Replacing the Monarch MG
Close
Login to Your Account
Likes Likes:  0
Page 1 of 3 123 LastLast
Results 1 to 20 of 42
  1. #1
    Join Date
    Dec 2002
    Location
    Springdale, Arkansas
    Posts
    18
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Default

    Just removed the MG and installed an offline power supply in a 1942 10ee.
    Seems to have good torque and speed range.
    Need two bits of information before putting the covers on.
    Values -to set the minimum Armature and Field Voltage.
    What polarity -monarch used, for field connections- in the conduit box.

    Thanks,
    Jim_J


  2. #2
    Join Date
    Dec 2002
    Location
    Monterey Bay, California
    Posts
    10,260
    Post Thanks / Like
    Likes (Given)
    28
    Likes (Received)
    213

    Default


    GA1 is positive with respect to GA2. GA2 is the common terminal of the Series Field circuit.

    E1 is positive with respect to E2. E2 is the common terminal of the Shunt Field circuit.

    E1-2 supplies the Motor (Shunt Field) Rheostat, and the reduced field voltage is applied to F2. Strangely, and inconsistently, F1 is the common, and hence the negative shunt field terminal.

    Question: how are you reversing the motor, as it is a compound wound dc machine, and the series field polarity must be maintained while the armature (which is in series relation with the series field) must be reversed (by contactors F and R, in the Ward-Leonard drive). IOW, the motor is a "six terminal" machine.

  3. #3
    Join Date
    Dec 2002
    Location
    Springdale, Arkansas
    Posts
    18
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Default

    Thanks, if I remember correctly the conduit box in this machine has a barrier strip, with only four connections. Was compound an option??
    Will double check when home.
    The present field connection is: 115VDC going to the terminals marked F1 @ F2 ,
    -with no idea of the correct polarity or minimum recommended field voltage.

    Reversing the motor. At this time it isn't possible, the control box -has missing
    parts. Will give that attention after the power supply is trimmed up.

    Jim


  4. #4
    Join Date
    Dec 2002
    Location
    Monterey Bay, California
    Posts
    10,260
    Post Thanks / Like
    Likes (Given)
    28
    Likes (Received)
    213

    Default


    The Reliance motor (3 HP) in my 1956 10EE (tube drive) has six leads.

    The GE motor (5 HP) I have as a spare also has six leads.

    All 10EEs which originally had dc drives, which means from the Ward-Leonard model (circa 1943, or perhaps earlier) to the last all solid-state model (circa 1980s ?) used a compound wound motor.

    A shunt wound motor can only achieve its "base speed", which is usually around 1600 rpm.

    A compound wound motor can achieve speeds above its base speed ... up to whatever its maximum safe speed may be, which is around 4,000 rpm for the 10EE motors ... through the "field crossover" (AKA, "field weakening") technique.

    Because of the necessity of constantly having the shunt field energized, in order to protect the motor from overspeeding and self-destructing, the way the 10EE motor is reversed is to maintain the polarity of the series field, while reversing the polarity of the armature.

    This necessitates the *huge* contactors, which have to control about 4 or so kilowatts of dc.

  5. #5
    Join Date
    Dec 2002
    Location
    Springdale, Arkansas
    Posts
    18
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Default

    Checked the motor data plate.
    It listed the motor as Shunt wound, and if I understand you correctly, it's limited to base speed -as field weakening is only permitted on the later compound wound units?
    I can live with that.

    "Contactors for armature reversal."
    .. Understand about the size! and opted for a simpler, more compact option
    Intend to use: see http://www.paladino.info/~jim/10EE
    Thanks for the info.

    Jim



    [This message has been edited by Jim_J (edited 04-21-2003).]

  6. #6
    J Tiers Guest

    Default

    I would think you can do "some" field weakening, the issue is stability.

    A "lot" of field weakening will make the motor unstable and not hold speed well unless there is a series field included.

  7. #7
    Join Date
    Dec 2002
    Location
    Monterey Bay, California
    Posts
    10,260
    Post Thanks / Like
    Likes (Given)
    28
    Likes (Received)
    213

    Default


    I double checked and triple checked the nameplate data on the 5 HP GE motor which was removed from my machine's sibling when it (my 10EE's sibling) was converted to a VFD drive.

    The complete nameplate data is ...

    GENERAL ELECTRIC
    KINA-MATIC DIRECT CURRENT MOTOR
    HP: 5 / VOLTS: 240 / AMPS: 18.1
    RPM: 1150/3450 / WOUND: SPEC. COMP.
    FLD AMPS: 1.19/0.72 / FLD OHMS: 78
    DUTY: (BLANK) / ENCL: DP / S.F.: 1.0
    NOTES: MACH. TOOL DUTY SEP EXC 120 V
    MOD: 5CD218E63A / SER: USI-13

    ... which I interpret to mean a "special" compound dc machine, one with a 240 volt armature (and series field) and with a 120 volt (shunt) field which measures 78 ohms, and draws 1.19 amps at maximum (shunt) field voltage and 0.72 amps at minimum (shunt) field voltage.

