Help with circa 1905 AC motor wiring

Discussion in 'General Electronics Chat' started by Webnauseam, Jan 9, 2014.

  1. Webnauseam

    Thread Starter New Member

    Jan 9, 2014
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    Hello all. My first time here.

    I've got an old printing press that has a 110/220V AC motor. The name plate lists the following information:

    General Electric Single Phase A.C. Varying Speed Electric Motor
    Type: BSS546 4 1 1800
    Form: 03
    Voltage: 110/220
    RPM: 900/1800
    Number: 3756530
    Patents; Various dates, the latest of which was April 1905

    The motor includes a pedal rocker assembly attached by linkage to a cage of brushes surrounding a commutator that is part of the rotor. Operation the pedal moves the cage approximately 45 degrees of rotation around the commutator.

    Wires to the brushes have been disconnected by parties unknown.

    My initial research suggests that it is a "Repulsion" style motor. But troubling is that no mention of the word Repulsion is made on the name plate, and at least on all the on-line versions I've seen, GE lists 'Repulsion Motor" on the name plates. So I'm a little apprehensive assuming this to be a repulsion motor especially in light of the following:

    The brush cage assembly has 4 brushes two of which are hard wired into the stator housing. the two which are wired are 180 degrees opposed to one another, while the other two are side by side at approximately 60 degrees and 120 degrees relative to the other two.

    I could guess that this is a "Compensated" repulsion motor and the odd set of brushes are part of a compensating circuit, but I hate to make such assumptions. Especially since one of the wires to one of the brushes has separated, leaving a dangling end at each end, just begging to be rejoined togther.

    But, before risking anything foolish I thought it wiser to seek expert help, wondering if any of you might have access to schematic info for such a motor specifying how the correct connections need to be made?

    Further complicating this is that somewhere over the years someone has installed very out of place looking crimp-on spade terminal lugs to one of the non-wired brush assemblies( with no wires installed in the added lugs, however) making me wonder if the split wire was purposefully cut by someone intending to re route the wiring?

    My main intent here is to try and understand the box stock schematic the way it was originally intended to be, so that I can comfortably ignore whatever the intent was of this later modifier.

    thank in advance for any contextual help
     
    Last edited: Jan 9, 2014
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
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    It sounds like a brush riding type Repulsion motor where the brushes are engaged at all times and reverse is accomplished by positioning each side of neutral, and further movement is rpm control.
    I have an excerpt from the Rosenberg bible that details just about all the repulsion type motors.
    Max.
     
  3. Webnauseam

    Thread Starter New Member

    Jan 9, 2014
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    I'm a little perplexed over what the "latter day" modifier had in mind with the crimp -on connector. It truly looks as if it has no business even being there. But one has to wonder if it might just be a poor repair of a previously existing circuit, perhaps both loose wire ends are supposed to go into the crimp on connector, or perhaps the two loose wire ends were originally one wire (which would mirror the wiring to the brush that is 180 degrees opposed), and the added on crimp lug is just the madness of a modern day Frankenstine?
    \
    I'm reluctant to assume either way
     
  4. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Unless you are restoring this machine in order to retain its original form, it may be worth looking a modern alternative!
    Max.
     
  5. Webnauseam

    Thread Starter New Member

    Jan 9, 2014
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    There is an emotional value to restoring to original form.

    Since I last posted, I've spent some time cleaning the unit up, and now find the latest patent date being in 1918, not 1905 as earlier mentioned.

    Perhaps pictures might help?

    Here is a link to a picture of the motor. The drive pulley is on the far left, the control linkage is at the bottom, and the movable brush cage is towards the right end of the unit: (note the two wires coming out of the stator housing next to the red smudge mark. One proceeds down through a grommet, and attaches to a brush terminal, the other is loose, and just runs up toward the top of the image:

    http://i.imgur.com/Pk5dLqf.png




    Here is a link to a picture of the motor nameplate:

    http://imgur.com/6FNIQEa.png



    Here is a link to a rough sketch showing what I am working with. This is an end view from the brush end of the motor. The black dot being the center of the rotor. The light blue ring is the movable brush cage that rotates around the rotor, and each of the 6 brush terminals are shown as yellow dots labeled A thru F. The red links (A-C and E-F) are permanent connections from the factory. Coming from within the stator housing are the two wires labeled "W1" and "W2". W1 runs straight to terminal B, While W2 is not connected and is the source of this problem. I'm trying to figure out if W2 connects to W3 forming a complete circuit to terminal F, or if W2 runs to the crimp-on spade connector that sits freely on terminal D. (more discussion after the image) The violet stars depict connection points I am trying to determine

    http://imgur.com/JbGbbsN.png

    Of particular note, the intact circuit of W1 runs from the stator housing directly to terminal B. And terminal B is not connected (jumpered) to any other terminal. This makes me suspect that Terminal D might be the best destination for W2. But that introduces a whole nother problem of what then to do with W3?

    Hopefully one of you might have access to correct schematics, is my hope.



