be just fine-- it is not seeing enough voltage to "smartly" pull in the contacts.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Could Not Transfer 120v to Coach from Generator

Reply #9 –
Could it be that the voltage regulator on the generator is failing?  Check the output voltages from the generator.  A new regulator is $250. 
Regards,
Brett

'99 42' Foretravel Xtreme
'14 Brown Motorsports Stacker
'05 Chevy SSR
'02 BMW R1150R

Re: Could Not Transfer 120v to Coach from Generator

Reply #10 –
Quote
Could it be that the voltage regulator on the generator is failing? Check the output voltages from the generator. A new regulator is $250.

My generator started as usual, and ATS locked in smartly. But the voltage varied on both legs from 91 to 130 or so.

I got my handy volt meter out but could not see where to check voltage at the generator.

Anyone have any nice photos? 1999 U320 10KW

best, paul
1999 U320 40' 1200 watts on roof. 12cf AC/DC Cold plate fridge/freezer. VMS 240 CL Honda Element

Re: Could Not Transfer 120v to Coach from Generator

Reply #11 –
Quote
Paul, Does the generator engine run smooth and steady or does it surge up & down ? If steady, would sound like a regulator or wiring issue as in a loose neutral wire for example. If engine is unsteady, then look for why it is hunting. Air in fuel line like a leak, etc.

Starts right up and is steady as usual.

To hot to go out there today. I'll look for loose wires in the AM

best, paul
1999 U320 40' 1200 watts on roof. 12cf AC/DC Cold plate fridge/freezer. VMS 240 CL Honda Element

Re: Could Not Transfer 120v to Coach from Generator

Reply #12 –
Paul,

Check voltage at output side of circuit breaker in control box.  A burned resistor on the left side of the regulator is a sure sign of regulator failure.
Regards,
Brett

'99 42' Foretravel Xtreme
'14 Brown Motorsports Stacker
'05 Chevy SSR
'02 BMW R1150R
 

Re: Could Not Transfer 120v to Coach from Generator

Reply #13 –
Quote
Check voltage at output side of circuit breaker in control box. A burned resistor on the left side of the regulator is a sure sign of regulator failure.

I took my trusty Radio Shack voltmeter in hand and tried to do the above.

Then I discovered a voltmeter needs a battery to work. A small 12v battery! A little smaller than a AAA. I'm thinking that battery might cost more than a new voltmeter from Wally World.

More later...

best, paul
Quote

Regards,
Brett
1999 U320 40' 1200 watts on roof. 12cf AC/DC Cold plate fridge/freezer. VMS 240 CL Honda Element