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Chris1055

Rebuilt starter generator still not charging ?

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Hi

 

so I picked up this nice 855. And I love these little short frames. It wasn’t charging. So I figured I get a rebuild kit. Couldn’t hurt plus I got the bearings. I thoroughly cleaned it replace the field coil , brushes, posts and cleaned armatur. Put juice to it ran strong. Put it back on the tractor started fine but am only getting a half a volt on the generator. I did that polarizing test still not getting a big voltage. I’ve been cleaning wires and double checking the wire Diagram but these old tractors are very straight forward. Could it be the regulator ? Could it be the armature? I don’t know I’m stuck. But I would think even with the regulator disconnected I should be getiing like 15 volts out of it right?

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With the regulator disconnected you will get no voltage out put as the field coil isn't grounded. With engine running ground the F Terminal of the generator see if you then get some voltage output.  if you do get voltage up around 14 v then you have a regulator issue.  No out put then means something is still wrong in the generator....

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As Paul said, without the regulator there is no feedback to the S/G. No need to polarize the S/G. This diagram could be helpful.

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3 hours ago, pfrederi said:

With the regulator disconnected you will get no voltage out put as the field coil isn't grounded. With engine running ground the F Terminal of the generator see if you then get some voltage output.  if you do get voltage up around 14 v then you have a regulator issue.  No out put then means something is still wrong in the generator....

So I read the Kohler pdf it’s got very good point and I pulled it apart and checked everything again. I still have no voltage at the output of the generator. So my guess is the armature but my question is how if the armature is bad wouldn’t it not crank??

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I am no expert in Starter Gens but if i read this correctly the field shunt makes it generate.  The other field is the primary for starting with the shunt field just helping. if the shunt field is bad,, no generation.  My S/G guy explained to me once he had to replace the "generator" field coil in one of mine to get it to work.

shunts.JPG

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I had already re placed both the field coils they are new 

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Sorry, by me at this point.  (I outsource my Starter Generator work :P)

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This information from Brian Miller's site may be helpful.

Information on Kohler (and most small engines) Charging Systems - Top of page

First of all, the battery's only purpose in virtually any vehicle is to provide power to the starter motor to crank the engine and power electrical accessories when the engine isn't running. When the engine is running, and while the battery is being recharged, the alternator or generator then powers the electrical accessories through the voltage rectifier/regulator. With the engine running, and with a good working charging system, the battery has nothing to do with powering the electrical accessories. The ignition system also have nothing to do with the charging system. It's only purpose is to provide spark to the engine. The charging system and ignition system are two totally separate systems. One has nothing to do with the other, other than the charging system provides power to the battery-powered ignition system. A magneto or solid state ignition is a stand-alone system. It does not depend on the battery or charging system whatsoever.

The Generator Charging System -

The voltage-producing generating part of a starter/generator (or just the generator unit in an older automobile or heavy equipment machinery) produces DC (direct current) electricity. These are belt-driven and require a mechanical voltage regulator to regulate the charge to the battery and power electrical accessories (such as lights, electric PTO clutch, etc.) at the same time. The faster the engine runs, the more voltage and amperage the generator produces. And unlike a belt-driven automotive-type alternator, the generator is self-energizing. It will produce its own electricity when spun fast enough. A charged battery is not required.

Although bulky, heavy and uses more space next to the engine, this system is reliable, but produce little- to no-charge at low idle speeds and are considered obsolete by today's standards. Also, this system require more horsepower from the engine than the alternator system while recharging the battery and/or under a heavy electrical load.

The correct way to connect the wires on the starter/generator is as follows...

  • Two wires connects to the [bigger] "A" (Armature) terminal on the starter/generator:
    • A minimum 8 AWG wire connects from one of the big posts on the heavy duty starter switch or starter solenoid/relay to the [bigger] "A" (Armature) terminal on the starter/generator. This connection cranks the engine.
    • A 16 AWG wire connects from the "A" (Armature) terminal on the voltage regulator to the [bigger] "A" (Armature) terminal on the starter/generator. (A smaller gauge wire can be used, but #14 is recommended for durability.)
  • A 16 AWG wire connects from the "F" (Field) terminal on the voltage regulator to the [smaller] "F" (Field) terminal on the starter/generator. (A smaller gauge wire can be used, but 16 is recommended for durability.)
  • Mounting base of voltage regulator must be grounded to engine or tractor frame.

 If either of the smaller wires is connected to the wrong terminal, the field windings inside the starter/generator will burn up instantly upon engine start up! But somehow, the starter/generator will still crank the engine. (Odd... ???) See the drawing to the right for wiring instructions. ä

A starter/generator can be adapted to virtually any horizontal shaft or vertical shaft small engine with a fabricated mounting bracket and a slotted adjusting brace to tighten the belt. The starter/generator will need to be installed opposite the carburetor side of the block. They come in two rotations: clockwise and counter-clockwise. Starter/generators that spin clockwise came on older Wheel Horse, Sears Suburban, Bolens, or any engine that's started from the flywheel end. A counter-clockwise starter/generator came mostly on older Cub Cadets, or any engine that's started from the PTO end. A clockwise rotation starter/generator will need to be used if it's driven from the flywheel end. But if it's driven from the PTO end, it will need to be a counter-clockwise rotation starter/generator. If the wrong starter/generator is used, it'll crank the engine opposite of normal rotation, and not recharge the battery.

