10EE with solid state DC drive - how to add reverse circuit and ELSR
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    Default 10EE with solid state DC drive - how to add reverse circuit and ELSR

    I'm hoping someone out there in 10EE land can assist in giving me some advice on solid state DC drives.

    I recently bought a 1949 Monarch 10EE. The lathe was originally built with the Reliance 3 hp, open-frame motor and the motor-generator.

    At some point, the generator must have been damaged and an aftermarket, single phase, DC solid state drive was installed. The drive is housed in one large Hoffman enclosure and a second enclosure houses the start / stop buttons and THE largest rheostat I have ever seen.

    The spindle can only be turned on for forward motion or stopped and its speed is controlled by the large rheostat. There is no electrical cut-off or e-stop.

    The lathe is equipped with the ELSR option and a 3ph coolant pump, but neither is wired for use. I pulled out the original motor generator and it looks like the generator sustained some damage to the armature at some point.

    It looks like the DC drive was installed by Weaver Electric in Denver, but I do not know if they made their own drive or used one from some unknown supplier and installed it in a Hoffman box. I plan on calling them tomorrow, but I doubt it will be much help...the drive looks old and they don't mention anything like it on their website.

    Anyway, the motor / drive operate well and I can vary the speed from low to 2400 rpm without any issues. When I push start, the motor starts winding up, there are two timers on the drive board and the first one goes off after a couple seconds and closes contactor AR-1. After about 10 seconds, timer two goes off and closes contactor AR-2. I really don't hear a difference in the speed or sound of the motor. It does operate very quietly.

    What I would like to do is add the circuitry to allow running in reverse and at some point, wire the ELSR to operate. I was also thinking about at least mounting the large rheostat near the factory location and have the factory designed speed knob. The original rheostats are present, but the large rheostat is more than double the factory Monarch unit at 950 ohms. It does look like there is some sort of high amp voltage divider on the drive board and I wonder if it can be adjusted to the lower resistance of the factory rheostat.

    Attached are photos of the motor, board, and control box.

    Wiring to the drive is pretty simple with only line voltage at L1 and L2 (240 VAC), Stop (NC) at C1, C2 is common to the stop/start switches, C3 is the Start switch (NO), A1 and A2 to the motor armature, R1 is from the rheostat, F1 is not connected on the board but is connected to the wiper side of the rheostat and wired directly to the motor's F1, and F2 goes to the motor F2 field.

    Any help is appreciated.
    Attached Thumbnails Attached Thumbnails motor-drive3.jpg   motor-drive.jpg   drive-board.jpg   reostat-box.jpg   reostat-back.jpg  


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    Quote Originally Posted by jj80909 View Post
    I'm hoping someone out there in 10EE land can assist in giving me some advice on solid state DC drives.

    I recently bought a 1949 Monarch 10EE. The lathe was originally built with the Reliance 3 hp, open-frame motor and the motor-generator.

    At some point, the generator must have been damaged and an aftermarket, single phase, DC solid state drive was installed. The drive is housed in one large Hoffman enclosure and a second enclosure houses the start / stop buttons and THE largest rheostat I have ever seen.

    The spindle can only be turned on for forward motion or stopped and its speed is controlled by the large rheostat. There is no electrical cut-off or e-stop.

    The lathe is equipped with the ELSR option and a 3ph coolant pump, but neither is wired for use. I pulled out the original motor generator and it looks like the generator sustained some damage to the armature at some point.

    It looks like the DC drive was installed by Weaver Electric in Denver, but I do not know if they made their own drive or used one from some unknown supplier and installed it in a Hoffman box. I plan on calling them tomorrow, but I doubt it will be much help...the drive looks old and they don't mention anything like it on their website.

    Anyway, the motor / drive operate well and I can vary the speed from low to 2400 rpm without any issues. When I push start, the motor starts winding up, there are two timers on the drive board and the first one goes off after a couple seconds and closes contactor AR-1. After about 10 seconds, timer two goes off and closes contactor AR-2. I really don't hear a difference in the speed or sound of the motor. It does operate very quietly.

    What I would like to do is add the circuitry to allow running in reverse and at some point, wire the ELSR to operate. I was also thinking about at least mounting the large rheostat near the factory location and have the factory designed speed knob. The original rheostats are present, but the large rheostat is more than double the factory Monarch unit at 950 ohms. It does look like there is some sort of high amp voltage divider on the drive board and I wonder if it can be adjusted to the lower resistance of the factory rheostat.

    Attached are photos of the motor, board, and control box.

