Questions about determining health of Reliance DC motor
Close
Login to Your Account
Results 1 to 10 of 10
  1. #1
    Join Date
    Jun 2011
    Location
    Atlanta, GA, USA
    Posts
    39
    Post Thanks / Like
    Likes (Given)
    42
    Likes (Received)
    6

    Default Questions about determining health of Reliance DC motor

    Hi Folks,

    I'm considering reusing the existing 3HP Reliance shunt wound DC motor that came with my machine and just mating it with a modern DC Drive that can be obtained for a few hundred dollars. Before I spend on the DC drive, I'd like to make sure the motor is good!

    I read up on all the electrical tests I can do without having a megger, and all looks good save for some odd behavior I'm seeing on the commutator bars.

    AFAIK each pair of bars separated by 180* should have the same resistance, and each neighboring set of bars should have no continuity. When I started to measure, I discovered that 100% of the commutator bars are continuous to one another (but none of them are continuous to ground or the lamination stack).

    Is the armature hooped, or am I missing something peculiar about the construction of this specific model? Photo of nameplate and armature are below. The commutator bars I am testing are at bottom, obvs.

    --jim

    img_0492.jpgimg_0490.jpg

  2. #2
    Join Date
    Sep 2002
    Country
    UNITED STATES
    State/Province
    Arizona
    Posts
    3,631
    Post Thanks / Like
    Likes (Given)
    828
    Likes (Received)
    482

    Default

    What's serial number and build date of the machine? What type of drive did it originally have? It's hard to read the data plate, it doesn't look like that for motor/generator (MG) drive machines. In particular, it lists the RPM range as 1100|4000, whereas the typical MG machine has a motor with and RPM rating of 690|2400. I can't read the field resistance information on the plate.

    There are a number of different ways that an armature can be wound and I don't know for sure which method was used on the Reliance 10EE motors. Here's a link that discusses armature windings: Monarch 10EE Motor Generator Troubleshooting

    It's not true that adjacent bars will have no continuity. Unless it's a really strange winding method, you should find that all of the windings are connected together in series, in a big ring. (The above link explains this.)

    Here's what I got when I did some measurements on a square-dial MG spindle motor several years ago:
    • Number of Brushes: 4
    • Number of Bars: 87
    • Resistance Bar to Bar: < 0.2 Ohms
    • Inductance Bar to Bar: 75 micro Henrys
    • Resistance at 90 degrees: 5 Ohms
    • Resistance at 180 degrees: 0 Ohms
    • Field Winding Resistance: 84 Ohms


    I think the above makes it a simplex wave winding, but I'm not really sure. (The zero Ohm reading at 180 degrees doesn't make sense.) Maybe hitandmiss Bill can tell for sure what I've got.

    Cal

  3. #3
    Join Date
    Nov 2004
    Location
    Webster Groves, MO
    Posts
    7,260
    Post Thanks / Like
    Likes (Given)
    1822
    Likes (Received)
    3309

    Default

    Trying to read an armature with a typical digital meter usually means reading the resistance of the leads more than the armature. I have a Wheatstone bridge made by Leeds & Northrup that reads milliohms with Kelvin leads. I got it from a retired Century Electric engineer who used it on their motors. I have been contemplating doing some analysis on the armature for a different reason. As it is used, the insulation needs to withstand 250 volts between the coils and core, assuming one brush grounded and the other at full voltage. I want to see if the insulation is laid out so it can be run with one brush positive 250 volts and the other negative 250. That would move the base speed up and reduce the field weakened range.

    BTW, the 180 degree apart brushes are at the same voltage and the two 90 degree away ones are at the other polarity. You could run the motor, at a lower output, of course, by only energizing two brushes 90 degrees apart.

    I may try running mine at +250 and -250, but it will be with a filtered supply. I would not consider torturing the motor with a switcher.

    If I just wanted to make chips and the MG unit was working properly, I would not consider changing it. There is a lot more to the system than just putting voltage on the motor. It seems to be a knee jerk response from people when they first get one of these machines to rip out all that obsolete junk and put in a "modern" supply. Unless you really know what you are doing, the odds of coming out with a better machine are slim.

    Definitely check it with a megger. I have one, but St. Louis to Atlanta is a long drive.

    Bill

  4. Likes rakort liked this post
  5. #4
    Join Date
    Sep 2011
    Country
    UNITED STATES
    State/Province
    Virginia
    Posts
    27,282
    Post Thanks / Like
    Likes (Given)
    7561
    Likes (Received)
    8507

    Default

    Quote Originally Posted by jim314159 View Post
    Hi Folks,

    I'm considering reusing the existing 3HP Reliance shunt wound DC motor that came with my machine and just mating it with a modern DC Drive that can be obtained for a few hundred dollars. Before I spend on the DC drive, I'd like to make sure the motor is good!

    I read up on all the electrical tests I can do without having a megger, and all looks good save for some odd behavior I'm seeing on the commutator bars.

    AFAIK each pair of bars separated by 180* should have the same resistance, and each neighboring set of bars should have no continuity. When I started to measure, I discovered that 100% of the commutator bars are continuous to one another (but none of them are continuous to ground or the lamination stack).

    Is the armature hooped, or am I missing something peculiar about the construction of this specific model? Photo of nameplate and armature are below. The commutator bars I am testing are at bottom, obvs.

