Kohler Generator With Automatic Transfer Switch

[GlennSullivan]

For those of you with Kohler Generators equipped with Kohler automatic transfer switches. Specifically all versions of the Kohler RDT:

During the crazy storms in the past 2 weeks, one day we had Utility power go off and on about 10 times in as many minutes and drove the ATS controller crazy (they are programmed for follow a specific process in the start up, transfer, transfer back, cool down and shut down process. Evidently when they receive constant back to back conflicting conflicting commands, they just quit.

After the storms cleared I was left with a functional generator that would start if I set it to manual start, but the ATS would not send or maintain a start command.
I diagnosed the problem down to the controller card in the ATS. Kohler dealers wanted anywhere between $800 to $1050 for a replacement and days to weeks for delivery.

Spent some time searching around and found a company that not only repairs these cards for $275.00 + roundtrip freight, but also makes a new and improved model card for $375 that is much less likely to fail. I purchased the new and improved card and they shipped the same day I placed the order.

I installed it and it works perfectly. One thing to note is the card I received was jumpered to 50hz when of course anywhere in NA should be 60hz. Good thing I put the cards side by side before installing.

For those of you with Kohler RDT transfer switches, here is a good and inexpensive source for repairs and / or spares for the controller.

The Kohler Part # is GM35950L (I'm sure there are many variations of the letter designation)
Flight Systems Part # is 72-GM35950-00

 

[wyliesdiesels]

sounds like the settings need to be updated. change the timer for the "on-utility" time before transfer back to utility to a higher setting to prevent such an occurrence....

 

[GlennSullivan]

Yeah, I think setting the transfer time from generator back to utility delay needs to be more like 10 minutes. That and this better designed and built board will probably keep me from going through this again.

 

[nadogail]

Sometimes the utility is not ready for everything connected to be transferred at once. I used to have to load the system intermittently until they had increased the firing rate on the power plant boilers before they could take the 200 Horsepower motor load without causing a frequency drop on the feed to my load.

 

[GlennSullivan]

Sometimes the utility is not ready for everything connected to be transferred at once. I used to have to load the system intermittently until they had increased the firing rate on the power plant boilers before they could take the 200 Horsepower motor load without causing a frequency drop on the feed to my load.

Your thoughts are very understandable with an industrial load and when I was in that world with 2000amps @ 440 we would stay on generator power for hours after the utility came back up, monitoring their feeds.

This is a home level 200A service and I want it to be able to think on its own when we are not here. Between you and me, I belive the reason for the on / off / on / off is they were testing repair work. Wylies prolly has a good Idea in setting the controller to wait a longer period after it sees utility power restored before switching off generator power.

The controller is not smart enough to measure voltage or frequency deviation so I have to give it time based commands to go on and the standard Kohler programing obviously don’t work in todays world.

Thankfully the aftermarket card I found makes it easy to change these settings with a laptop and a null modem cable.