    There are a total of eight wires in the motor's junction box (AKA, the "peckerhead"), of which six are brought out and tagged with the usual Monarch indicia.

    My guess is this is one of the many compound wound motors which actually has two shunt windings, and which can have the shunt field operated in series or in parallel, hence why only six wires exit the junction box.

    This motor is as removed from the sibling, and is complete with the back gear assembly and the pulley retainer, but not the pulley itself (which was possibly transplanted to the sibling's replacement motor, or may have been discarded).

  8. #8
    Join Date
    Dec 2002
    Location
    Springdale, Arkansas
    Posts
    18
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Default

    That's some motor. Thanks for the info.

    From the other post.
    Is there a way to test the stability issue?
    (i.e. a certain depth cut with reduced field voltage)

    Presently have a temporary offline supply hooked up that allows
    individual armature and field control.
    Perhaps a picture would make more sense?
    Will take care of that.

    What am I missing on the new field module?
    The design has:
    1.) low field current detect. (to disable armature voltage)
    2.) a input to force full field voltage (remote pot over-ride)
    3.) a input to kill field voltage (field timer controlled)
    4.) a input for a remote speed pot.

    Construction of the new field design hasn't been submitted yet. Will just
    leave the voltage reduction ability for possible use.

  9. #9
    Join Date
    Dec 2002
    Location
    Monterey Bay, California
    Posts
    10,260
    Post Thanks / Like
    Likes (Given)
    28
    Likes (Received)
    213

    Default


    A pure shunt wound dc machine has no series field, hence there are no separate field windings to cumulatively or differentially excite.

    Therefore, a shunt wound motor would only be expected to achieve its "base speed", and no higher, as there is no interaction between the series and shunt fields, which facilitates the cumulative or differential operation of such a (compound) dc machine.

    Bottom line ...

    1) a shunt wound motor can only achieve its base speed,

    2) a series wound motor can achieve, theoretically, a very high speed, but one which may cause "bird caging" (i.e., spontaneous destruction) of the armature, and

    3) a compound wound motor can achieve both its base speed (under the conditions of name plate maximum shunt field), and can also achieve significantly higher than its base speed (under the conditions of "field crossover"/"field weakening", and the conditions of name plate minimum shunt field).

    The "special compound wound" motor from my 10EE's sibling (motor nameplate data previously posted) clearly delineates the extrema of its designed operation, which I believe may have been 3,000 rpm, maximum, or, possibly, 4000 rpm, maximum, measured by the 10EE's spindle (mechanical) tachometer.

  10. #10
    Join Date
    Dec 2002
    Location
    Springdale, Arkansas
    Posts
    18
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Default

    OK, sounds like you have experience with DC motors.
    It's a bit out of my field, will see if there's any information
    in the tech library Monday.

    Will leave the field control in the design in case I run across
    a compound wound motor?

    Doubt if Tim will finish it before Friday.

    From the previous post.
    Pictures of the temp power supply are at:
    http://www.paladino.info/~jim/ps1.html
    http://www.paladino.info/~jim/ps2.html

    Thanks for the help,
    Jim

  11. #11

    Default

    The 5HP GE motor is reconnectable on the field voltage for 120 or 240, be very careful the leads were not marked F1,2,3, or 4, on my motor, and whoever did the original control conversion in 1990 wired the 120V field to a 200V field supply on the controller and one of the field coils got fried.It was a costly rewind job.

  12. #12
    Join Date
    Dec 2002
    Location
    Monterey Bay, California
    Posts
    10,260
    Post Thanks / Like
    Likes (Given)
    28
    Likes (Received)
    213

    Default


    I have reviewed the schematic diagrams of the Ward-Leonard, WiaD and Modular 10EE drives.

    I was in error; the Ward-Leonard drive uses a shunt motor, one with a base speed of 690 rpm, and which can achieve 2400 rpm, maximum, through reduction of the shunt field voltage, while the armature remains at 230 volts. The shunt field is stated to be 115 volts, maximum. The capacity of the exciter is not stated. Therefore, the Ward-Leonard drive motor is a 4-wire shunt wound dc machine, and reversing is accomplished by reversing the polarity of the armature.

    The WaiD and Modular drives both use a compound motor. Therefore, these drives both use a 6-wire compound wound dc machines; reversing is also accomplished by reversing the polarity of the armature, while maintaining the polarity of the series field.

    The use of a compound wound dc drive motor improves the 10EE's load regulation, while facilitating an increase in spindle speed from 3,000 rpm to 4,000 rpm, with complete stability.

  13. #13
    Join Date
    Sep 2002
    Location
    Salinas, CA USA
    Posts
    3,869
    Post Thanks / Like
    Likes (Given)
    197
    Likes (Received)
    172

    Default

    Peter, interesting info. I always had assumed that WIAD and MG motors are the
    same. The controllers are very similar,
    i.e. the electrics, in fact I converted
    a WIAD controller to a MG controller, just
    by rerunning the jumpers between posts and
    the various components on the board. The
    WIAD controller had some extra labelled
    posts and there were several changes to
    the jumpers. I had one of each box in hand,
    so doing the conversion was just a matter of
    matching up the wiring.

