Walk behind SW36A-15KH DC output voltage

JjEjFjF

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I have an SW36A-15KH pull start walk behind serial number 8050437 with the kohler command pro 15 CV15T spec # 41581. Can anyone tell me what the DC output voltage to the clutch should be? This mower had a bad pto clutch in it when i bought it last week. I replaced the clutch and noticed that the DC voltage going to the clutch was rather high. At full throttle it can get up as high as 25v. Kinda high for a 12v clutch. I tried 3 different rectifier regulators , all giving the same readings.Am i having incredibly bad luck with a rash of bad regulators? Someone on youtube suggested the "capacitor" was maybe bad. His mower has the kawasaki motor on it so i dont know if the something specific to kawasaki or not. All i know is mine didnt come with one and it doesnt show one in the wiring diagram. Here are the three rectifiers that i tried. The original one that came on it 12 403 01 , superseding the original
12 755 111-S , sten 435-563. Al supposedly the same thing.The The first two i had tested with the kohler rectifier regulator tester and both show "high" on the results. Ill be taking the third to be tested today.Any info will help. Thanks.
 

bertsmobile1

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the regulator rectifier should cap the output voltage to around 14-15 V DC
The AC voltage between the two white ( or yellow ) wires should be around 36 V AC
It is rare to have that sorts of over voltage .
When playing with a used mower things get complicated.
So start with the AC voltage.ON Kohlers the AC goes to the outside terminals and the DC comes out of the middle ( purple ) wire.
Both the A & DC ground through body of the rectifier so make sure the earth strap is connected to one of the regulator mounting bolts .
I am a belts & braces man so I kake up 2 of them and ground out to both of the rectifier mounting bolts.

A lot of Kohlers get fitted to bobcats & loaders etc that have heavy power power loads so the DPO could very well have fitted a wrong stator.
I have even seen one wired up wrong because the DPO measured more volts on the white wires so he fed them directly into the battery .
 

JjEjFjF

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Thanks for the reply. When testing the AC output (between the two ac terminals) the voltage can get as high as 46volts at full throttle.Full throttle on this mower probably exceeds the recommended rpms suggested for testing. And about 10v ac at idle. The rectifier is grounded good. I cleaned up of the connections.Im very anal about good connections.I could add another ground for good measure i suppose. Like i said in my original post , I had all 3 of the rectifiers checked using a kohler tester , all 3 of them showed "high" on the tester. I dont know if its a fluke that i happened to get 3 bad rectifiers or if the stator on the mower is ruining them.
 

bertsmobile1

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Thanks for the reply. When testing the AC output (between the two ac terminals) the voltage can get as high as 46volts at full throttle.Full throttle on this mower probably exceeds the recommended rpms suggested for testing. And about 10v ac at idle. The rectifier is grounded good. I cleaned up of the connections.Im very anal about good connections.I could add another ground for good measure i suppose. Like i said in my original post , I had all 3 of the rectifiers checked using a kohler tester , all 3 of them showed "high" on the tester. I dont know if its a fluke that i happened to get 3 bad rectifiers or if the stator on the mower is ruining them.

46 volts AC is too high
46 V AC = + 23V & - 23V
Thus when rectified will give you 23 V DC ( minus electrical losses ) which is way too high.
So my thoughts is you have a wrong or defective stator.
Kohler say 26 to 32 V AC.
I have no idea what the mowers use to regulate the voltage.
Because they are trying to keep costs down some might use the power demand of the various bits on the mower , ditch digger, loader etc to put a heavy enough load on the output to drag it down.
In any case your output is way too high .
Now this can be because the engine is running too fast or because there is a miss match between the stator & rotor.
Kohler only seem to have one casting for their flywheels so a lot of them are interchangable but the size & number of the magnets on the inside varies from one model to another.
 

JjEjFjF

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46 volts AC is too high
46 V AC = + 23V & - 23V
Thus when rectified will give you 23 V DC ( minus electrical losses ) which is way too high.
So my thoughts is you have a wrong or defective stator.
Kohler say 26 to 32 V AC.
I have no idea what the mowers use to regulate the voltage.
Because they are trying to keep costs down some might use the power demand of the various bits on the mower , ditch digger, loader etc to put a heavy enough load on the output to drag it down.
In any case your output is way too high .
Now this can be because the engine is running too fast or because there is a miss match between the stator & rotor.
Kohler only seem to have one casting for their flywheels so a lot of them are interchangable but the size & number of the magnets on the inside varies from one model to another.

Thanks again. Its absolute insanity that a guy cant get an answer from anyone. The tech support guys from manufacturer of the mower dont even know how their machines are supposed to operate. Kohler will not talk to any peon end user, they just pass you off to your local "kohler specialist". Well my local "specialist" didnt want to know a thing about my mower because its not the brand they sell even though i went to see them about the motor itself not the whole machine. The manufacture of the rectifier regulator wont talk to peons either. They pass you off to you local "dealer". Well according to them, my local dealer is a small town hardware store owned and operated by two old ladies who dont even sell lawnmowers let alone work on them. Absolute insanity.
Today i pulled off the flywheel to get a look at the stator and hopefully get some numbers off of it. No numbers on it. I tested as best i knew how from watching videos and from the manual. Between the 2 leads from the stator i get .4 ohms resistance. According to the manual thats good.I checked for shorts and found none.The stator is in good shape except for a little surface rust on the parts the face the magnets. There are 6 large magnets in the flywheel.Theres about a quarter inch gap between each magnet. All are fastened as they should be.As far as i can tell none of the magnets have been reglued on. I did here of a guy who re glued a magnet back on upside down and really caused havoc.
This mower uses a rectifier regulator all in one.(supposedly) . When looking around the internet , some places describe it as a 12v rectifier/regulator and others call it a rectifier. Even the people who are selling them have no idea about them. All they know is what their told. Very sad.
As you mentioned , the motor does run a little fast at full throttle but to get the voltages down to acceptable levels , it has to be way down around 1/4 throttle. Way too low to mow reasonably.Im willing to buy a stator and yet another rectifier regulator if it going to be a sure fix. I never thought about flywheel being the wrong one.Hopefully thats not the case if i do get a new stator.Everything a mystery with kohler so im not sure how to get any info on the flywheel.
 
