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IOTA ITS-50 R Auto Transfer Switch Maintenance

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I have religiously performed annual maintenance on the ATS on my 04 HR Endeavor  during the nine year that I have owned the coach.  The maintenance has included checking the tightness of the connections on the terminal block located in the ATS enclosure, visual of components and spot checking connections with infrared  heat gun. To date I have found no loose connections or signs of overheating or elevated temperature that would indicate poor connections.

This year I decided to perform a more detailed inspection which included removing the ATS from the coach (required to remover terminal block, locking tab on rear) and then removing the terminal block from ATS to provide access to check all connections on the relays and the relay contacts. Also have to remove 2 pop rivets to remove terminal block. This is required to access 4 of the connections that are not accessible with terminal block in place.

To my surprise I found all connections tight and only minor pitting on relay contacts. The pitting was cleaned up with 1000 grit sand paper and cleaned with electrical contact cleaner.

The relays are DELTROL 900 (US made) replacement ones are readily available , however they are made in China.

The first picture is with terminal block in normal position, second one is with terminal block positioned to access relays.

My coach also has a 50 Amp Hubble plug on the shore connection where it penetrates the bulkhead of the compartment  where you will need to check connection on both the male and female sides.



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11 hours ago, RayIN said:

Yep, and #2 is switching power sources under heavy load.

F___, that looks like a new terminal block assy.

I always make sure that there is little or no load when connecting or disconnecting shore power or when starting or stopping the generator.

The terminal strip and all components are original. The manufacturers spec sheet on the Series 900 Deltrol relays used in the ATS specify that they are designed for 100,000 operations. I expect that IOTA is not the only brand of ATS that uses them.

After just going thru my ATS I'm confident that the IOTA components are as robust as you will find in other brands.

I have spent my entire career in power generation and have found Deltrol components to be quality products.

Products are only as good as on how the end use maintains and uses any product.



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I previously mentioned in my original post that replacement relays were readily available. Initial response from local Deltrol supplier was that relay was available, however he now finds that it is no longer in production and is unable to find distributors  that may have old stock.

I contacted Deltrol directly and they informed that the relay in question was a special production for ATS manufacturer and that they do not manufacture any relays that cross reference with the same specifications. The difference in relays currently in production with the same current readings, physical dimensions  and coil voltages  have different timing in the pull in and drop out characteristics, which effects the current interruption capability.

I have requested the design specification from Deltrol for the original relay so I can determine if other relay manufacturers.

I have researched replacement ATS's and have only found a few that offer switched that have terminal  block to make connection. The length of the wiring between the ATS and breaker panel is really short and is not long enough to reach  termination on individual relays.

Will keep you posted.


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