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Kohler engine CV15T rectifier

#1

A

avtuvy

I have a John Deere G15 mower with a Kohler CV15T engine. The DC voltage between leg B of the rectifier and ground is 38V, I thought it should be 12V DC, why is the voltage so high?
The PTO works fine


#2

G

geelee

your mower has no battery, so your rectifier is changing ac directly to dc . so 38v is right. you dont have a regulator. your just powering the pto clutch


#3

A

avtuvy

Thank you for the quick response. I want to add a starter to the mower, it seems like the engine is set for it and the "ignition" key has a starter position.
Is it possible to get a 12V DC from the rectifier and still keep the PTO working maybe by using a different rectifier?
What is the voltage required by the PTO?


#4

StarTech

StarTech

geelee said:
your mower has no battery, so your rectifier is changing ac directly to dc . so 38v is right. you dont have a regulator. your just powering the pto clutch
Click to expand...
Are you nuts? 38 VDC will fry the PTO clutch in short order. IF you took the time to look-up the JD G15 you would have seen that the Kohler is using a rectifier/voltage regulator setup. The output DC voltage should be no more than 14.5 VDC.

PLEASE don't guess at things unless it is your own equipment.

To OP replace your voltage regulator.


#5

A

avtuvy

What is the reason for the 38V at the B+ leg of the rectifier? the spec for the PTO says that it is a 12V PT and works correctly, my voltmeter also works correctly


#6

S

slomo

avtuvy said:
What is the reason for the 38V at the B+ leg of the rectifier? the spec for the PTO says that it is a 12V PT and works correctly, my voltmeter also works correctly
Click to expand...
Sounds like the rectifier to me. Those change the spinning rotor/armature from AC to DC voltage. Voltage regulators keep that said voltage at a constant level (battery voltage). Sounds to me like battery voltage level is needed per StarTech.

I don't know exactly what the OP has for a charging/power generation setup. Just stating the obvious about those parts.

Listen to StarTech word for word. (y)

slomo


#7

StarTech

StarTech

Going by the IPL the OP has either a Kohler CV15T-41631 or CV15T-41633 but there is a third CV15T but its spec isn't listed.


#8

G

geelee

I see none of you have worked on rectifier only systems that have no battery, that directly power ptos. 38v at no load, when pto is on it will drop to the proper range


#9

StarTech

StarTech

So you think those 15/20 amp stators is going to drop that much voltage. I have look-up both of the specs I listed from the IPL and they both uses the same stator. They also are using a halfwave rectifier setup with a 15 amp voltage regulator.


#10

A

avtuvy

geelee said:
I see none of you have worked on rectifier only systems that have no battery, that directly power ptos. 38v at no load, when pto is on it will drop to the proper range
Click to expand...
That engine is also used for the CV15S variation which has an electric starter and charges a 12V battery, the schematic for that engine shows a connection between leg B+ of the rectifier through the ignition switch to the battery for charging. Does it use a different stator or rectifier?


#11

G

geelee

if you add a battery then you need to replace the rectifier with a rectifier regulator. stator is the same


#12

StarTech

StarTech

Posting the engine spec would resolve the question of what was used on the engine but as I said the two engines list by spec number for the JD G15 both had 15/20 amp stators and half wave rectifier / voltage regulators.

Yes I actually look up both engines on Kohler Plus and wasn't just guessing at the info. I hate it when someone just posts something without even taking the time to actually look up things. That is like me telling the Amaco transmission shop that I need the fluid and filter changed in 700R4 in my '79 Malibu. Instead looking they just wanted to argue with me. I won a $20 bet plus a free fluid and filter change for it as I was the one that put the 700R4 in it. Boy that was a nice steak dinner.


#13

G

geelee

if it has no battery is a rectfier only. a regulator needs at least 4volts at b+ to work. i know that the rectifier only system is not even mentioned in the service manual but its in use on several manufacturers


#14

A

avtuvy

Below is a response that I received from Kohler regarding the same question, they also refer to a Joh Deere spec# 27509, where can I find this spec and a wiring diagram?

"So I’ll bet this is a Wide Area Walk Behind (WAWB) mower which has a recoil starter and an electric PTO clutch. In this application, we only use a rectifier, as opposed to a Regulator/rectifier. This uses an Unregulated charging system. It is normal to have a seemingly high amount of voltage in such cases. This is because there isn’t a battery to use as any kind of “power reserve”, so to speak."


#15

StarTech

StarTech

Then I wonder why they have a 25 403 37-s listed as the correct unit on their parts lookup on Kohler Plus. And then what is the correct Kohler PN?
1624452718923.png
1624452481776.png


#16

StarTech

StarTech

And before someone says the voltage regulator will not work without a battery I just tested one here and the output voltage only when up to 19 vdc (not zero output as Kawasaki Regulator do) without the battery or anything else attached to the regulator except for DVMM. This was on a CV20-65577 which uses the same regulator as above.


