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No Generator Power?


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1 hour ago, homelesshartshorns said:

If 140 is too high on generator line at the ATS will that mean the switch will not jump?

No that would not prevent the ATS from working. It is too high, if accurate. If you have shore power available, measure that just as a check for the accuracy of your meter. 

1 hour ago, homelesshartshorns said:

What exactly would cause the generator to produce too high of a reading?

The Onan control circuitry provides the voltage and frequency control. Circuit boards in it. I suggest that you troubleshoot 1 problem at a time. 

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1 hour ago, homelesshartshorns said:

Picking your brain! If 140 is too high on generator line at the ATS will that mean the switch will not jump? Does that mean I should look over the generator first? What exactly would cause the generator to produce too high of a reading?

Good questions but a bit above my pay grade absent detailed diagrams, but I will throw out some very basic best guesses: My background is more along power distribution and general RV electricals versus electronics and voltage regulation systems which is complicated and controlled with the circuit board.

 1) Its my OPINION if the genny were consistently producing 140 VAC which is on the high side (assuming an accurate reading??) that would NOT prevent the ATS from switching. It senses when genny voltage becomes present and typically AFTER a time delay it will toggle. If thats a bit high my best guess is it wont matter. NOTE with no load and open circuited I can envision voltage being on the high side until such time load current flows causing the control board to bring voltage within tolerances and if that 140 is temporary but not when a load is applied (at which time it comes down to 120) its not such a concern  BUT I DONT HAVE ANY DIAGRAMS OR EXPERIENCE TO KNOW FOR SURE   NOOOOOOOO WARRANTY 

 2) For sure if its actually producing 140 VAC consistently over time (NOT just brief transitory until voltage regulation circuitry takes over) I would be calling tech support and performing some troubleshooting as called for in the owners manual.

NOTE it also makes a difference if you genset were an Inverter style (which I doubt) versus the old school typical RPM voltage and frequency based. Those can run a bit on the high side (RPM frequency and voltage) until a load is applied which supports my guess 140 would NOT stop the ATS from toggling 

3) Again the excitation voltage and current which regulates the gensets output voltage is most likely contained within the control board which is wayyyyyyyyyyyyy above my pay grade and expertise.

 Of course I'm hesitant to advise you that a new ATS is needed BEFORE all other possibilities are exhausted including simple basics like a bad connection !!!!!!!!! That being said, just above I described the situations when a new ATS IS REQUIRED. Theres just too many variables and unknowns plus not being there to run my own tests that I cant diagnose your problem over the net. Maybe others here can and great if they do but I'm not confident in telling you FOR SURE whats needed other than what I said above  SORRY.

John T  Headed to Lecanto Florida I will check back later

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John is correct that the 140 volt output, although too high, would not affect the ATS operation. ONAN calls for a 132 VAC max no-load voltage and and a 112 VAC minimum full-load voltage for most non-inverter 60 Hz models. The frequency range should  be 63 Hz max at no load and 58 Hz min at full load. If the voltage reading is stable, then the voltage and frequency are adjusted using the idle stop screw and the governor speed adjustment nut. Again this applies to non-inverter models. If the voltage is varying with no change in the load, then the voltage regulator module is suspect. The service manual for your generator model will have more detailed information on testing the electronics.

Edited by Dutch_12078
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3 hours ago, Dutch_12078 said:

then the voltage and frequency are adjusted using the idle stop screw and the governor speed adjustment nut.

Dutch, Good info, Ive had lots of experience on Onans as well as Generacs (Non imverter style) using those two adjustments, they work pretty well and are easy peasey to tweak. Maybe the OP simply needs to adjust his governor speed to achieve 120 VAC (as RPM increases Frequency as well as volts increases) but that isnt going to fix any ATS problems OR SIMPLY BAD CONNECTIONS !!!!!  Those ATS screw down wire terminals (or wire nuts) have been known to come loose !!! The relay contacts can get carboned up and resistive likewise...

As always nice sparky chatting with you

John T  Now in Lecanto and Inverness Florida area..Warm n Sunny days cool nights great for dry camping

Edited by oldjohnt
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1 hour ago, homelesshartshorns said:

Ok thank you one an all for your suggestions and tips! It turns out it was the ATS, and I have it fixed....

Congratulations !!!!!!!!!!!!! Thanks for the update.........        I always hope for, try and suggest the cheap easy KISS fixes FIRST, but if all else was good then as suspected you were left with a bad ATS   WELL DRATS lol usually happens its a more expensive cure (*&^%%$#

 You did good

 John T

 

Edited by oldjohnt
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