    Wiring to the drive is pretty simple with only line voltage at L1 and L2 (240 VAC), Stop (NC) at C1, C2 is common to the stop/start switches, C3 is the Start switch (NO), A1 and A2 to the motor armature, R1 is from the rheostat, F1 is not connected on the board but is connected to the wiper side of the rheostat and wired directly to the motor's F1, and F2 goes to the motor F2 field.

    Any help is appreciated.
    It may work just fine, but I cannot "visually match" that to any recent, volume-production, commercial DC drive, and I have manuals for "many".

    It appears to be a First-Quadrant, contactor-reversing, 4 SCR-only implementation, shop-fabbed.
    Also a bit of a kludge, "work just fine" or otherwise. That "large rheostat" resembles a selector switch for an array of discrete resistors I once encountered in some other fossilized device.



    "Records retention" policy may have sent any documentation Weaver ONCE had off to archives or recycled paper by now. If you or Weaver have no manual or schematics, it would be wise to reverse-engineer it and create such to be assured of doing no harm whilst integrating the ELSR to its control inputs, and for future maintenance, fault isolation and analysis.

    That is not at all hard, devices as simple as this one appears to be.

    OTOH, ELSR effectiveness cannot be assured just yet.

    This rig retained braking resistors that a 4Q drive needeth not, but I've no idea how well, how quickly, nor how repeatably it brakes compared to the OEM drives and THEIR braking resistor effectiveness the ELSR originally worked with. It could be better, about the same, or quite a bit LESS effective.

    Personally, I'd aside it and replace with a majority-maker 4Q DC Drive still in volume production, to wit, the Eurotherm/Parker-SSD 514C-16 already in-use by several among us. Those have very comprehensive manuals, and they are online.

    everetteengr DID integrate his ELSR controls to his one, the thread on PM covers all that.
    AFAIK, you'd use the same control input approach as he used for his SSD drive.

    The major diference is that his one IS a"4Q" drive, so stops are fast, predictable, and adjustable, braking resistors or power contactors neither used, nor wanted.

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    You see rheostats on things like ancient centrifuges. Not the original Monarch. This is an illustration of why some of us tell people to keep the original drive if possible. You may get the spindle to turn but lose the nuances. All those relays on the panel are not there for looks. Besides a four quadrant drive, which may be the best solution now, you will also need a variable field supply because the upper speed range is achieved by reducing the field voltage. For dynamic braking you need to switch the field to full voltage and shut it off after a few seconds. I don't know about the MG machines with the big motor, which BTW is a very smooth motor and should be retained if possible, but the timer failed on a tube type 10EE and the head would get so hot from motor heat that you couldn't hold a hand on it. Of course, that was in a large shop where various people used the lathe and some would leave the main power on overnight, cooking the motor.

    If you have the original relay panel, you can use the contactors for reversing, but you need to be sure the anti-plugging relay is functional.

    My suggestion is that you get the factory manual from Monarch. They will sell you a manual customized for your serial number. Even if the functions are gone, you can read about them and consider implementing them in the new setup. As the saying goes, you have your work cut out for you.

    Bill

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    If he's getting 2400rpm then field weakening must be in operation.

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    Quote Originally Posted by Peter. View Post
    If he's getting 2400rpm then field weakening must be in operation.
    Soitenly! We just don't yet have a klew how well regulated, or even IF.

    Doesn't look like enough parts-count to have implemented a Field Regulator where Armature control is made the slave to it, rather than primo RPM setter - but it COULD have.

    Most DC lift motors came to utilize those as buildings grew taller and "express" response speeds more important.

    This rig looks WEIRD and "orphan-class" as to maintainability, but it might make chips just fine.

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    Quote Originally Posted by Peter. View Post
    If he's getting 2400rpm then field weakening must be in operation.
    Depends on the pulleys. What speed does the tach go up to?

    Bill

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    It does run from low speed all the way to 2400 rpm (read from the stock mechanical tach). The lathe has the original motor, back-gear box and pulleys. The knob for the big rheostat does have two arrows on it: "increase voltage" and "increase speed" and it is wired into the field circuit. The lathe was used with the present, "forward only" configuration for the last 20+ years...I'm guessing that's reliable enough

    For now, I think I'm going to create a circuit with two timers and contactors like the one I found with a Google search. I don't foresee needing to change from forward to reverse all that quick. The ELSR would be handy for threading so I'd like to wire its micro switches to control the spindle.

    The lathe came with a nice 5C setup and I plan to use it for prototype work. I don't see the lathe being used to take heavy cuts and it would be nice if it was the 4000 rpm model.

    In the future, I think I'll go with a VFD and large, modern motor. From what I've read, the spindle is essentially the same on the 2500 rpm and 4000 rpm models. If I find a stock 4000 rpm tach, is it a simple swap?

