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  1. Replacement Varistor? 
    #1
    Junior Member
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    Oct 2014
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    Champlain Valley area, Vermont
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    MY brother-in-law is fixing up an E16 as a wedding present for my brother. I'm digging up some parts here and there.

    We have a small circuit board, about 1"x1" containing a few diodes, a varistor, 3 orange wires, and three black wires. (I'm not sure what the board does - fortunately, I'm not the one doing the repairs. Hopefully the diescription will give enough info for more knowledgeable folks to figure it out.) The varistor is blown, and no part numbers are readable on it. A guy 10 minutes down the road with a few old Elec-traks rummaged in a parts bin and pulled out an old Radio Shack varistor. He said it MIGHT be the right one to use. Can anyone help me figure out if it will work? The info from the package is below.

    Radio Shack part number 276-568

    Absolute Maximum Ratings
    RMS voltage: 130VAC
    DC voltage: 175VDC
    Peak Current: 6500A (8 x 20uS)
    Energy: 70 Joules

    Electrical Characteristics
    Varistor Voltage (minimum): 184V
    Varistor Voltage (nominal): 200V
    Varistor Voltage (maximum): 246V
    Typical Capacitance: 1900pF
    Rated Power: 1W
     
     

  2. Re: Replacement Varistor? 
    #2
    Junior Member
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    Champlain Valley area, Vermont
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    I guess this should have been posted in the "Problems" section, rather than the "How to do it" section?
     
     

  3. Re: Replacement Varistor? 
    #3
    Senior Member FarmallMan's Avatar
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    Location
    Schenectady, NY, USA
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    I think that would probably work. If you want, Jim at the Electric Tractor Store sells replacements: http://electrictractorstore.com/inde...products_id=63

    The varistor is there to clamp voltage spikes from the field windings. The diodes are there to provide field current from the contactors that are powering the motor's armature without back feeding (shorting out) anything.

    Nick
     
     

  4. Re: Replacement Varistor? 
    #4
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    Oct 2014
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    Champlain Valley area, Vermont
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    Thanks, FarmallMan. We're out of time to order a part. The wedding is Saturday, and we're caught up in travel and pre-wedding events. We're hoping to have at least the tractor operational by the wedding (we won't have even started on the snow thrower, but he doesn't need that right away anyway.)

    I guess we'll try this one and see how it works. Hopefully none of that magic black smoke that makes things run gets out when we try it... since everyone knows once the smoke escapes form inside of various circuit boards and black boxes, nothing works.
     
     

  5. Re: Replacement Varistor? 
    #5
    Senior Member FarmallMan's Avatar
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    I think it will probably serve, at least in the interim. Size is a pretty good hint about whether they are of similar capability. If the new one is about the same size or larger, it should be fine. It will withstand normal use since the voltage rating is well above the 50V threshold, however I'm not sure how it compares when it comes to ability to absorb spikes. Go easy on the transitions between forward and reverse, and it will at least get you going. You might consider ordering one for future installation.

    The tractor will run without it, but the life of the control relays and diodes suffers without it. Good luck, and I think it's a pretty cool wedding present!

    Nick
     
     

  6. Re: Replacement Varistor? 
    #6
    Junior Member
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    Thanks again! The Radio Shack one I have is slightly bigger diameter than the original. I'm guessing the ability to handle spikes is related to the 70 Joule energy rating. Unfortunately, I don't know what the rating on the original was.

    We thought it was a cool wedding present as well. Especialy since he just moved into a house with a Solar PV system that is 3 or 4 times the size of what he needs (he is extremely frugal in his energy usage).

    John
    Last edited by John Mc; 10-09-2014 at 12:48 PM.
    If the only tool you have is a hammer, you tend to see every problem as a nail. - Abraham Maslow
     
     

  7. Re: Replacement Varistor? 
    #7
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    Finland
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    I don't really see a way to PM you with this forum software that i'm familiar with, but the parts are in, it was $12.62 for the bearings and races sets, $.56 more if you want a pair of the square orings to help seal them from outside dirt. Shipping to Norway is $10 for 1st class and $26 for pri mail. Email me direct at game.tech.us att gmail dott com.
    We are the pioneers in providing JN0-102 exam toefl and Pass4sure 642-427 exams with 100% exam pass guarantee. Download our latest mines.edu and northwood or pass real exam of www.ku.edu
     
     

  8. Re: Replacement Varistor? 
    #8
    Junior Member
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    Champlain Valley area, Vermont
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    Pinkrosi - I think you replied to the wrong thread. This one was about Varistors. Was yours about the bearing upgrade for steering?
    If the only tool you have is a hammer, you tend to see every problem as a nail. - Abraham Maslow
     
     

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