If a starter/generator is belt-driven by an engine and used only as a generator to charge up a vehicle's battery and/or power 12 volt appliances or lights, the heavy battery cable won't need to be used. And there's about a 3:1 ratio between the starter/generator and engine. This means the starter/generator spins about 3 times faster than the engine. So the pulley on the engine will need to be about 3 times bigger than the pulley on the starter/generator to adequately recharge a battery and/or power 12 volt electrical appliances or lights. A starter/generator require a minimum 7/16hp engine running at a governored 3,600 RPM for it to produce a regulated 15 amps @ 13.5 volts. (15 amps x 13.5 volts = 202.5 watts x 2 = 405 = .4hp engine.) Read on the back label of the appliance you plan to use for how many amps it draws, then you'll know if the generator will be able to handle the load.

But on a pulling tractor, if the engine isn't going to have a charging system, a voltage regulator and wiring isn't required as long as the battery is fully charged with a remote battery charger before the engine is ran again. Plus, the battery will need to be in a secure place, and route the wiring in a safe manner. Go here to learn how to repair a Delco-Remy starter/generator: Delco-Remy SG Repair.pdf(require Adobe Acrobat Reader and use Google Chrome web browser for a faster download of web sites with large files.)

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Thank Richard i was looking for that Delco-Remy Service manual  ( I like to be able to understand what my S/G guy explains to me.)

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Thank you guys for helping me out! I’ll keep you posted I’m going to tear it apart tonight and do a couple of test !!

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Hi guys. So while looking into the generator. I’m currently re wiring this tractor. I’m going to put a solenoid in it as the diagram above shows. My question is I have a old style 3 prong switch that has bat, start, and ing. Where do I put the wire that goes from battery on the regulator to?? On the diagram above it shows it going to r on the switch that I assume is run. On mine they had it going straight to the battery.

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R on the switch is for Regulator.  With a 3 pole switch you could piggyback on the ignition.  Best not to have it connected to battery directly could run the battery down if something goes wrong in the regulator

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1 hour ago, pfrederi said:

could piggyback on the ignition.

Paul, not too sure that will work. with the engine running and the charging system functioning I think the key being turned off would not turn off the engine because the charging system would continue to supply voltage to the coil if you did that. The "B" battery terminal from the regulator is connected to the battery on the older S/G including the three wire ignition switch units.

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43 minutes ago, 953 nut said:

Paul, not too sure that will work. with the engine running and the charging system functioning I think the key being turned off would not turn off the engine because the charging system would continue to supply voltage to the coil if you did that. The "B" battery terminal from the regulator is connected to the battery on the older S/G including the three wire ignition switch units.

 

Good point.  you are correct.

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Posted (edited)

Hey guys. So I just want to update you on my progress. You know it’s funny I’ve worked on a lot of tractors and it’s always fun learning more about things when you think you’ve got it down. I’ve decided to install a starter solenoid underneath the dash. I really don’t like drilling holes on the tractors but I think putting in a solenoid in the older models is just a better safety feature. I pulled the generator back apart and checked everything out seemed ok. Then I tested the regulator and found out it was shot. I orders a new regulator it’s a little different then the old one in the mounting. But seemed to bolt on ok with a little bend of the tabs. Hooked everything up and surprisingly it charged. I thought could it of really been that simple and why wasn’t it producing any voltage without the regulator on. Oh well I’m happy. So now off to bigger and better thing such as maybe adapting the old mounting backet for the reg and cleaning up the old Delco  cover.  I also will fix my wires but I was in the testing stage. 

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Edited by Chris1055

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1 hour ago, Chris1055 said:

I orders a new regulator it’s a little different then the old one in the mounting. But seemed to bolt on ok with a little bend of the tabs. Hooked everything up and surprisingly it charged.

:woohoo:

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Posted (edited)

is the 16.00 volts the battery voltage ?, that regulator will quickly overcharge and cook your battery if the battery voltage goes that high

Edited by RubyCon1

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While your at it. Replace that cable on the solenoid. Looks questionable. One of the first things I do when I acquire an old tractor.

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The 16 volts is on the generator. And the wiring is going to be replaced it was only for testing purposes.  Thanks for the input guys always have my back greatly appreciated!!

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Posted (edited)
11 hours ago, Chris1055 said:

The 16 volts is on the generator.

so what is the voltage across the battery terminals, as neither voltage you show in your pics is a good charging voltage.

remember- the generator is directly connected to the battery thru the regulators cutout relay

Edited by RubyCon1

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Across the battery is between 12.5 to 13.5 volts never lower. I’ll post a pic . I ran it today for a long time and the battery didn’t drop any voltage like it did before. I’m certain it’s charging 

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