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Kohlor kt745 not charging

Discussion in 'Mechanic and Repair' started by Roger1955, Sep 24, 2017.

  1. Roger1955

    Roger1955 LawnSite Member
    Messages: 11

    I'm new at this so please understand.
    I have a kohlor kt745 that will not charge.
    1st. I tested the the terminals across the rectifier running high rpm's 38.1 volt ac
    2nd. I tested the b+ center wire got nothing
    3rd. I ordered rectifiers from a company the "first one was 3.6 dc",2nd didn't fit, 3rd 2.1dc. So I guessed bad recifiers
    4th. I bought one locale put on mowed grass battery dead
    7.2dc volts from that one, I hope someone can help me
    Always tested b+ to ground
    I always had a good ground, that I checked first. Please help
     
    Last edited: Sep 24, 2017
  2. ricky86

    ricky86 LawnSite Silver Member
    Messages: 2,123

    Get a reference voltage first. Turn the key on. Make sure all interlock requirements are met. You should have the same voltage, give or take 1~1.5 volts at the wire that goes to the B+ wire on the reg/rec. Unless, it has some asinine wiring setup, and it might. If you don't and it has a convention wiring setup, the problem is in the tractor end. Not the engine. You say you checked the ground. Run a jumper from the reg/rec to the negative post on the battery. Then you're sure.
     
  3. Roger1955

    Roger1955 LawnSite Member
    Messages: 11

     
  4. Roger1955

    Roger1955 LawnSite Member
    Messages: 11

    Thanks I'll try my ground again
     
  5. Roger1955

    Roger1955 LawnSite Member
    Messages: 11

    I put a jumper cable between rectifier and battery (per Rick86)
    Readings 37v AC between Ac and Ac,
    3.4v DC between B+ and ground
    What's the odds of 3 rectifiers being bad
     
  6. piston slapper

    piston slapper LawnSite Platinum Member
    Messages: 4,335

    You need 12v pos from the key to the Bt terminal on the regulator...the regulator won't turn on to allow it to charge the battery if there's not a minimum of 9 volts ...
    It has a zener diode in it that switches it on when it senses the right voltage..
     
  7. Roger1955

    Roger1955 LawnSite Member
    Messages: 11

    Ok piston slapper, I'll be sure I've got 12 v+ at b+ terminal thanks
     
  8. Roger1955

    Roger1955 LawnSite Member
    Messages: 11

    Piston Slapper, I guess your right,. I have no voltage at B+ terminal with or without switch on. I can see now why it wouldn't work. Can I run a wire from ( Battery to B+ terminal ) without frying something?
     
  9. Roger1955

    Roger1955 LawnSite Member
    Messages: 11

    Piston Slapper, I guess your right. Nothing on B+ with or without switch on. Can I run a wire from (battery to B+ terminal on rectifier) without frying something?
     
  10. piston slapper

    piston slapper LawnSite Platinum Member
    Messages: 4,335

    Sure...it shouldn't hurt anything..
    Check for a blown fuse.
     

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