    One more picture just for the sake of completeness, a "top down" photo looking directly down onto the brush cage area, showing W1 coming out of the stator housing on the right hand side, W2 coming out of the stator housing just to the left of W1 (and hanging unconnected at it's far end) And Terminal D right in the center of it all, complete with unconnected spade connector:

    http://imgur.com/tk7kDiC.png


    Whew!! Hope I haven't put you to sleep with all this
     
    Last edited: Jan 11, 2014
  6. MaxHeadRoom

    Expert

    Jul 18, 2013
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    This a bit different to the repulsion motors I have come across before, never seen 6 brushes.
    Normally the input power only flows through the stator, on some there are stator coils connected to the armature through the brushes, called compensation windings, known as a compensated repulsion-induction motor.
    But they are not connected to the input power as yours seems to be?.

    I see there are terminal labels T1, T2 etc, I assume these are no longer there or no sign of them?
    You may have to do some more digging through the web and hopefully someone has a similar setup, that must qualify for one of the first types of repulsion motors made?
    It was generally replaced by Tesla's effort in the AC induction motor.
    Max.
     
  7. inwo

    Well-Known Member

    Nov 7, 2013
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    4 brushes or 6 ? 4 were mentioned. 6 pictured?
    All on commutator? ie. No slip rings?
    Do all brushes shift together?

    Only 1 stator winding?

    Are there signs that a transformer might be missing.
     
    Last edited: Jan 11, 2014
  8. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Normally there would not be a transformer.
    The brushes are usually connected in pairs to short or connect the armature windings like the winding bars on an induction motor would, If you lift the brushes on a repulsion motor, you can apply power and just twist the armature back and forth with no harm, as no rotor current flows, Unless the armature has a short, that is.
    Max.
     
  9. inwo

    Well-Known Member

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  10. MaxHeadRoom

    Expert

    Jul 18, 2013
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    The thing that I find confusing is that the supply power appears to be connected to the brush gear?
    Not a normal occurrence for any kind of repulsion motor, especially of that era.
    Max.
     
  11. inwo

    Well-Known Member

    Nov 7, 2013
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    Just checking, as some motor types in the GE link used an external transformer. Some used a second stator winding.

    None however used 6 brushes.

    I don't know why extra brushes would be needed for reversing, yet knowing that I don't know, led me to a guess. That fits the existing connections.:)
     
  12. Webnauseam

    Thread Starter New Member

    Jan 9, 2014
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    I posted "4 brushes" initially, in error. My bad, there are 6 all together. All six are fixed to this cage that encircles around the commutator, and the cage rotates around the commutator (only 45 degrees total travel) in the same way that a bracelet might be rotated around a wrist. The control linkage that rotates the cage is connected to a rocker-foot pedal such that the printing press operator could control the speed of the press by moving the pedal
     
  13. inwo

    Well-Known Member

    Nov 7, 2013
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    Thinking the same. Yet series/ parallel for 220/110 fits.
     
  14. inwo

    Well-Known Member

    Nov 7, 2013
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    It was clear in following posts.
    See what others think of my guess.
    Do you have a way of testing at reduced voltage? Variac.
     
  15. Webnauseam

    Thread Starter New Member

    Jan 9, 2014
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    "compensated repulsion motor" was what I suspect as well, but the presence of 6 brushes has me scratching my head. I have yet to put power on this, as I'm trying to understand the design before risking anything I might regret.

    The T-Terminals are in the power feed junction box, and the diagram just shows how to make the connections depending upon if the supply voltage is 110V or 220V
     
  16. Webnauseam

    Thread Starter New Member

    Jan 9, 2014
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    That's an excellent suggestion that I had not thought of.

    Thus far all I've done is to meg it out, making sure nothing has gone to ground.

    I'm reading about 220 ohms between any two sets of brushes, and they are all "clear" from ground
     
  17. inwo

    Well-Known Member

    Nov 7, 2013
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    Didn't notice other connections.

    Is there more than one stator winding?
    How do the T1-T* connect to your other drawing.

    If no variac, at least test on 120 using the 220 diagram. It should run fine.

    Well back to the drawing board.:(
     
  18. inwo

    Well-Known Member

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    Am I missing it, or is no direction information given?
     
  19. Webnauseam

    Thread Starter New Member

    Jan 9, 2014
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    Reference this picture:

    http://i.imgur.com/Pk5dLqf.png

    Notice the flexible metal conduit at top of image. The flex running up to the left is "line in". The flex running to the right and down just loops to an "on/off" switch mounted on the front of the press unit..

    The T Terminals I expect are in the junction box that both tap into, on the lower side of the motor.

    As far as the point of origin for W1 and W2 in the sketch, they originate inside the motor housing, exactly how I am not yet sure of. Haven't had the main case open yet. I just figured they must originate at the stator, somehow.
     
  20. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Normally the stator windings are series/parallel for dual voltage versions, the armature stays the same.
    The reversing is usually done by the brush gear movement.
    I have yet to find a repulsion motor where the armature is connected to the power input supply.
    Max.
     
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