Magnet/magneto energizer

Discussion in 'Electronics & Electrics' started by Matthew kane, Sep 29, 2020.

  1. Matthew kane

    Matthew kane Member

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    I have a few very old (1940-50’s) horseshoe type magnets removed from panel meter assemblies that has had its magnetic poles disrupted and therefore it has lost a lot of its magnetic field mojo.

    I don’t have all the necessary parts on hand to build a complete magneto or magnet charger/energizer.

    wondering if anybody here is willing to help me out?
     
  2. /invariance\

    /invariance\ Member

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    Considered re-energising the horseshoe magnets like this?
    Using a neodymium magnet from an old mech HDD and use the compass on your phone to determine the poles?
     
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  3. OP
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    Matthew kane

    Matthew kane Member

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    Not strong enough.
     
  4. Jonesy_sa

    Jonesy_sa Member

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    I had something similar magnetized years ago by an electrical motor specialist that rewinds and repairs motors.
    If you are happy to outsource you could try electrical motor repairers or give your local vintage car clubs a call (Austin 7/BMC etc) - they usually know the cheap places. We used a guy through the Austin 7 club when our magneto needed reenergizing.
     
  5. OP
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    Matthew kane

    Matthew kane Member

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    How big was the magnets? What I need remagnetised isn’t exactly huge in size or weight just needs to magnetised to the correct magnetic flux/field so it polarises correctly when dc is applied in 3 analog meter assemblies from the 30-40’s. This meter is part of a very sensitive circuit and its a test instrument.

    I’ve been looking at getting modern alternatives custom made which is using modern metal for magnetisation which should hold its magnetism longer than what I currently have.
     
  6. Jonesy_sa

    Jonesy_sa Member

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    We have had various sizes and shapes done roughly 30mm to 600mm diameter. Smaller were tiny engines and magnetos and industrial components the larger were always 3-phase industrial motors.
    We didn't request any specific flux/field requirements we just explained the purpose and they did the rest.
    sounds like something Carlsons Lab on YouTube would be right into!
     
  7. Jonesy_sa

    Jonesy_sa Member

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    How far have you got with this; is it easy to have them made? as in can you just provide the specs and a company will whip some up/
    I use to collect valve equipment, gov surplus phone communication hardware and test equipment. Purely aesthetics, I never restored, or even tested, any of it.
     
  8. OP
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    Matthew kane

    Matthew kane Member

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    I’ve just been browsing for local suppliers. It doesn’t even need to be in a horseshoe shape as long as the magnet field is approx right it’ll work.

    https://magnet.com.au/design-a-magnet.html not exactly cheap which explains why I’m still looking around. But I really do need a homebrew magneto charger. Easiest ones to make seems to evolve around using microwave trafo’s which I don’t have.

    The horseshoe magnet belongs in an AVO two panel tube tester.
     
  9. paulvk

    paulvk Member

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    Maybe just putting a neodymium magnet on the outside of the horseshoe might work.
     
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    Matthew kane

    Matthew kane Member

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    not powerful enough and have already tried.
     
  11. paulvk

    paulvk Member

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    Did you try one on each pole. With a big enough neodymium magnet you should be able to re-magnetize it by rubbing bunnings have a large one in a door close unit and jaycar has a rectangular one.
    Also found another bit of valve test gear and some valves.
     
  12. OP
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    Matthew kane

    Matthew kane Member

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    Ye already tried and no go.
     
  13. paulvk

    paulvk Member

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