Converting Monarch 10ee motor-generator 3-phase to single phase, Steelman method - Page 2
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  1. #21
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    I plan on using the original start-stop switches with the associated relay. I will need some education about "heaters". I suspect I will need different values for the heaters, know how to calculate the size and figure out where to get them. Any hints?

    As an aside, members may notice the new 8" x 12" x 2" junction box blocks access to the rear M-G grease zerks. I replaced the M-G and the Exciter bearings with sealed rather than shielded bearings and the grease zerks are no longer needed. If I live long enough for this to be an issue I'll shimmy up to this unit in my wheelchair, drag out the M-G and replace the bearings.
    Last edited by Flail; 01-13-2014 at 01:57 AM.

  2. #22
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    In order to size the heaters, it is necessary to have current readings for the run winding and the start winding. These will be different. A "clamp meter" is required.

    Alas, there is only room for two heater blocks, and the code (and good practice) requires the heaters to be placed after any capacitors.

    Also, you can add power factor correction to the run winding and reduce the amp draw, somewhat.

    What you have implemented, and have documented, a well-defined "skeleton" conversion which deserves to be "fleshed out" for operational convenience as well as for operational safety.

    I will be pleased to assist you in adapting the main contactor as your (M-G) controller.

  3. #23
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    Just to recap or set a 'marker'.

    Great thread, well-illustrated, good step-by-step, analysis, explanation of the details.

    From this, AND prior threads, major pluses:

    - at least when the Haas PF correction has been added to the Steelman conversion - is that the resulting combination delivers near-as-dammit 100% nameplate performance. That matches or beats best-case RPC, generally BEATS external static conversion schemes.

    - components required are similar or same as those required to DO a static or RPC. No significant 'premium' in total cost, possibly LOWER total cost.

    - modifying the existing MG also removes the need to source, purchase, transport, handle, and provide space for an external motor-as-idler.

    - end-product CAN also be used AS an RPC for other external loads when the 10EE is not in-use for turning.

    Downsides?

    - That the MG has to be removed and taken apart to implement the scheme.

    .. As even a decent USED VFD would probably cost more than the relay and capacitors, hard to think of any other downsides...

    Ergo, compared to materials costs and the freight or go-fetch to haul-home an idler motor, then still have to do all the OTHER construction and test?

    Clearly a slam-dunk in favour of this conversion.


    I have another machine that is nowhere near as flexible as a 10EE about how it is powered. This option may save me a great deal of grief.

    My thanks to all concerned in making that option both clear, and ..... (hopefully!..) ...adaptable to 3-P motors in general.

    Bill

  4. Likes neilho liked this post
  5. #24
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    Quote Originally Posted by Flail View Post
    ... In this box the upper left relay has a constant arcing across the contacts (while running the spindle in either forward or reverse). What is its function and it looks adjustable. What is the correct way to adjust it so it doesn't arc across the contacts which I presume it shouldn't?

    That's the FA (Field Acceleration) relay. Its job is to bypass the spindle motor field control potentiometer and apply full field to the spindle motor when the armature current is high, as when the motor is accelerating under load. It has one coil that's in series with the armature (to sense the armature current) and another coil that's just connected to 115VDC and appears to be used as a bias coil. I don't know at what armature current level the relay is supposed to operate.

    Is the relay cycling on and off, or what? Is it happening at low speed settings on the speed control?

    Do you have a meter with a 20A DC mode or a clamp-on ammeter that reads DC (most don't)?

    BTW, bravo on the work you've done and the nice way that you've documented it!

    Cal

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    Quote Originally Posted by Flail View Post
    Got the forward reverse thing sorted out. Headstock drum switch needed some adjustment. In this box the upper left relay has a constant arcing across the contacts (while running the spindle in either forward or reverse). What is its function and it looks adjustable. What is the correct way to adjust it so it doesn't arc across the contacts which I presume it shouldn't?

    The usual trick on a DC (not AC) load is to place a bit of capacitance across the contacts. As in the 'condenser' used on auto ignition distributor contact points for Donkey's years. And capacitors/condensers age and fail.