    Should it be possible to use a WIAD motor
    on a MG machine (possibly by using a WIAD controller?)

    -Dave

  14. #14
    J Tiers Guest

    Default

    PeterH:

    Is your Ward-Leonard schematic in electronically transmittable form? I have aquired schemos for the other types from carious people, but not for that one.

    If you have it in a computer file form, I would appreciate it if you could email me a copy at your convenience.

  15. #15
    Join Date
    Dec 2002
    Location
    Monterey Bay, California
    Posts
    10,260
    Post Thanks / Like
    Likes (Given)
    28
    Likes (Received)
    213

    Default


    J Tiers ...

    I can snail-mail you a copy of the Ward-Leonard 10EE's schematic. Contact me off-List.

    rimcanyon ...

    It should be possible to use a WiaD or Modular motor in a Ward-Leonard 10EE. The motor's series field, with labels S1 and S2 would be connected outside of the reversing circuit which includes the armature, on the AP relay side of the reverser, not the Dynamic Brake resistor side of the reverser.

  16. #16
    Join Date
    Dec 2002
    Location
    Springdale, Arkansas
    Posts
    18
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Default

    Your right on regarding the base speed. With an electrical tach. it measured
    680rpm . With -the present trim on the power supply- the low speed
    is 200rpm and max. 1400rpm.

    It seems this motors original field minimum should be about 20V??
    With -field voltage at 114V- the current measured 1.51A, and
    the original field resistor is about 370 ohms.

    I'm still unsure what you were saying about; shunt wound and stability.
    That is -with field weakening what are the unstable parameters??


  17. #17
    Join Date
    Dec 2002
    Location
    Monterey Bay, California
    Posts
    10,260
    Post Thanks / Like
    Likes (Given)
    28
    Likes (Received)
    213

    Default


    A "pure" shunt wound motor has the (shunt) field connected directly across the armature. There can be no instability in this connection.

    When a shunt wound motor is operated with separate supplies for the armature and the field, loss of the field supply will cause the motor to run away.

    In the WiaD and Modular 10EEs, this runaway is prevented by the Field Loss (FL) relay.

    Apparently, Monarch's engineers felt it was not necessary to include an FL relay in the Ward-Leonard model as loss of the drive motor's field implicitly means loss of the generator's excitation as well, thereby protecting the entire drive, including the motor.

    Instability in a compound motor results when the shunt field is weakened too much. This is prevented in the WiaD and Modular drives by the proper setting of the Max Speed potentiometer, backed up by the FL relay.

    A replacement drive would have to take all of these issues into consideration, and to provide for these functions by some means. Which is why I originally suggested salvaging the Overload (OL) and Field Loss (FL) relays from an existing WiaD or Modular drive, when planning a conversion to third-party, "packaged" drives, such as the previously mentioned KB Electronics models.

  18. #18
    J Tiers Guest

    Default

    PeterH:
    Thanks, I will email you.

    I am not so sure that a pure shunt motor will run away under any conditions, as loss of field means loss of torque, and a slowdown. The back EMF will collapse and the motor will trip the overload, because there isn't enough torque to overcome friction.
    If there were enough residual magnetism, there might be torque enough to go at a pretty high speed, but usually that isn't sufficient.

    In a series motor or compound motor with sufficient series field, increased current as the back EMF collapses will also increase the field, keeping it just sufficient to accelerate the motor to hold up the back EMF. The feedback mechanism is what allows runaway, and it is lacking in the pure shunt motor.

    The Monarch compound motor will work fine at 12V on the shunt field, suggesting that it might be able to run away on the series field.

  19. #19
    Join Date
    Dec 2002
    Location
    Monterey Bay, California
    Posts
    10,260
    Post Thanks / Like
    Likes (Given)
    28
    Likes (Received)
    213

    Default


    I was thinking that the "interpoles", which are indeed present in the Ward-Leonard Monarch's shunt wound motor, might allow for loss of field to potentially cause some stability or runaway problems.

    Perhaps I'll go back to my electric machines text books and review the function of interpoles. It's been a few years since I cracked those books!

    Basically, loss of drive motor (shunt) field in a Ward-Leonard 10EE also means loss of generator excitation, which implicitly protects the drive and motor.

  20. #20
    Join Date
    Feb 2002
    Location
    Peralta, NM USA
    Posts
    5,631
    Post Thanks / Like
    Likes (Given)
    48
    Likes (Received)
    456

    Default

    One thing I've always wondered about - as I undertsnad it the series field can be wired either in support of the armature or in opposition to it (those may not be the right terms, they're just what comes to mind right now). What's the difference in the motor's behaviour? The reason I ask is that I've never been sure if mine is marked properly since the trip through the repair shop...


Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •