Microwave inverter into power supply

Discussion in 'General Electronics Chat' started by Gabriell, Jan 16, 2016.

  1. Gabriell

    Thread Starter Member

    Jan 16, 2016
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    I pulled out a microwave oven inverter today and i was wondering if i could make it into a power supply just like the older microwave oven transformers.

    Can i rewire the secondary just like the big old ones? any tips how could i turn it into a 120v power supply?

    Thanks
     
  2. Gabriell

    Thread Starter Member

    Jan 16, 2016
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    4
    IMG_2299.JPG IMG_2300.JPG IMG_2301.JPG
    Maybe this image will help. Not many reply's so far...
    I tried to connect it 240v but it just blow my fuse.
    Internet search doesn't give much on these things. Anyone familiar with these things??????
     
  3. Hypatia's Protege

    Distinguished Member

    Mar 1, 2015
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    A 12V DC to 120V 60 Hz inverter is best realized via 'double conversion' topology -- Although a MOT inverter transformer may be used in the first stage of such a scheme, IMO such is not practical in consideration of the amount of rewinding required -- That said, MOT inverters are excellently applied to LVDC → HVDC conversion where space/weight economy are desirable (e.g. the plate [i.e. anode] supply in tube operated mobile communication equipment) :):):)

    Best regards and have fun!:)
    HP
     
  4. Hypatia's Protege

    Distinguished Member

    Mar 1, 2015
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    @Gabriell
    ...On the other hand, If you merely want a DC PSU you may 'unwind' the secondary to such extent that the EMF is 'in range of' your proposed rectification/regulation scheme... Note that the operation/output frequency (tens of kHz) is significantly easier to filter than 60hZ!:cool:

    Best regards
    HP
     
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  5. Gabriell

    Thread Starter Member

    Jan 16, 2016
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    Thank you for your message!
    I wish i would understand what you are trying to say but im lost. :(
    The inverter runs on DC instead of AC?
     
  6. Gabriell

    Thread Starter Member

    Jan 16, 2016
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    So if i rewind the secondary and apply dc voltage to the primary it should be ok?
     
  7. Hypatia's Protege

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    No, direct application of DC to the primary won't work! -- Just use the supplied driver!:)

    Best regards
    HP
     
  8. Hypatia's Protege

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    Mar 1, 2015
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    The inverter proper operates on DC derived from rectification of mains current -- howbeit, the unit as a whole is essentially a 60HZ mains 'voltage' to high 'voltage' DC converter.....
     
    Last edited: Jan 17, 2016
  9. Hypatia's Protege

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    Mar 1, 2015
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    So... If you want a lower 'voltage' DC power supply -- You need only modify the secondary (and, perhaps, the secondary circuit) for the desired output -- then power the unit from the mains (as it was connected in the microwave oven)...:)

    Best regards
    HP
     
  10. Gabriell

    Thread Starter Member

    Jan 16, 2016
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    Unfortunately i dont have circuit anymore. I will try to salvage another one.

    So i cant just unwind the secondary and apply AC and then connect it to a bridge rectifier?
     
  11. Hypatia's Protege

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    Mar 1, 2015
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    Unfortunately the magnetic properties of ferrite preclude said application at low frequencies (CIP 60Hz) -- that said, you may be able to build a simple driver (of, for instance, resonant Royer/"ZVS" topology)... Can you run a continuity test on the transformer and post the results?

    Best regards
    HP
     
    Last edited: Jan 17, 2016
  12. Gabriell

    Thread Starter Member

    Jan 16, 2016
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    Hmmm probably is should have told you first that im not an electrician and my knowledge is very limited. I have no idea how to do a continuity test and i dont know what " resonant Royer/"ZVS" topology" means...
    But i appreciate your help!!!
     
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  13. Hypatia's Protege

    Distinguished Member

    Mar 1, 2015
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    Ok I hear you! - No problem:) -- I think your best move is to salvage another inverter -- Don't remove the transformer unless necessary to access the secondary --- when ready please let me know, and I'll be happy to 'walk you through' the modification!:cool:

    Best regards
    HP:)

    PS -- Many microwave ovens equipped with conventional MOTs are still 'floating around' --- Should you go that route, please try to find an older unit inasmuch newer MOTs tend to have small cores and, hence, rather low saturation thresholds...
    Also - Please hold on to your present inverter transformer! -- Someday you'll be glad you did!:):):)


    Very best regards
    HP
     
  14. Gabriell

    Thread Starter Member

    Jan 16, 2016
    47
    4
    Great thank you! I will get back to you soon!
     
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  15. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    No. You can't just apply mains frequency power to it. Those transformers need to be driven at many kHz.
     
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