3 phase induction motor for generator

Discussion in 'General Electronics Chat' started by Aleph(0), Oct 22, 2015.

  1. Aleph(0)

    Thread Starter Member

    Mar 14, 2015
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    I connect 9 lead 3 phase motor with capacitors for operate as generator. It works very well except load regulation sucks if av held constant for maintain 60hz frequency:( I using 5HP (which is 3.729kw) motor for Gen. To allow for inefficiencies I decide full load should be 2.5kw. When it's running at av for 60hz, unloaded voltage is 145v and loaded by 2.5kw voltage is 116v at single phase outputs. For now I follow with ferroresonant constant voltage xfmr but think there's better way? Tnx for help:)!
     
  2. Hypatia's Protege

    Distinguished Member

    Mar 1, 2015
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    That'd be the nature of the 'beast'!:cool:

    Well... You could implement two generators in a so called "dom/subby" arrangement -- howbeit I feel your approach of a FR transformer conditioned output is the best solution should a high degree of (effective) load regulation truly be required...

    What is your application for the described power-plant?

    Best regards
    HP:)
     
    Last edited: Oct 22, 2015
  3. GS3

    Senior Member

    Sep 21, 2007
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    Variable transformer?
     
  4. RRITESH KAKKAR

    Senior Member

    Jun 29, 2010
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    Hello,
    What is to be doe with 3 phase induction motor here?
     
  5. Hypatia's Protege

    Distinguished Member

    Mar 1, 2015
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    @Aleph(0)
    ---EMPHASIS ADDED---

    Your use of the plural suggests your arrangement may, in essence, be that illustrated below?
    IndGen2.jpg

    If so, you can do 'better' if you don't require a 3θ output --- Again, knowledge of your application would be quite helpful!:)

    Best regards
    HP

    PS -- I apologize that the above diagram is merely a screen capture of an 'off the cuff' design (rendered via LtSpice schematic editor) --- IOW, if anything fails to make sense - don't thump your head against the wall too hard -- it's probably my fault:eek::D
     
    Last edited: Oct 22, 2015
  6. #12

    Expert

    Nov 30, 2010
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    I have had good results with the ferro-resonant approach. Your 25% voltage deviation is within range for that method to be effective.
     
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  7. tcmtech

    Well-Known Member

    Nov 4, 2013
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    With those types of induction generator setups you can cheat your output voltages a bit by changing your capacitor values up or down to raise or lower the output voltage when at load.

    Still a limit to how far you can cheat though.
     
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  8. Hypatia's Protege

    Distinguished Member

    Mar 1, 2015
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    @Aleph(0) --- If you viewed post #5 prior to Ca. 9:10 PM CDT (22, Oct 2015) -- please have another look at the (presumptive) diagram of your circuit -- Apologies for my laxity and rather sloppy correction:oops:
     
    Last edited: Oct 22, 2015
  9. Aleph(0)

    Thread Starter Member

    Mar 14, 2015
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    HP Now you're saying ribald idiom all cuz too pc to say master/slave. I say you are product of your generation:rolleyes:

    Thanks but needs to be automatic cuz load constantly changing:)

    I want just to use motor as ac generator:)

    Thanks! Good to know I'm after accepted solution:)!

    Thanks! I use your suggestion to center mean voltage for #12's suggestion:)

    Now that think about it is exactly same with 20uf for the caps:)

    HP Plz show me exactly what you mean! Like you say I good student:)

    You say don't operate Tesla coil from mains cuz damage connected equipment and piss off Hydro big time:eek: So I build generator with 3 phase motor and drive with 40kw Rotec ULA engine. What I want Tesla for is psu for drt tube I can get to 2.5 megavolts before cost to rich for my blood:D
     
  10. GS3

    Senior Member

    Sep 21, 2007
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  11. RRITESH KAKKAR

    Senior Member

    Jun 29, 2010
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    Great!
    Any reason to generate electricity?
     
  12. Hypatia's Protege

    Distinguished Member

    Mar 1, 2015
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    You might be able to 'bring out' the common point of the 'inner coils' such that, in conjunction with the 'outer coils', you have three balanced 120-0-120 'circuits' - In addition to the 3Φ output -- Alternatively you may do anything you please with the outer coils (e.g. configure as 'delta' or neutral-accessible 'wye') while using the inner coils as a 3Φ circuit... --- That said your present configuration should be adequate for your application...