    BTW - compare components in your panel with this one from round-Dial MG 10EE S/N 17120, ordered December 1941, shipped September 1942.

    Note that not only are some of the components DIFFERENT, but they and others are not positioned in the same locations. Both of those affect how the wiring is run, inside AND on the back. I do not know if there were more varieties of MG 10EE or more varieties of panels. But it is something that wants more checking than assumptions.

    Bill

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    "end-product CAN also be used AS an RPC for other external loads when the 10EE is not in-use for turning"

    I'm not clear how this would be true.

    The three-terminal motor with 0-, 120- and 240-degree windings is turned into ... effectively ... a four-terminal (two terminals, net, to external equipment) motor with 0- and 90 degree windings.

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    Quote Originally Posted by peterh5322 View Post
    "end-product CAN also be used AS an RPC for other external loads when the 10EE is not in-use for turning"

    I'm not clear how this would be true.

    The three-terminal motor with 0-, 120- and 240-degree windings is turned into ... effectively ... a four-terminal (two terminals, net, to external equipment) motor with 0- and 90 degree windings.
    Earlier threads.

    - In one, that the windings can be brought out to an external box where their connections may be switched between Steelman-Haas and vanilla three-phase configuration. 'Switch' being the classical MIL gen set insulating 'board' with two different sets of holes, each strapped accordingly, not a house full of relays. Lines of 'n' Pole Double-Throw toggle-switches with an all-to-left, all-to-right configuration and a blocking rail or bar would also do. The current would neither be switched nor interrupted whilst 'live', just carried.

    - In another, a PM member who is using his MG - with 'conventional' static RPC components, IIRC - AS an idler for loads a 4 HP+ idler is suited to when the 10EE itself needeth not the DC output for its own use.

    Capacitor values and potential relay would be very similar to Steelman-Haas, no?

    Net, net, if/as/when one is going to delve into the innards of the MG to gain access to the windings so as to alter their connection ANYWAY...
    .. it would not be a terribly challenging extra step to bring them out individually to provide for the switching need.

    Overall, there would be very small 'extra' money in components, no significant extra mass, floor-space, noise, or transportation costs.

    Primary investment, IOW, is knowledge of prior art. And patience.

    Bill

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    Got it, thanks.

    I should have seen that one coming, as one of my points has always been that a Steelman-modified motor may be returned to a conventional motor.

    Peter

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    Quote Originally Posted by peterh5322 View Post
    Got it, thanks.

    I should have seen that one coming, as one of my points has always been that a Steelman-modified motor may be returned to a conventional motor.

    Peter
    You DID 'see it coming'.

    Your idea, not mine. I just retain trivia longer and try to make OTHERS make sumthin' out of it more often.. that 'synthesist' personality (AKA s***stirrer.) again



    Might add that it wouldn't add TOO much complication - two FW rectifiers @ $3/each, one DPDT MOM pushbutton, two relays - to have either of the MG's DC generator OR its exciter operate as 'pony' motors to bring EITHER the MG-as-RPC or MG-as-Steelman-Haas-W-L-drive-motor up to speed.

    Payback is no 'START' cap or 'potential' relay needed.

    Bill

  11. #30
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    So I'm thinking I can use the original 3-phase starter on my single phase conversion despite the fact the original starter only has two heaters. My logic is if I had a single phase motor, I'd really only need one heater as all the power is going to thru at least one heater and therefore two heaters on a single phase motor is redundant. In my schematic to follow, all the power goes thru relay contact L3 (1,7,12) which does not have a heater. A part of the power for the paralleled field (2,8) goes thru L1 which has a heater and a part of the power goes thru L2 which has a heater for the out of phase field (3). Thus the individual windings (fields) are protected. You will notice I eliminated the transformer as my light bulb in the on switch is rated 240 volts. Guess I'd rather keep similar voltages in the one conduit they go thru. Anyone see a potential error in this thinking?

    Last edited by Flail; 01-25-2014 at 06:18 PM. Reason: worse than usual wordification

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    Quote Originally Posted by Flail View Post
    Anyone see a potential error in this thinking?
    Wouldn't call it an 'error' so much as that having invested one Hellacious amount of tedious work so far, I'd want the best protection I could implement.

