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donaldrfiske

Cummins generator

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Ok guys an update on this topic.. Mechanic friend stopped by to acess the generator problem. Generator is producing electricity back to ats the lines back there are hot on both sides of the buss bar but no electricity into coach. Again everything works fine when plugged into land line any ideas ??

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Not many choices.

You have confirmed 120 VAC on the IN side of the ATS.  Assume by "both sides of buss bar" you mean you have confirmed 12 VAC on the OUT side of the ATS.  BUT YOU NEED TO  VERIFY THIS, AS IT IS THE MOST COMMON FAILURE POINT BETWEEN GENERATOR AND 120 VAC MAIN BREAKER BOX. Those wires are hardwired to the coach main 120 VAC breaker box unless someone has installed some kind of protection device between them.  

Assume you have checked for power to the main breaker box main breakers to neutral and there is none.

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Like Brett indicated, there could be a separate CB for the generator, between ATS and main panel.  I'm thinking that your ATS is stuck open on the shore power.  I had one that did it on Generator & I could not get shore power!  

I have seen coaches that had a plug for generator & had to unplug to get 120v from shore power!  Used mostly in 24VAC coaches, but it can be done on a 12VAC.  The plug would be in your ATS compartment.

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So I disconnected the land line wires at the transfer switch and wired the generator line wires from the transfer switch into land line connection started up generator and have full power to coach so I'm thinking the switch is stuck in the land line position and not switching over to the generator position when it's started up ?? Any thoughts

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Carl, With the information just offered. I have to agree!  

I have to wounder where the OP measured the 120 volts / that where not present and thinking the control board had failed?

The OP could check the ATS activation coil for power, But I think there is a strong possibility the ATS contacts could be FUSED together due to a high current load  at some point.

 

Rich.

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Yes it sounds like time for a new auto transfer switch. 

Yes Carl I have had my Portable Surge Guard protect my coach several times. I like the portable because I can check power at a site without having to move the coach. I have had to check as many as 4 sites to find good power when I was at Thousand Trails parks.

Bill

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Prior to spending money, disassemble the ATS and clean the contacts.(smoother the better) They are not designed to switch when under a heavy load, doing so can burn them due to arcing. If this doesn't work,, the only thing you lost is time. Then you may begin spending money.

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My only question at this time is, why would both sides of the bus bar be hot?  With nothing going into coach? While on generator.

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Don't know but when I switched gen lines to shore power lugs on bus bar I had full power in coach so the contacts must be fused together not allowing the switch to go from shore to generator 

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Contacts could be fused together or, there is a little control board inside the ATS that senses when the generator is running, this triggers a time delay IC that in turn shunts a transistor which  triggers the relays to change from shore power to generator power. Any part if that circuit board that fails will cause the generator circuit to not transfer. Or the contacts on the generator side may have corrosion and or arcs enough to cause the power to not come up. You can turn off most of your AC appliances, crank the generator while still hooked to shore power, the time delay after starting the generator is usually set to 30 seconds. If the contacts are fused, then shore power will remain on even though the generator is running. If the control board is functioning correctly, the power from shore source will cease, now if this happens, the contacts on the generator side will be the culprit. This will let you know what part inside the ATS is bad. Unless you are very handy and can follow instructions well then repair of the ATS is not recommended, though some of us have repaired them in the past. A new ATS is not at all difficult to replace, and are usually not that expensive. I've bought many over the years on ebay for about half the price of RV stores, and had very few failures as long as the RV'er uses the proper protocol in making transfers.

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With the generator running and hooked to shore power the ATS makes a click sound and a little green light comes on the circuit board in about 30 seconds but the coach stays on shore power so I'm thinking it is the circuit board.i also tapped the mount the board is on a few times thinking if the contacts were stuck shut this might free the contacts up but that didn't happen thanks for your help. 

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On ‎11‎/‎5‎/‎2018 at 6:16 PM, kaypsmith said:

If the contacts are fused, then shore power will remain on even though the generator is running.

Time to replace the ATS. If the contacts are fused, and sounds like they are, the circuit breaker on the generator should open to prevent damage to the generator.

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Okay guys first thanks so much for all your interest and support in this problem!!  I did replace the ATS. and now everything operates as it should. Took the old ATS apart and the contacts were not fused together . WFCO the  Manufacturers tech support said it it was the computer board that's bad since the buss bar had power on the in and exit side of the bar at the generator connection.Hope that makes  sence. Thanks again for your help 

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