Kohler part number OUCH!

[chuckd]

Trying to get out of town and fighting getting the right part for my Kohler 12.5 kw generator.  Finally (maybe) have the right part coming.  I sent to Kohler my schematic, and a picture of the transformer removed from the generator.  They did not have the schematic but they recognized the transformer and are sending me same.  Will have it on Tuesday.  The ouch - it is a smooth $940!!!!!!

Not many options then to get out card and pay same.

Chuckd

[Barn Owl]

$940!!!! Wow! How much would it have cost to have your transformer rebuilt at a motor shop? Most items like that are usually not custom built for the manufacture because it is much less expensive to use components that are commonly found. If you knew the specs there might have been a good chance to find a replacement. Transformers are fairly simple devices.

[boogiethecat]

Would you post your schematic and the transformer photo here? I'm sure there's a way to get around spending that kind of money on Kohler, but I'd like to get an idea of what it does before I say more... but it looks like you've already ordered it so maybe too late. Unless the thing weighs 100 pounds I can't imagine a transformer should cost that much....
Cheers
boogie

[Sean]

Chuck, now I am confused.

The last time we discussed this, in a different thread, you said you spoke to Kohler and the transformer was $147.  Was that the wrong part?

-Sean
http://OurOdyssey.BlogSpot.com

[Sean]

... I'd like to get an idea of what it does before I say more...

Gary, I am guessing (as I wrote in the other thread) that this is the transformer that derives the exciter voltage.  I am further guessing that this is a transformer-regulated set.

Original thread here:
http://www.busconversions.com/bbs/index.php?topic=18490

-Sean
http://OurOdyssey.BlogSpot.com

[oldmansax]

I posted this on the Wanderlodge board in a thread concerning rebuilding my 12.5 Kohler. It may be helpful here:

I found out some interesting info today on Kohler generators. Maybe this is already well known but it was news to me.

My son works for the HVAC division of a company that has one of the largest motor rewinding shops in the country. For some reason I didn't even think to ask him about rewinding my stator.... I had a senior moment I guess. Anyway my son called that division & talked to the head of the shop. He's been there about 40 years. He said Kohler has used many, many different manufacturers for the generator heads over the years, They have a terrible reputation, not so much for construction or service, but within the manufacturing community. They evidently will use a manufacturer and make them replace generators that fail, whether or not it was a manufacturing problem. Finally the manufacturer gets fed up & refuses to honor frivolous claims & Kohler will switch to another supplier. They have done this at least every 2 years since this guy has been in the business. He said sometimes the manufacturer doesn't last 1 whole year. The end result of this is I was wasting my time to try to find used parts to match what I have unless they were made (year wise) pretty close together. He said buying something that matches mine would be pretty much dumb luck!

(cue Clint Eastwood "You look dumb, but are you LUCKY, PUNK!") 

TOM

[luvrbus]

Maybe they should stick to bath tubs ,toilets and etc seem to do a good job at that lol

good luck

[chuckd]

Greetings all:

Just got back last night from Washington DC, where I was honored to be present at my son's promotion ceremony, as he was promoted to the rank of Colonel in the United States Army.  It goes without saying that his father is very proud of him.

Here is a picture of the old transformer, that was removed from the genset, and the new one they shipped.  (the wrong one).  I sent this picture to them and they recognized the part and are sending same to me.  This transformer is located on the output of the ac generator, and I think it is some kind of noise suppression or spike prevention or ?.

Chuckd

[boogiethecat]

Interesting photo.  Doesn't seem to be anything special, definitely nothing that makes me think it should be worth more than a hundred bucks...
If this were mine, I'd think seriously about taking it apart, counting the turns carefully and either rewinding it or having a new one made from scratch. There are places that will do it..

I'd also  seriously think about why it failed.  Transformers are one of those things that just don't usually fail unless they are either seriously under-rated for the job they are doing, or something downstream seriously overloads them. Not to say they are totally immune to failure, just that a transformer simply failing on it's own while operating normally within it's design and temperature limits is a fairly rare occurrence.  Usually it's an outside influence that overloads and thereby overheats it, causing it's insulation to fail.
That said, and to give the benefit of doubt, it does look like it was the primary side (high voltage coil) that went poof... maybe it was just a poor job of manufacturing...

Can you post the schematic, or email it to me?  I'd like to see what it actually does in the system, and maybe can then recommend something (for next time) that will work and be more reasonably priced...

Update- I took a look at the schematic and as Sean guessed, it's a transformer-regulated-field kind-of-circuit, with two current-sensing windings that would not translate to a transformer that you'd find "off the shelf."  My guess if it's getting hot is because the load is either poor power factor, too high overall on both legs or maybe too unbalanced, or a combination of these.  It's just a guess.  In an ideal situation you have a 12.5KW generator and you'd be using 6.25KW max on each leg, at a power factor close to 1.  If there's more than that being drawn on a leg (and correspondingly less on the other) or your load has a lousy power factor, it could theoretically overheat one or both of the transformer's windings... and it'd also probably be trying to toast the armature winding too.

It's probably easiest to just replace it- I was thinking it might be a fairly standard 120-to-some-lower-voltage transformer but it's not.  Maybe the cheapest bet would to be buy oldmansax's head on ebay!!!
Rewinding it also would not be out of the question if you had time and patience, and a few tools. It wouldn't be a project for the shy, but for as much as they want for a new one I'd be trying it if it were myself!!! It couldn't cost you more than 20 bucks worth of magnet wire to try...

[oldmansax]

Greetings all:

Just got back last night from Washington DC, where I was honored to be present at my son's promotion ceremony, as he was promoted to the rank of Colonel in the United States Army.  It goes without saying that his father is very proud of him.

Here is a picture of the old transformer, that was removed from the genset, and the new one they shipped.  (the wrong one).  I sent this picture to them and they recognized the part and are sending same to me.  This transformer is located on the output of the ac generator, and I think it is some kind of noise suppression or spike prevention or ?.

Chuckd

There is one just like it on the generator I have for sale on Ebay. I'll bet the whole thing goes for less than that transformer.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=300515600534&ssPageName=STRK:MESELX:IT

TOM

[desi arnaz]

i would buy a new geni if i was you. there are some used 20k on ebay for $2995.00