    That goal is probably better-served, now that you can actually measure the as-built 'normal' current on each leg individualy, by applying THREE thermal's, ganged so as to trip-out all on trip of any, but not (necessarily) all the same rating.

    They are not horribly costly, want 'proper' wiring, mounting, and enclosure, but that is not the same as 'original' as to location, etc.

    JM2CW

    Bill

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    Please review my original post, and the schematic diagrams attached thereto.

    In that post, I intentionally split the run winding across two starter contact sets, with the start winding through the remaining contact set.

    Then, in the "return" which is the combination of the two run windings, I place an overload, and the return for the start winding, I place the second overload.

    The returns necessarily must be connected before the starter, but after the fusible safety switch.

    This, then, will provide a motor controller with overloads in both the run and start windings, and a lock-out/tag-out capability for all.

    The Cutler-Hammer starter has overloads which are separate from the contactor, and these may indeed be wired as I have described.

  14. #33
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    Why are you switching the AC motor generator between forward and reverse? The dc lathe motor gets reversed through the control panel. Bob

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    Quote Originally Posted by vettebob View Post
    Why are you switching the AC motor generator between forward and reverse? The dc lathe motor gets reversed through the control panel. Bob
    I don't read the FWD-OFF-REV as having to do with the MG. Separate sections.

    Bill

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    Notice that the headstock's drum switch (same as the ELSR's microswitches) are implementing a "lockout" function.

    Namely, the FWD/Off-Brake/REV switch MUST be in the Off-Brake position in order to start the drive system. All 10EEs operate this way.

    IOW, the switch sections are N.O. if in FWD or REV and are N.C. if in Off-Brake.

  17. #36
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    I saw that after I looked at the drawing closer thanks. Bob

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    Recently got a 10EE turret lathe with a MG drive. Originally assumed it was functional, however it had been converted to a 180VDC controller.
    So I opened up the MG junction box and........... The godless savages had dyked off the leads. The external star point is still in place so I have been able to determine the 1,2,3,4,5 and 6 leads. Here's the problem: Once I have found the internal point for 10,11 and 12 (unlabelled I assume) how can I correlate those windings to my known ones. That is, how can I ensure that the two leads 7,10 are the correct winding to go with the 1,4 winding.

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    Default Determining field winding leads.

    Here is some more detail re: my question above.

    dsc01260-1-.jpg
    I am trying to determine the 7,8,9,10,11 and 12 points in this field coil. The 7,8 and 9 ends had been cut off, so I cannot tell which wires are 10,11 and 12. So I ripped into it....... and splayed out the six individual windings. The purple tabs are for the star point leads (10,11,12). The question for the motor experts is: Are the 7-10, 8-11, 9-12 windings across the diameter from 1-4, 2-5, 3-6 or are they adjacent to them? If Adjacent; are they clockwise or counter to their mating windings.
    I am going to replace all 12 leads, and would appreciate input as to the proper wire to use. I assume I can get the fibreglass sleeves and proper wire from my local motor repair guys?

    As always, thanks for everyones help.

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    My motor plate list the amperage as 13.2 for 230V operation. What would be the consensus suggested start and run capacitors? I have done some searching and see quite a number of conflicting values. Base on the formula I = 2 * π * F * C * V I arrive at 152uF that value is for the start cap under full load?

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    Quote Originally Posted by gernoff View Post
    My motor plate list the amperage as 13.2 for 230V operation. What would be the consensus suggested start and run capacitors? I have done some searching and see quite a number of conflicting values. Base on the formula I = 2 * π * F * C * V I arrive at 152uF that value is for the start cap under full load?
    It isn't that critical. I'd probably use 2 x 80 MFD 460 V ten dollah 'run' caps or 3 X 60 MFD 8 dollah ones ...if only because I have them on hand and there is no significant shortage of mounting space.

    Their ability to live long and prosper even if I was a tad lax as to disconnecting them when used for 'start' would be a freebie.

    Bill


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