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JjEjFjF

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46 volts AC is too high
46 V AC = + 23V & - 23V
Thus when rectified will give you 23 V DC ( minus electrical losses ) which is way too high.
So my thoughts is you have a wrong or defective stator.
Kohler say 26 to 32 V AC.
I have no idea what the mowers use to regulate the voltage.
Because they are trying to keep costs down some might use the power demand of the various bits on the mower , ditch digger, loader etc to put a heavy enough load on the output to drag it down.
In any case your output is way too high .
Now this can be because the engine is running too fast or because there is a miss match between the stator & rotor.
Kohler only seem to have one casting for their flywheels so a lot of them are interchangable but the size & number of the magnets on the inside varies from one model to another.
I have a new stator and regulator coming. Ill see what happens. Both parts are oem and specific the the spec of the motor.
 

bertsmobile1

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Thanks again. Its absolute insanity that a guy cant get an answer from anyone. The tech support guys from manufacturer of the mower dont even know how their machines are supposed to operate. Kohler will not talk to any peon end user, they just pass you off to your local "kohler specialist". Well my local "specialist" didnt want to know a thing about my mower because its not the brand they sell even though i went to see them about the motor itself not the whole machine. The manufacture of the rectifier regulator wont talk to peons either. They pass you off to you local "dealer". Well according to them, my local dealer is a small town hardware store owned and operated by two old ladies who dont even sell lawnmowers let alone work on them. Absolute insanity.
Today i pulled off the flywheel to get a look at the stator and hopefully get some numbers off of it. No numbers on it. I tested as best i knew how from watching videos and from the manual. Between the 2 leads from the stator i get .4 ohms resistance. According to the manual thats good.I checked for shorts and found none.The stator is in good shape except for a little surface rust on the parts the face the magnets. There are 6 large magnets in the flywheel.Theres about a quarter inch gap between each magnet. All are fastened as they should be.As far as i can tell none of the magnets have been reglued on. I did here of a guy who re glued a magnet back on upside down and really caused havoc.
This mower uses a rectifier regulator all in one.(supposedly) . When looking around the internet , some places describe it as a 12v rectifier/regulator and others call it a rectifier. Even the people who are selling them have no idea about them. All they know is what their told. Very sad.
As you mentioned , the motor does run a little fast at full throttle but to get the voltages down to acceptable levels , it has to be way down around 1/4 throttle. Way too low to mow reasonably.Im willing to buy a stator and yet another rectifier regulator if it going to be a sure fix. I never thought about flywheel being the wrong one.Hopefully thats not the case if i do get a new stator.Everything a mystery with kohler so im not sure how to get any info on the flywheel.

That is why we have dealer networks.
Kohler make over 1,000,000 engines a year.
If 0.1% of them have problems that is 10,000 service call a year from people who many time can not even identify a part correctly.
Thus the amount of time spent just trying to work out what the customers problem is would add $ 200 to the price of every new engine.
Now to make life easy for the end customer , Kohler have their service manuals available on line for free.
OTOH you can walk into a dealers shop with the suspect part in hand & be sorted out in 15 sec.
The down side is corperate chains who are run by accountants and thus only want to sell new equipment as that is the most profitable thing to do.
Mowers are seasonal so the shops that rely on retail sales only have a 3-4 month window to turn over their full years profit so spending a hour in the hope of making $ 5 profit on a couple of parts is not on.
Seek out a repair only shop, down the back streets with no big glossy showroom and a lot of serviced used mowers on the street for sale.

Magnets need to be glued in alternate poles N-S-N-S-N.
 

JjEjFjF

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That is why we have dealer networks.
Kohler make over 1,000,000 engines a year.
If 0.1% of them have problems that is 10,000 service call a year from people who many time can not even identify a part correctly.
Thus the amount of time spent just trying to work out what the customers problem is would add $ 200 to the price of every new engine.
Now to make life easy for the end customer , Kohler have their service manuals available on line for free.
OTOH you can walk into a dealers shop with the suspect part in hand & be sorted out in 15 sec.
The down side is corperate chains who are run by accountants and thus only want to sell new equipment as that is the most profitable thing to do.
Mowers are seasonal so the shops that rely on retail sales only have a 3-4 month window to turn over their full years profit so spending a hour in the hope of making $ 5 profit on a couple of parts is not on.
Seek out a repair only shop, down the back streets with no big glossy showroom and a lot of serviced used mowers on the street for sale.

Magnets need to be glued in alternate poles N-S-N-S-N.

What would happen if the magnets were wrong? Something like N-N-S-N-S-N.
 

bertsmobile1

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What would happen if the magnets were wrong? Something like N-N-S-N-S-N.

You burn out a pair of coils.
The coils are connected 180 deg apart to give you the -+-+-+-+-+-+-+-+ Ac voltage so you get the same situation as installing the batter backwards.
 

JjEjFjF

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You burn out a pair of coils.
The coils are connected 180 deg apart to give you the -+-+-+-+-+-+-+-+ Ac voltage so you get the same situation as installing the batter backwards.

And then the stator will quit producing altogether?
 
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