Kohler 15RMY81

[stretch67]

Hello

Looking for manuals and info for a Kohler 15RMY81.

Thanks

Jeff

[Jack Hottel]

Here's a wiring diagram.
Jack Hottel

[stretch67]

Thanks for the information so far.

Wehave got the unit to run.
It will not make power.
It will make power if we flash the field with 12 volts but once the 12 volts is removed it will not make power.

Where should we start to look next?

Trouble shooting info would be great.

Thanks
Jeff

[Birken Vogt]

Most likely that voltage regulator PCB is no good and I don't think they are still available and Flight Systems does not repair them. Trouble is, it also includes the overspeed and it is for the low ohm Kohler rotor.

It could also be the SCR pack you see off to the side, or bad connections. The wiring diagram is pretty simple, just excite it with 12V and make sure voltage is making it to all the places it should be.

[stretch67]

Hello

Thanks for the info. I will pass it along
Will keep looking for more info.
not good news on the regulator being hard tpo find.

Thanks

Jeff

[Zephyr7]

Originally Posted by stretch67

Hello
Thanks for the info. I will pass it along
Will keep looking for more info.
not good news on the regulator being hard tpo find.

If the regulator is not potted, and you have some soldering skills, it is probably repairable. It’s usually either dried out electrolytic capacitors or power devices (transistors, etc) that fail. Resistors sometimes burn up, but those are usually easy to spot visually. For a repair, just replace the suspect parts (all electrolytic capacitors, all power transistors) and give it a try. Probably less than $20-30 in parts. Don’t even bother trying to diagnose anything. A lot of times a rebuild like this will fix things.

Don’t try this unless you’re certain the regulator board is at fault.

Bill

[stretch67]

Not a potted board.
Give the fact that the unit sat the last 10 years I a unheated shed, i am pretty sure that the card is going to need looking at. Only 70 hours on the unit.

Thanks for the help.

Jeff

[Zephyr7]

If you try the rebuild on the board, grab a can of conformal coating (techspray sells rattle cans of the stuff), spray everything except the adjustable part of pots and wiring terminals when you’re done. That should seal it from future moisture issues.

Bill

[Birken Vogt]

I'm pretty sure these boards had a similar coating when new, but the components just got old and gave up.

[Zephyr7]

Originally Posted by Birken Vogt

I'm pretty sure these boards had a similar coating when new, but the components just got old and gave up.

I would think so too, but I’ve seen some boards in old control cabinets that either had no coating, or the coating was damaged. I’m not sure what would strip the conformal coating off of old boards, but I’ve seen it before.

Bill