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    Forward / reverse circuit
    Attached Thumbnails Attached Thumbnails fr-circuit.jpg  

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    Quote Originally Posted by jj80909 View Post
    Forward / reverse circuit
    Given you are not reversing "often" and probably not in extreme haste, it would be simpler to put a DPDT switch (or relay) in the Field Power supply line and "Field-Reverse" the motor instead of Armature-Reversing it.

    There is only about 1500 mA @ 115 VDC to deal with.

    The reason it is not done more commonly is that the Field Coils and the laminations have a good deal of "inertia" for that relatively small power.

    There are "white papers" out there covering trick circuitry for over-driving the field supply - but only briefly - on each reversal to speed up the response. I don't think you would need any such speed-up - just passive spike snubbing, if even that.

    Fast enough and cheap enough to find out, yah? Switch, consumable MOV's mebbe a bypass cap and fuses "just in case". See what the 'scope tells you. Back it down to simple-dumb.

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    Quote Originally Posted by thermite View Post
    Given you are not reversing "often" and probably not in extreme haste, it would be simpler to put a DPDT switch (or relay) in the Field Power supply line and "Field-Reverse" the motor instead of Armature-Reversing it.

    There is only about 1500 mA @ 115 VDC to deal with.

    The reason it is not done more commonly is that the Field Coils and the laminations have a good deal of "inertia" for that relatively small power.

    There are "white papers" out there covering trick circuitry for over-driving the field supply - but only briefly - on each reversal to speed up the response. I don't think you would need any such speed-up - just passive spike snubbing, if even that.

    Fast enough and cheap enough to find out, yah? Switch, consumable MOV's mebbe a bypass cap and fuses "just in case". See what the 'scope tells you. Back it down to simple-dumb.
    Uh uh. Reversing the shunt field makes the series fields work the wrong way and the motor does weird things. Only flip the brush leads.

    Bill

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    Quote Originally Posted by 9100 View Post
    Uh uh. Reversing the shunt field makes the series fields work the wrong way and the motor does weird things. Only flip the brush leads.

    Bill
    "Flipping" Armature leads wants far higher rated contacts than field needs. One full order of magnitude so, almost exactly.

    Annnnnd they are in the circuit of not-as-rugged-as-we-might-wish-they-were SCR's.

    On the "special machine tool duty" GE KinaMatic 5HP (no gots), the Louis-Allis 5HP (no gots), the Reliance small-frame 3 HP (do have), and the rare Reliance 5 HP (too expensive for MMT to keep buying - my one is a non-MMT RPM III), with either/both of compensating or compounding, YES, there is an issue.

    Predictable, not weird. Also "tolerable".

    Feedback is bass-ackwards, increasing load worsens RPM drop instead of helping offset it. Even so, it hasn't been a show-stopper for typical USE when in reverse.

    AFAIK, the large-frame 3 HP is classical "pure" shunt, and has no such winding issues. Life of me I can't remember why I never put it to the test, what with all the other testing I did.

    I DID test the small-frame 3 HP Reliance, and it was "acceptable" with field-reversing. That was because it would have had to have the S1, S2 leads that are seriesed with the Armature rearranged at the armature connections IN ANY CASE to behave itself better even when Armature-reversed. With a 4Q drive, one just tapes those off, unused.

    Could test a large-frame 3 HP. One of the three here is not down for rebuild.



    What with 4Q drives, I've no need.

    Faster if the OP checks it out on his one.

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    Think the best way to do this is follow Monarch's example and install interlocking contactors and reverse polarity on the armature. Considering you don't have prints for the drive, it's asking a lot to sort this out over a forum, might be a good idea to get a pro involved.

    Bill-with a 4Q drive, why did you not install a bridge rectifier ala monarch drive and make advantage of the "designed in" characteristics of the motor and the enhanced speed regulation from having S1/S2 connected?

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    Quote Originally Posted by Colt45 View Post
    Think the best way to do this is follow Monarch's example and install interlocking contactors and reverse polarity on the armature. Considering you don't have prints for the drive, it's asking a lot to sort this out over a forum, might be a good idea to get a pro involved.
    Keep up in back. There ARE "pros" involved.

    Mechanical contactors need serious attention to detail lest they destroy his fragile SCR's.

    As D510's have done. Repaired one pro bono commune myself.

    Hence the preference for 4Q drives, whether over-run control is needed or not. Sync is inherent. No arcy-sparky. ZERO NEED of mechanicals. Not just me. Industry wide. And since forever-ago. Even ignorant contactor-contactors use a lot of SSR's instead of mechanicals.