    Potential destruction of every electronic device connected to your secondary/secondary network (at least) - complete with the many lamentable corollaries thereof is probably worth avoiding --- IOW Correct!:eek:;)


    You may wish to reconsider use of a '2-stroke' engine in this application -- in any event you will want to avoid Rotec at all costs! Can we say 'cold seizure' -- Rotec is an inept designer/manufacturer of cheap, dangerous, toys -- granting that power loss does not pose a hazard in your application, I don't suppose there's any harm in using the engine until it 'breaks' -- Still...:rolleyes:

    While I 'relate' to your desire for a purly 'electronic solution' I'm bound to say you'll find rectifying the TC output a 'pain in the backside' to say the least -- even 'kennys' (i.e. Kenotrons) aren't much help above 1MV --- I trust you realize DRTs are not 'self rectifying'? --- Lowbrow though it may seem - your easiest course is VDG generator topology ---- Otherwise you're looking at lengthy (and, hence, lossy) full-wave CW cascades --- Well hey! Don't let me 'rain on your parade' if you know of a practical method of rectifying 2.5 MV @ ~200 kHz pray clue me in!:)

    All the best
    HP

    PS
    Actually I did not 'coin' the idiom in question -- 'tho I tend to believe you've identified the motivation back of its creation!:cool::D
     
    Last edited: Oct 23, 2015
  13. GS3

    Senior Member

    Sep 21, 2007
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    I believe it is for an electric chair for those who ask impertinent questions. Why else would anyone want to generate electricity for? :)
     
  14. Hypatia's Protege

    Distinguished Member

    Mar 1, 2015
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    Oh! I can vouch for Aleph - especially as she says it's for a Tesla Coil --- On the other hand a 'chair charger' could make for an interesting weekend project...

    [​IMG]

    But alas! 6 TOS 2 forbids!:(:cool:

    Crestfallen
    HP:D
     
  15. RRITESH KAKKAR

    Senior Member

    Jun 29, 2010
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    But how to Rotates the commutator or the the rotter?
     
  16. Aleph(0)

    Thread Starter Member

    Mar 14, 2015
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    HP I know they say that! But I am asking just what can go wrong? drt is just big hot cathode vacuum diode?

    HP Pic of execution chamber creepy cause so clean and bright and modern like exam room or classroom! Chair should be in moldy cellar or somewhere like that! I mean no matter how stand on capital punishment there's
    something cold bloodedly creepy when so damn civilized:eek:!

    Commutator for induction motor is just magnetic field:D! I use horse$h!t Rotec engine to turn rotor:)
     
  17. RRITESH KAKKAR

    Senior Member

    Jun 29, 2010
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    what is this?
     
  18. spinnaker

    AAC Fanatic!

    Oct 29, 2009
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    What do horses do after they eat?
     
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  19. RRITESH KAKKAR

    Senior Member

    Jun 29, 2010
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    from where and at what cost you buy it
     
  20. Hypatia's Protege

    Distinguished Member

    Mar 1, 2015
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    Succinctly: In normal operation the anode material coextensive with the 'focal spot' is sufficiently heated to exhibit thermionic emission, and, hence, issue of significant reverse currents leading to rapid destruction of the (relatively) 'delicate' cathode structure... The phenomenon is essentially high-vacuum 'cathode sputter' on steroids:eek: --- FWIW it seems kenotrons were available up to 5MV -- though I expect, owing to their scarcity, they'd cost more than the DRTs:rolleyes:

    Please understand, I know how frustrating it can be when a seeming 'collusion' of equipment design, material properties and economics seem to have you 'blocked at every turn' - moreover, it is not my intent to 'shoot down' your ideas! -- but, rather, to spare you vainly invested time and effort based upon my (often sad) experience... Again, my suggestion (RE: production of DC EMFs >1 MV) is implementation of an 'electrostatic machine' (e.g. a VDG or variant thereof) --- more 'elegant' solutions can come later:)

    All the best
    HP:)

    PS
    While your (above expressed) sentiment is neither uncommon nor unreasonable -- I offer the following:

    Things Aleph finds creepy:
    -Large bodies of fresh water...
    -(Allegedly) Secret Societies...
    -Well-appointed execution chambers...

    Did I miss anything?;):p:D
     
    Last edited: Oct 24, 2015
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