#17

A

avtuvy

StarTech said:
And before someone says the voltage regulator will not work without a battery I just tested one here and the output voltage only when up to 19 vdc (not zero output as Kawasaki Regulator do) without the battery or anything else attached to the regulator except for DVMM. This was on a CV20-65577 which uses the same regulator as above.
Click to expand...
Is 19 vdc normal, is it safe to connect to a battery for charging and also operate the PTO at the same time?


#18

StarTech

StarTech

avtuvy said:
Is 19 vdc normal, is it safe to connect to a battery for charging and also operate the PTO at the same time?
Click to expand...
Once I reconnected the battery to the circuit the regulator when back to 14.7 vdc which is within spec for battery charging. And yes both can be connected as this is a 15 amp setup. Your PTO should not draw more 7.5 amps max with normal range around 3-4 amps.


#19

A

avtuvy

StarTech said:
Once I reconnected the battery to the circuit the regulator when back to 14.7 vdc which is within spec for battery charging. And yes both can be connected as this is a 15 amp setup. Your PTO should no more 7.5 amps max with normal range around 3-4 amps.
Click to expand...
Thank you


#20

G

geelee

so starr it seems kohler backed me up. ive only been doing this 48 years, wtf do i know . also you may want to read sb-174. you will read voltage but it wont power anything. and as i kept saying if it has no battery but never got an answer back


#21

A

avtuvy

geelee said:
so starr it seems kohler backed me up. ive only been doing this 48 years, wtf do i know . also you may want to read sb-174. you will read voltage but it wont power anything. and as i kept saying if it has no battery but never got an answer back
Click to expand...
Where can I find sb-174?


#22

StarTech

StarTech

geelee said:
so starr it seems kohler backed me up. ive only been doing this 48 years, wtf do i know . also you may want to read sb-174
Click to expand...
Well maybe they should keep their IPLs updated then with the correct info. Also these regulators do work with a battery not present as some changes apparently has been made the last 30 yrs.

But I can only go by the info Kohler provides in their IPLs. If an engine is spec to JD specs than then Kohler should be providing the correct info. And personally do know voltage regulators can be setup to self regulate without a load present or at least that is how my 12V 15amp power supply I built does.I personally also not seen the internal schematic of the Kohler voltage regulators so I don't if they got foldback current regulation or or remote voltage sensing.

avtuvy said:
Where can I find sb-174?
Click to expand...
1624478512605.png


#23

A

avtuvy

StarTech said:
Well maybe they should keep their IPLs updated then with the correct info. Also these regulators do work with a battery not present as some changes apparently has been made the last 30 yrs.

But I can only go by the info Kohler provides in their IPLs. If an engine is spec to JD specs than then Kohler should be providing the correct info. And personally do know voltage regulators can be setup to self regulate without a load present or at least that is how my 12V 15amp power supply I built does.I personally also not seen the internal schematic of the Kohler voltage regulators so I don't if they got foldback current regulation or or remote voltage sensing.


View attachment 57119
Click to expand...
Thank you


#24

StarTech

StarTech

geelee said:
so starr it seems kohler backed me up. ive only been doing this 48 years, wtf do i know . also you may want to read sb-174. you will read voltage but it wont power anything. and as i kept saying if it has no battery but never got an answer back
Click to expand...
Also while on the subject Kohler support they are wishy washy on things. First they said a two coils were under warrany and all I had to do just the engine model and serial number along with the bad parts to get them made up. Then when I tried several dealers they all refused to honor Kohler rep word. Then I call back to Kohler about getting them made directly they it the dealers decision if they wanted to honor Kohler's word. Well I not carrying a ZTR in from my shop to their just so they charge me diagnostic fee when I how the parts were bad. I discuss it with the customer and we both agree to buy the fail coils which I provided at cost. Since this problem with Kohler lying to me I refuse to buy anything else from the local dealers nor send any referrals.


#25

A

avtuvy

StarTech said:
Also while on the subject Kohler support they are wishy washy on things. First they said a two coils were under warrany and all I had to do just the engine model and serial number along with the bad parts to get them made up. Then when I tried several dealers they all refused to honor Kohler rep word. Then I call back to Kohler about getting them made directly they it the dealers decision if they wanted to honor Kohler's word. Well I not carrying a ZTR in from my shop to their just so they charge me diagnostic fee when I how the parts were bad. I discuss it with the customer and we both agree to buy the fail coils which I provided at cost. Since this problem with Kohler lying to me I refuse to buy anything else from the local dealers nor send any referrals.
Click to expand...
I was pleasantly surprised from their customer support, I sent a message through their web site and the next day I had a response, I corresponded with the customer service rep via email during the day with at least 10 messages going between us.


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