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Kohler 12.5RCOP63 Spec. 96603C Serial 010774


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  #1  
Old 02-05-2019, 04:30:01 PM
Rjvega Rjvega is offline
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Default Kohler 12.5RCOP63 Spec. 96603C Serial 010774

Hi All,

I am searching for a schematic, parts list, troubleshooting/operators manual for this setup. I have a paper copy of the Maintenance Manual if someone needs something from there. Nowhere in the manual does it describe the controller box at all.

This GenSet was new in 1979. I hope it is old enough to interest this group.

Some wires near the start switch burned and I am hoping to rewire it and to understand why it burned. I have photos





Here are some specs that I feel fairly confident on:

On TAG
DPA 3248F990
Serial # R42372ZT
Model # PH30/500/9/188

Model # 12.5RCOP63
12.5 kVA
R - Remote control Start/Stop
C - Push Button Start at plant 12 V Electric Start?
O - Diesel
P - Perkins Engine
6- ?
Last number 3 - Marine

Kohler Generator Set (Discontinued)
Model # 12.5RCOP63
Spec: 96603C
Serial # 010774
KW 12.5 PHASE 1
KVA 12.5 HERTZ 60
VOLTS 120/240 RPM 1800
AMP 52 PF 1
WT #BATT 1
150-350cca

I tried to include these photos:
https://www.dropbox.com/s/clqxrho92a...Front.pdf?dl=0

https://www.dropbox.com/s/gfks153cac...amage.pdf?dl=0

The original receipt for this set " ES-795, 12.5RCOP63, Spec 96603L"
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  #2  
Old 02-05-2019, 07:39:48 PM
jack0 jack0 is offline
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Default Re: Kohler 12.5RCOP63 Spec. 96603C Serial 010774

Check out the frequently asked Kohler questions.
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Old 02-05-2019, 08:23:39 PM
Zephyr7 Zephyr7 is offline
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Default Re: Kohler 12.5RCOP63 Spec. 96603C Serial 010774

That selenium rectifier may have failed. Classic problem with the old sets. You can replace it with a silicon bridge rectifier. Note that other things often fail when those old rectifiers fail so you need to check the rest to be sure.

Bill
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Old 02-06-2019, 12:34:27 AM
Rjvega Rjvega is offline
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Default Re: Kohler 12.5RCOP63 Spec. 96603C Serial 010774

That selenium rectifier may have failed. Classic problem with the old sets. You can replace it with a silicon bridge rectifier. Note that other things often fail when those old rectifiers fail so you need to check the rest to be sure.

THANK YOU for the reply. Do you know how I spec the new bridge rectifier? or where to acquire it?
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Old 02-06-2019, 12:53:25 AM
Zephyr7 Zephyr7 is offline
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Default Re: Kohler 12.5RCOP63 Spec. 96603C Serial 010774

All the bridge rectifiers are cheap. I’d go for a 25A or larger, 1000 PIV unit. It’ll probably be maybe $5 max. You can get 35A and 50A sizes too. Larger won’t hurt for ampacity. Good sources are digikey, mouser, and all electronics. Jameco is another option.

Bolt the rectifier to the metal chassis somewhere inside the control cabinet. The metal box will help with heatsinking for the rectifier.

Remember that when the rectifier fails, it often takes other parts with it so you need to check the components connected to the rectifier too.

Bill
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Old 02-06-2019, 01:24:04 AM
Rjvega Rjvega is offline
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Default Re: Kohler 12.5RCOP63 Spec. 96603C Serial 010774

Great. I have both reviewed the FAQ (thanks jack0) and checked into a replacement rectifier THANK YOU Zephyr7. As recommended by the FAQ, I wrote to a distributor asking for the wiring diagram based on the info I had in my post. I will post what I receive.

I will need the schematic diagram to check what downstream damage might have been done. I'm hoping I receive something from the distributor.

In the meantime, I will test the Selenium Rectifier to see if it has failed. Will the increased efficiency of the new rectifier cause me any issues?

Is reworking this controller the optimum path? Are there aftermarket controllers that could work?
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Old 02-06-2019, 02:17:16 AM
Zephyr7 Zephyr7 is offline
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Default Re: Kohler 12.5RCOP63 Spec. 96603C Serial 010774

Replace the selenium rectifier even if it still checks good. They’re all timebombs just waiting to fail. I doubt the better efficiency will cause you any problems, but check the generator output after you replace the rectifier since you’ll probably need to adjust the voltage.

I don’t have schematics for your particular genset, but it shouldn’t be too difficult to just trace the wiring from that rectifier to check connected components.

Bill
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Old 02-06-2019, 12:09:00 PM
Rjvega Rjvega is offline
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Default Re: Kohler 12.5RCOP63 Spec. 96603C Serial 010774

I wrote to Colburn Power Systems (service@colburnpower.com), provided the info I had about the GenSet and received the schematic within 12 hours. This indicates that I have Controller D-268950

https://www.dropbox.com/s/mcswf9hveb...13386.pdf?dl=0

I also found this article about Selenium Rectifiers that seemed really good. I read that the addition of a 100 Ohm resistor to a replacement rectifier will get the output voltage very close to what the Selenium Rectifier was.

https://www.dropbox.com/s/af0je3k7gd...nium2.pdf?dl=0

Happened across this Service Bulletin describing the replacement of relays from available service kit. The 233180 relay is used twice and the 233059 is used once in my controller.

https://www.colburnpower.com/mwdownl...d/link/id/118/
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  #9  
Old 02-06-2019, 03:54:45 PM
Rjvega Rjvega is offline
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Default Re: Kohler 12.5RCOP63 Spec. 96603C Serial 010774

It appears that the wire for the start switch, both in the control box, and in the remote panel burned. The one on the remote panel burned from the start switch to a remote voltage meter. Does this point to the Selenium Rectifier?
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Old 02-06-2019, 05:22:51 PM
Vanman Vanman is online now
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Default Re: Kohler 12.5RCOP63 Spec. 96603C Serial 010774

The selenium rectifier is used to supply power to the auxilliary field winding, in proportion to load current. To do this it is in series with a transformer and the line. The load current then passes though the secondary, consisting of a few heavy turns.

This is why it is critical that the rectifier not go open circuit. If it does, the transformer develops a very high voltage, destroying itself.

The lower voltage drop of the silicon rectifier will merely make the output voltage *slightly* higher under load. Extra resistance is not needed here, and would introduce another potential failure point.

The control wiring is not interconnected with the auxilliary field circuit, however, on my set, it was unfused and found with similar issues to yours when I got it. I added fuses to key places during the overhaul.

Do NOT add a fuse or anything else in series with the auxilliary field, it's rectifier, or it's transformer.
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