Generator AUX connection ... WFCO transfer switch failure

[twvette]

Thought one of my AC units was having issues as it sometimes would not run or struggle to run (similar symptoms as if had a bad capacitor as it would try to fire) and then finally would never come on. Long story short, found one leg of the WFCO T-57 automatic transfer switch failed as no power coming into the AC unit. Moved this AC over to the leg that my 2nd AC unit was on to get me through the trip and worked fine.

Anyways, ordered a new switch but what showed up is a T-57-R. Looks the same but there are no "AUX" connections on the terminal blocks like my T-57 has. I only have a wire going into the "Generator" block for AUX and all other AUX ("Power Cord" and "Control Panel" block) connections have nothing going to them. WFCO documentation on website does not even mention anything about having different T-57 models. I do see a T-57-P on the internet and some mention of the T-57-R being a replacement for it. Anyone know what the AUX connections do and/or if the "R" model is just the latest and somehow integrates them and if so where I now put the wire that was going to the Generator AUX connection?

I can give WFCO a call, but if nothing else wanted to document this experience.

[twvette]

Spoke with WFCO. The -R is just the latest version of the T-57 and not a separate model. Apparently the AUX connections are not needed on a 50A generator as they only have one neutral whereas some others (I believe they mentioned 70A generators) have two neutrals and this second neutral would go to the AUX connection. So, they removed the AUX connections on newer versions. Not sure why mine has a wire going to the Generator AUX connection and they suggested just moving it over to the Neutral connection. Perhaps it was just part of Keystone's standard wiring procedure to run this extra wire but really don't know. Will report back if any issues after doing this.

[twvette]

Just to finish this post off, wanted to confirm I replaced with the new T-57-R switch and everything seems to be working normal. it was essentially a direct transfer over without having to change anything except the AUX connection previously mentioned. All wires reached their connection slot without having to redo them either.

Figured out what the original Generator AUX connection does. Without it I could not turn both A/C units on at the same time, only one at a time. I just moved it into the Generator Neutral connection with the original Neutral wire that goes there too and can turn both on at the same time now. This makes further sense as also just realized the original switch had a permanent jumper in place between the Generator AUX and Neutral (Control Panel section had the same). It is easy to put both wires in the same connection block as these are smaller diameter wire so both fit easily.