'Muscular' Synchros...

Discussion in 'General Electronics Chat' started by Hypatia's Protege, May 20, 2016.

  1. Hypatia's Protege

    Thread Starter Distinguished Member

    Mar 1, 2015
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    Kind friends

    The following question arose on another (rather obscure) thread -- Inasmuch as I find the subject of the inquiry to be both intriguing and, likely, of broader interest - I thought to re-post it here:

    Note: The above alludes to the common 1Φ rotor/3Φ stator arrangement (à la the GE 2J1G1 and it's ilk).

    FWIW - My thought is that difficulty, if manifest, will owe to disparity in rotor winding patterns -- Any thoughts/insight will be greatly appreciated!:)

    Best regards
    HP
     
  2. Kermit2

    AAC Fanatic!

    Feb 5, 2010
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    It would most likely work but would not be an efficient motor. Magnetize the rotor and create a rotating field in the stator is all you need, but the design is for generating and not motoring.
    I would think it should be quite a robust motor, just not frugal with the amps.
     
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  3. MaxHeadRoom

    Expert

    Jul 18, 2013
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    That would be very close to the type of synchronous motor of the past that were up to the 100hp range, the motor was essentially a induction motor with the addition of a rotor winding with two slip rings, the motor was ran up as a standard induction motor and the slip frequency was monitored via the slip rings, when the slip freq reached around 5 cycles, DC was injected into the armature and the motor came up to synchronism.
    I don't see why a standard alternator would not run as a synchronous motor?
    Max.
     
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  4. Hypatia's Protege

    Thread Starter Distinguished Member

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    First of all thanks for your replies!:)

    I apologize that there seems to be some misunderstanding...
    Based upon her (@Aleph(0) 's) use of the term 'Selsyn' I take it that the question relates to the functionality of automotive alternators as Synchros -- As opposed to synchronous motors...

    FWIW, here's another link to a discussion of said devices (found in AAC's 'text book' section):)

    Again, many thanks for these and any future replies -- apologies for the ambiguity:oops:...

    Very best regards
    HP:)
     
  5. nsaspook

    AAC Fanatic!

    Aug 27, 2009
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    As per the AAC article direct powered synchros are usually limited to low power by the lack of efficiency in converting electrical power to torque. The phases create a positional 'null' by the subtraction/addition of fields that require a high ratio of steady power/response power to maintain on position.
    http://www.maritime.org/doc/neets/mod15.pdf
    http://www.maritime.org/doc/pdf/synchros.pdf
    Note Page 44

    I worked on the old BB-61 class ships in the 80's while they were being recommissioned. Almost all the original gun systems used a synchro control transformer and Amplidyne for actual movements with synchro transmitter inputs from the master gyro compass to correct for pitch, roll and yaw.


    [​IMG]
     
    Last edited: May 21, 2016
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  6. Aleph(0)

    Member

    Mar 14, 2015
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    HP thanks and THANKS TO EVERYONE:)!

    Ok so I tried it and it sorta works but cuz of six pole rotor it's lame:( I have to turn it real slowly or it can jump 60 degrees to the next sync point:mad: I say it is cool that it transmits 80 foot pounds of torque though:cool:! (Sorry cuz I don't have a metric torque wrench). I say maybe it would work better at different frequency and voltage cuz I'm using 90v peak 60hz sine wave for rotor excitation. So anyhow I'm thinking about transforming it so I can get _advantage_ one to the other:cool: So it would convert low torque to high torque one way but the other way it's hard to understand what high torque to low torque means when there's no change in angular velocity so power is lost but not just dissipated:confused: So if anyone is saying I have too much time on my hands I say it's most fun I've had without a hangover and remorse;)!
     
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  7. Hypatia's Protege

    Thread Starter Distinguished Member

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    I believe you'll find that it is excessive acceleration (as opposed to AV) that produces the described undesirable operation...

    I agree!:cool:

    The greatest frequency consistent with acceptable hysteresis losses will produce the greatest torque -- Of course 'the rub', as it were, lies in the adjective 'acceptable' --- For all that, I assert that the described system will produce significantly better results at higher frequencies (Somewhere between 200 Hz and 600 Hz):) --- The optimal EMF is, of course, a function of frequency...

    IMNSHO Amplification makes more sense than 'transformation' in this context -- Moreover, I daresay you will find musings upon 'compliance' with (physical) conservation law less frustrating following formation of a definite scheme;):)

    Hold that thought!:cool::cool::cool::cool::cool::cool:

    All the best
    HP:)
     
  8. Jazz2C

    Member

    May 27, 2016
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    Maybe she wants it to stay bidirectional? That way the reciver reflects some of the feel of the load back to the transmitter. I know steering systems for some mechanized armored military vehicles used that principle. HP I'm concerned! Plz shoot me an E.
     
  9. Hypatia's Protege

    Thread Starter Distinguished Member

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    I hear ya! It may well be for her heuristic aircraft project{s} -- Speaking for myself, I'd want plenty of 'redundancy' - Well in excess of regulatory requirements -- Vehicles are just plain safer when under control;):D

    If you have something to say to me - please say it here:cool: -- OTOH, If you fear it would be deleted then perhaps it should remain unsaid:rolleyes:

    Best regards
    HP:)

    PS -- Hey, @Aleph(0) -- How about it?:cool:
     
  10. Jazz2C

    Member

    May 27, 2016
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    I worry that she's on track to avoid old age! I mean I don't doubt her engineering skill but test piloting experimental aircraft is riding for a fall, literally!:(

    I don't know what's deleteable or not but it's not offensive. But I'll take the hint and suffer in silence:(
     
    Last edited by a moderator: May 28, 2016
  11. Hypatia's Protege

    Thread Starter Distinguished Member

    Mar 1, 2015
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    I hope you survive! -- I'm humbled by your courage!;););)

    TTFN
    HP