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mooman3121

effects of reverse polarity

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mooman3121

Hi all!  I recently purchased a 702 that had been sitting in a barn for several years. It was not in running condition at the time so I only paid attention to the major things- motor turn, trans shift, body condition, etc. When I got the machine home and actually started cleaning and disassembling I discovered that the new then battery had been hooked up backwards! Wow no wonder the guy couldn't get it to run- Now that I have it running I don't think that the generator is working as I only get a faint glow on my tester coming out of it when running. My question is could the battery being installed backwards have damaged the charging system and if so how? I priced a new regulator and it wasn't cheap, so would like any help on what to do.... Thanks!

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pfrederi

Generators need to be polarized. That is accomplished by flashing the Armature terminal to battery voltage.  However as you have a Starter Generator that is done automatically when you start it.  You are applying battery voltage to the armature terminal.  Voltage regulators can fail from corrosion bad contact etc.... 

 

What is battery voltage when shut down?  Should be 12.6 for  fully charged battery

 

Voltage when running?? Should about 14. 

 

Take a jumper wire and ground the "F" terminal on the generator You should hear the engine slow a bit and voltage should jump up to 14.  if it does then you r regulator is bad.  if it doesn't then the charging field  coil is suspect

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stevasaurus

Hi...thought this would be better served in the "Engine Section".  I'm not sure if the guy hooked it up backwards and never ran it...if it would cause any harm.  Looks like Paul  jumped in before I showed how little I know.  Listen to what Paul says.  :orcs-cheers:

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pfrederi

Generators do not care if they are positive or negative ground (think old farm tractors) Hence the requirement to flash polarize them. Current saddle mount regulators say pos or neg ground (not sure about the ones from 40+ year ago0.  The PO of my Farmall M put a battery charger on it for several days back wards...(She is positive ground).  other than screwing the battery did no harm to the generator or cutout regulator.

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mooman3121

Ok thanks all! I had never experienced this kind of deal before- Am well aware of positive ground systems but didn't know if special components required as I am definitely not a sparky!  thanks again..will check it out and let you know what I find.....

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953 nut

Be sure to clean and tighten all electrical connections including grounds. A little corrosion can make a big difference.

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mooman3121

I hear ya 953! but some of those terminals on the back certain components you KNOW that you will not remove without twisting off! spraying lots of blaster every day! Think connection is still good but- yes would like to be sure! thanks!

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mooman3121

yes! :lol: for sure!  should have seen the work to adjust the clutch and brake! deserves a :wacko: times two ! yep! by the way how does one ever disconnect that clutch shaft that goes to the other side of the frame without totally disassembly? newbie wonders....

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Achto

@mooman3121 Check psep.biz for a voltage regulator if you need one, they have after market ones for around $20. It will be in the Kohler/ starter section. 

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mooman3121

Thank you much Achto for that! was quoted way more for that regulator! :)

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mooman3121

Ok- did the test Paul recommended , voltage at rest not running was 12.5- voltage when running drops to 12.2. When I ran jumper wire from the field pole to ground it had no effect- voltage stayed at 12.2 and engine was unaffected. So must be the generator itself has the issue? 

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pfrederi
2 minutes ago, mooman3121 said:

Ok- did the test Paul recommended , voltage at rest not running was 12.5- voltage when running drops to 12.2. When I ran jumper wire from the field pole to ground it had no effect- voltage stayed at 12.2 and engine was unaffected. So must be the generator itself has the issue? 

Assuming all the wiring is OK no bad or corroded connections then it is most likely a failed field coil (or something else internal to the Genny.)  Note the regulator may still be bad also

 

I do most of my own mechanical work but Generators go to a local Starter generator shop. Undercutting an armature is not in my skill set. They will also insure that your regulator is OK as both regulator and Genny may have failed.

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mooman3121

Hey Paul!  Yes I took apart and cleaned all the connections before testing so while I am bummed that I now have to send it out and spend money on it, at least it will eventually get working right again! thanks for your help!

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