AEC 10040 problem

[eagle bus]

I have a Automated Engineering Corp auto transfer switch with ESP (model 10040) that doesn't work as designed (they are no longer in bussiness). When hooking up to shore power it will not transfer until I turn off my inverter (Xantrex SW2512). After turning off the inverter and reconnecting the power it will change over. The inverter can then be turned on and everything will work fine.
I once talked to someone from the company that said to install a light or resister to the switch but for the life of me I can't remember how. Has anyone else had this issue or heard of it? Thanks for any help. Hal

[RV Wizard]

Hello Hal and . We are glad to have you join us here and we look forward to reading of your adventures and experiences. I am sure you will enjoy the website and forums. Good luck and keep us posted.
I am not sure if this particular model has been a topic of discussion here or not but you could do a "search" to find out. Also if you could include some coach info in your signature; this helps everyone to know specifics with out you having to enter it each time.

[Gary RVRoamer]

Sounds to me as though the inverter output circuit is somehow feeding back into the transfer switch an causing the ESP to balk. That would suggest a wiring problem in your coach rather than a problem with the ATS/ESP. Do you have a remote display for the ESP? Is there an error code displayed?

TRC Surge Guard has picked up the AEC transfer switch product line and now sells it as the Surge Guard #41260 and #40250. I don't know if they would help with your model or not.

[eagle bus]

Thanks for the information Gary. I gave them (TRC) a call and they were no help at all. Although it is a two year old unit they acted as it was an antique. They offered no ideas but did suggest I buy a new unit from them.
I tend to agree there may be a neutral/bonding issue and will pursue it that way. Thanks again, Hal

[RV Wizard]

You might want to look at the inverter. If it is putting out a modified sin wave when there is incoming shore power, the transfer switch inside the inverter may not be changing over. It should be passing the ac current through and not in a inverting mode. What happens when you use the generator?

[eagle bus]

Its a true sine wave unit (Xantrex SW2512) and it acts the same on either power source. I may have to add a relay to open the neutral/bonding in the inverter. This may be the issue. Hal

[Luv2go]

Xantrex (Trace) SW2512's are pretty particular about how you wire ATS's and generators to them. For example, they do not like switching between shore power and generator without a 100ms delay between disconnecting one source and connecting another.

There is a separate input for generator on the inverter that you are supposed to connect the generator to.

After reading about the TRC 40250 ATS here (p8) it looks like it may provide the required delays.

Xantrex seems to have done away with their SW2512 manual but Kyocera still has it. Note this is the non-MC (motorcoach) version, the MC version has different firmware but identical hardware.

The SW2512 does not operate like most other inverters, it actually has the ability to backfeed the line (think grid tie solar applications) so the power topology is totally different from your run-of-the-mill inverter/charger. The firmware in the MC version disables this feature.

There should already be a relay to open the neutral-ground bond of the inverter, i.e. the inverter neutral should only be shorted to ground when there is no shore or generator power. Maybe that relay has gone bad?

Good Luck!
Stewart

[eagle bus]

Thanks Stewart, you seem to be quite versed about this inverter.
This is a new unit I just installed after my Trace 2512 died-operator error by getting it wet. I bought the Xantrex in 2006 when I heard Xantrex would be phasing it out and have had it on the shelf ever since.
I had the same issue with the trace and was told by ATC tech to add a resistor somehow (crs?) to the ats to cure the problem. I didn't do it at the time for one reason or another but would love to make it work now.
The Xantrex manual says to instal a relay to break the neutral bond. You are right in that they show the genset connected to the inverter and also show internal relays.
I may have to consider rewiring using the inverters ats and using the ATC unit as pass through protection without the switching feature.
Thanks,Hal

[Luv2go]

Hal, thanks for the kind words. Much of what I learned about Trace inverters comes from Sean at Our Odyssey. I've corresponded with him a couple of times as well as studying his detailed web pages on his installation.

My installation is a bit different than his, I have the inverter powering the entire coach, it replaces the ATS. The ATS was re-purposed to provide the Neutral to Ground bond when running on inverter (it takes advantage of the generators neutral to ground bond to do so).

I had to add a relay to bypass the inverter on one leg when we were connected to 50A to take advantage of the 50A feed. I also added a relay to the ATS in a way similar to Sean's to restore generator priority, and allow the generator to work with the AGS feature of the inverter at low battery.

Unfortunately I do not know how or where to add a resistor the the ATS to correct the problem. I do believe if your ground to neutral bond is not disconnected when on shore power the ATS won't work right (as well as causing potential safety issues by having neutral current return on the ground path). Add that to the fact that you can actually break your SW2512 by transferring too fast means I'd recommend rewiring.

Do you have a schematic or wiring diagram of your wiring?

Here is a schematic of my AC wiring. Please feel free to ask questions if you decide to rewire and want more details.

Stewart

[eagle bus]

Thanks Stewart again. After rethinking things I realized using the inverters ATS couldn't work. I have the genset wired 240 volts which would require a stacked set of inverters. I'm planning to use a pair of relays to open the bonded neutral in the 2512. I'll have to control each relays' coil off the gen/shore contactors primary side in the ATS, series wiring the bond through both relays (inverter neutral to grd leg bond) so either source will open the bond.
All I have to do is find a couple of relays ,DPST with NO and NC contacts. I have to find an NEC to check but I think a #8 wire will work for the bonding jumper.Thanks again,
Hal