    Bill-with a 4Q drive, why did you not install a bridge rectifier ala monarch drive and make advantage of the "designed in" characteristics of the motor and the enhanced speed regulation from having S1/S2 connected?
    Because there is no gain for the extra work and complexity on the 5 HP.

    The "nominal" 3 HP large-frame has no such need. It is actually a 4.6 HP where I run mine, and I prefer its greater low-end torque to the 5 HP anyway. HSS-Cobalt guy. My carbides eat wood, not metal.

    Solid State DC drives can "IR" regulate to waaay better that actual need on the 10EE, and borderline insane finesse if given a tachogenerator.

    All of which is useless without a Field Regulator anyway. 10EE's range is more in Field Weakened zone than not.

    The PREDECESSOR to the 514C had that option. The Field Regulator was separate hardware and about triple the cube of the SSD drive itself. Armature control is slaved to Field, current-loop mode, not the other way 'round, and they regulate really, really well

    The 3-Phase-input ONLY modern Parker (most others as well) drives have it too. Either on-PCB or as a slot-in option to a mainboard PCB.

    Jonathan Esar's late Dad even included the traces for a Field Regulator on the mainboard of what became the Beel/BICL D510. And that one is a 1Q drive, contactor-reversed. That section (nor the tacho feedback section) just are not "populated" as-built on his drives.

    The affordable one-phase-in DC drives otherwise a good fit (Eurotherm/Parker-SSD) do NOT have inherent provision for Field Regulation.

    SO far, it has simply been "good enough" for my use to NOT gang Armature and Field controls.

    Much like flying an aircraft with constant-speed prop, one just adjusts, manually.

    That was a nuisance in a 172 RG vs a PA-28, but BFD, It worked OK. I just never liked Cessna's. (Sorry, Bill, NOT EVEN with round-engines, though they were far the better aircraft!! A neighbours Stinson Reliant OTOH.. Like a DHC2 with actual comfort !!!).


    If I run out of things to play with, I may at some point do a 3-Phase-only DC drive and bypass those limitations. Easy-peasy with several of those - no work to do.

    The problem is that "ordinary" DC motors of the class 10EE used are but a backwater these days. DC, hybrid, and servo technology has moved-on. AC has gone dirt-cheap, and good enough for many folks.

    That has left too-few players in the market who support the single-phase-input-only DC Drive needs at the voltages a 10EE uses. Most are 180 VDC, max, players.

    Lazy, Iyam, so all the OTHER DC motors under-roof are 180 VDC wound Reliance RPM III.
    At 180 VDC KB-Penta drives are good enough! Especially as I don't Field-Weaken them anyway.


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    Bill-no doubt that a modern 4Q/regenerative drive is a great solution, but he's asking about how to add a reverse function to his "existing" drive, not install a completely new drive. When I mentioned getting a pro involved, I meant someone on site.

    Monarch went to some trouble and expense in choosing those particular motor designs, it's neither difficult nor expensive to make use of their inherent performance advantages. Can be done with off the shelf components and simple connections.

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    Quote Originally Posted by Colt45 View Post
    Bill-no doubt that a modern 4Q/regenerative drive is a great solution, but he's asking about how to add a reverse function to his "existing" drive, not install a completely new drive. When I mentioned getting a pro involved, I meant someone on site.

    Monarch went to some trouble and expense in choosing those particular motor designs, it's neither difficult nor expensive to make use of their inherent performance advantages. Can be done with off the shelf components and simple connections.
    They WERE performance advantages for the available technology. Technology kept moving.

    Yes, the DC motors are worth retaining. NEW Reliance (Baldor/ABB) 5 HP Dee Cee are around twelve thousand USD EACH! They still add value. That is not the same as "sacred gods".

    Do keep in mind that Monarch Machine Tool had made a business decision to cease production of lathes OF ANY KIND and motored-off to Cortland NY to try drill presses well before current drive technology was even close to affordable.

    IF EVEN it existed at all outside of NASA or DoD contracts.

    We don't HAVE to roll the clock back to the best Monarch Machine Tool could afford back in the day. Monarch Lathes does not. They use AC 3P + an industrial-grade VFD.

    We ALSO have better choices, and less-costly ones, long-since. DC or AC.

    Those choices are easier to exercise now.

    A VFD, for example, is orders of magnitude more complex than an "analog" DC drive.

    In both cases, we don't have to give a s**t about their internal complexity because we are NOT going to fab either/any of op amps, SCR's, Bipolar IGFET transistors, nor certainly a CPU or PLA "in the Silicon".

