kohler ch25 voltage regulator

BRIAN10

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regulator was not putting out any charging voltage.. we discounted the ac input lines it ranged between 15 ac and 40 ac with different engine speeds.. we checked the regulator one side of the ac input is shorted to the dc output.. is the normal??
 

bertsmobile1

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yes
there are 4 diodes inside the rectifier
so between each AC and the DC you should show a short circuit with the probes on way and an open circuit with the probes the other way round
Between the AC & the case should be the reverse of between the AC & the DC + terminals
and open circuit between the DC & the case
Check the wires
If the rectifier is mounted into the plastic blower housing there has to be a ground connection between the body & the engine
Kohler like to use a brass strip from on of the mounting holes and a blower mounting hole to make the ground and this strip is prone to cracking through
When I fit one I make 2 jumpers to connect both rectifier mounting screws to 2 different ground points as that ground strap has been the source of most of the Kohler charging problems I have come across .
 

ILENGINE

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Bert's explanation would be correct for a full wave rectifier/regulator The Kohler 15 amp rectifer/regulator is a half wave rectifier, so two of the terminals are bonded. So you will get a dead short between two of the terminals no matter what direction you connect the leads. Seems like it is the left two terminals on those regulators.

Also like Bert mentioned the biggest issue with charging issues and regulator output is the lose of the ground because of the regulator is mounted in the plastic blower housing. some use a metal strap to connect the left regulator mounting screw to the blower housing mounting bolt below the regulator. So come from the factory with a simple ground wire with ring connectors on the ends.
 

bertsmobile1

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Bert's explanation would be correct for a full wave rectifier/regulator The Kohler 15 amp rectifer/regulator is a half wave rectifier, so two of the terminals are bonded. So you will get a dead short between two of the terminals no matter what direction you connect the leads. Seems like it is the left two terminals on those regulators.

Also like Bert mentioned the biggest issue with charging issues and regulator output is the lose of the ground because of the regulator is mounted in the plastic blower housing. some use a metal strap to connect the left regulator mounting screw to the blower housing mounting bolt below the regulator. So come from the factory with a simple ground wire with ring connectors on the ends.
I stand corrected
 

hlw49

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Kohler regulators have a surge protector in them and some times all you have to do is uplug them and plug them back in.
 

BRIAN10

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guys thank you for all of your reply's.... all were helpful will check my dad's wiring on his toro today...
 

VegetiveSteam

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regulator was not putting out any charging voltage.. we discounted the ac input lines it ranged between 15 ac and 40 ac with different engine speeds.. we checked the regulator one side of the ac input is shorted to the dc output.. is the normal??
With the engine not running but the key switch turned to the on position, how much DC voltage do you have on the violet B+ wire? It should read battery voltage.

If that violet wire did read battery voltage, did you have it connected to the voltage regulator when you were checking regulator output? The regulator has to see DC voltage before it will let any current flow.

One more thing. Were you checking AC voltage across the two wires or each wire to ground? It needs to be checked across the wires with the red test lead on one stator wire and the black test lead on the other stator wire. At 3000 RPM you should read a minimum of 28 VAC. There is no maximum. The Kohler manual will tell you to check AC voltage with the connector disconnected from the voltage regulator but if the AC output is borderline, I've found that checking the AC voltage with the connector plugged into the regulator can put enough of a load on the system to show a problem.
 
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