    They are packaged "black box" appliances we simply replace.

    A packaged major-maker DC Drive with manual, or a conversion to packaged major-maker VFD with manual may be CHEAPER for him that running a minority-maker, one-off, that has no manuals.

    It comes down to whether one wants to play with motor and drive technology... or make chips.

    I don't have to make chips. The OP may have to.

    Up to the OP which part of which risk-set he is comfortable with.

    After all - he can ALWAYS make another choice, later.

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    Quote Originally Posted by thermite View Post

    On the "special machine tool duty" GE KinaMatic 5HP (no gots), the Louis-Allis 5HP (no gots), the Reliance small-frame 3 HP (do have), and the rare Reliance 5 HP (too expensive for MMT to keep buying - my one is a non-MMT RPM III), with either/both of compensating or compounding, YES, there is an issue.

    Predictable, not weird. Also "tolerable".

    Feedback is bass-ackwards, increasing load worsens RPM drop instead of helping offset it. Even so, it hasn't been a show-stopper for typical USE when in reverse.

    AFAIK, the large-frame 3 HP is classical "pure" shunt, and has no such winding issues. Life of me I can't remember why I never put it to the test, what with all the other testing I did.
    Behavior depends on the balance between the shunt and series fields. It can run away to the point that the armature is trying to go infinitely fast and drawing very high current.

    My motor has series poles but they are interpoles, not compound fields. My Monarch manual doesn't even show them but they are there. There is too much junk in the way where the lathe sits right now to trace the wiring to see if the interpoles are reversed. In any case, it wouldn't have severe effects in operation. Interpoles are mainly to reduce brush arcing.

    Bill

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    Quote Originally Posted by 9100 View Post
    Behavior depends on the balance between the shunt and series fields. It can run away to the point that the armature is trying to go infinitely fast and drawing very high current.

    My motor has series poles but they are interpoles, not compound fields. My Monarch manual doesn't even show them but they are there. There is too much junk in the way where the lathe sits right now to trace the wiring to see if the interpoles are reversed. In any case, it wouldn't have severe effects in operation. Interpoles are mainly to reduce brush arcing.

    Bill
    Their purpose on the large-frame, a "Type T" is similar to extra poles on an AC motor, but not quite "fixed" as it is a local-commutator animal, not remote powerplant/VFD "frequency" animal.

    They are part of why it has so much torque at 690 RPM base, can still do useful work at 2400 RPM, and no, they do not reverse w/r the sole and only two-wire Armature input.

    To TWO pair of brushes, lest we forget.

    But that is an overlapped winding mesh thing. It will run with one pair removed, just not as silky-smooth.

    Basically, it is an elevator or hoist motor, and MUST be able to "creep", whether a 10EE used that capability or not.

    If War Two had not seen to Sundstrand being commandeered for crucial hydraulic work, we might still be running "juice" 10EE, albeit more powerful ones than the 1936-39 Sundstrands - instead of electric final-drive.

    Anyhoo.. I prefer it over the 5 HP units, NONE of which are "straight shunt".

    And none of which have but a fraction of the mass of commutator Copper, let alone diameter and swept area, nor the mass, cross-section, or swept area of brush material, either.

    There's a method to that message...



    All that aside.. for THIS machine, THIS drive, I'd recommend at least trialing Field Reversing.

    If it works as expected, the hardware cost is low and the simplicity is a major plus.

    At normal max Armature voltage the 3 HP large frame, installed and belted to a spindle, will not reach stratospheric "squirrel cage" RPM, even with ZERO field.

    There's too much drag. The strength of residual magnetism is degraded too soon. There's ample time for an operator to shut-down the Armature supply as well.
    Last edited by thermite; 08-22-2018 at 04:58 AM.

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    Quote Originally Posted by thermite View Post

    Mechanical contactors need serious attention to detail lest they destroy his fragile SCR's.
    Hi Bill
    Have a single quadrant DC drive (MP25A4) here on the bench- could you elaborate a bit on this? Would appreciate any suggestions about setting up mechanical contactors for reversing (SquareD 8702s with interlock) and also adding braking resistors.

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    I have not read all the posts, so forgive me if I repeat something. I am using the Parker 514/507 setup that Bill developed, and I have wired in relays to make the ELSR work as original. I have cut two threads in the last few weeks with it, approximately 200% more threads than I have cut in the last 5 years, and the auto shut off function of the ELSR is actually kind of nice.

    If this is what you are trying to duplicate I can tell you my setup.

    John

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    Would be great to see your set up- did you do anything special to address potential issues with the SCRs? Interlocks, timers, braking resistors?


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