    --jim

    img_0492.jpgimg_0490.jpg
    That's the "small frame" 3 HP Reliance used in the WiaD (first generation tube drive) 10EE. Also - with GE tachogenerator - certain DoD "upgrades" to a whole tribe of early-generation DC Drives. Just sold one of those motors to put another 10EE back to work.

    It is a "Type T" compensated shunt. Six wires. A1-A2, F1-F2, S1-S2

    DC motors of the era didn't GET but a little bit more "peculiar". Added compounded compensation, 8 wires on those ones.

    Interleaved mesh coil pattern for uber-smooth running over a wide speed range, not so great efficiency as the modest penalty.

    Cheapest restoral is to keep the OEM WiaD tube drive if you still have it. Dirt-simple. Low parts-count. Was tuned to that motor.

    Big fat, hard to find, tubes now have a member-built SCR wire-in replacement that has been working well.


    The "DC Drive" it otherwise needs to run well also needs support goods. Figure closer to $2,000 -$3,000, all new parts, maybe $900-1200 with used drives.

    That's your "few hundred".

    Trying to run a 230 VDC Type T that Monarch/Reliance pushed to 250-260 VDC or so off any of many 180 VDC-out DC drive (KBRG-255 in my tests) is akin to drinking beef stew through a cushion-sole woolen GI boot sock.

    Might keep you alive, but it surely gets right TEDIOUS!



    To wit:

    Three-phase power, if yah got it, DC drive around $1,200 to $2,500 +, used.

    Single Phase Power if yah do NOT have 3-Phase:

    - Boost transformer, 240 VAC to ~ 290-340 VAC, 320 about right, and full-isolation, not autotransformer. DC drives are NOISY, this serves as "drive Isolation" transformer. Usually done by paralleling two if not three common units, primary side, secondaries in series.

    - Ripple Filter. 20 mHenry choke @ 20 A. Stock Hammond part. just under $300, most-recent two purchased. Lenze "swinging" choke if you can find one. ISTR mine is 16A, has a wider range of impedance, load dependent..

    - Armature DC Drive: Eurotherm/Parker-SSD 514C-16. Around $400 used? ISTR around $1200 new? Check the current price.

    - Field DC Drive. KB, Minarik, Dart, Danfoss-Graham can DO that, but the Eurotherm/Parker-SSD 506, 507, or 508 units are easier for the Field because they have compatible alarm signals as can be directly connected to the 514C-16 to cover Field loss or Field too low.

    Coupla potentiometers, a few switches, fuses & block, a decent disconnect.

    That's the core of it, large-frame 3 HP, small frame 3 HP, or 5 HP.

    The 514C-16 is a "4Q" or "regenerative" drive so no need of any relays nor contactors nor braking resistors at all. None. Zero.

    Clean up the commutator. Re-assemble. Seat new brushes. Try it off a car battery, no field power ELSE 12V on the field as well. It should turn slow, but smoothly if it is OK.

    Dataplate shows where to connect the "S" leads. Use the option for "Forward" rotation. It will fight the Drive's regulation when in reverse, but no Big deal.

    OEM WiaD? Follow Monarch's schematic.

    Plenty more help on specifics if you have the WiaD and tubes, or go for the DC drive either one. Whichever way you choose to go. PM community has been there, can assist.

    We'll even still talk to you if you decide to go for a VFD and 3-P motor. Might chuckle a bit atcha struggling in our collective rear-view mirror. Dinosaur Current has its ways.

    So does ABB/Baldor/Reliance. Comparable DC motor, new, is prolly above ten thousand US$, quantity ONE.

    And it won't FIT the space available and still mount the gearbox. DAMHIKT, but at least the RPM III type TR was only about $800 and a 1,000 mile r/t go-fetch, used.

    MSRP? Reliance was getting around $11,000 with the tachgenerator and mount. Years ago.



  6. #5
    Join Date
    Sep 2011
    Country
    UNITED STATES
    State/Province
    Virginia
    Posts
    27,282
    Post Thanks / Like
    Likes (Given)
    7561
    Likes (Received)
    8507

    Default

    Quote Originally Posted by 9100 View Post
    you really know what you are doing, the odds of coming out with a better machine are slim.
    About $6,000 invested improved the odds. I needed a new 4-trace scope and nicer meters and more of them and..and .. that nice vari-tap transformer you provided and a 20 A Variac and.. a whole PILE of stuff and "extra" motors to test to destruction if they hadn't been as tough as they be.

    "Better"? Only in parts. An SSD can produce about 4.3 HP from the nominal 3 HP, bump-up the torque, provide 20A to locked rotor or near-as dammit, ergo full RPM clear down to silly-low RPM. One turn in fifteen seconds? Perhaps slower? But it is a mere parlour-trick.

    Run what Monarch shipped will usually be least-cost, least-hassle, most grins.
    Even cash left for some TOOLING.

    But we DO have plenty of choices by now. "Macona" even wrote up servo drives.

    No 10EE need "go dark" as to motive-power-impossible.

  7. #6
    Join Date
    Jul 2010
    Location
    Rochester, NY USA
    Posts
    2,171
    Post Thanks / Like
    Likes (Given)
    10
    Likes (Received)
    507

    Default

    Quote Originally Posted by jim314159 View Post
    Hi Folks,

    I'm considering reusing the existing 3HP Reliance shunt wound DC motor that came with my machine and just mating it with a modern DC Drive that can be obtained for a few hundred dollars. Before I spend on the DC drive, I'd like to make sure the motor is good!

    I read up on all the electrical tests I can do without having a megger, and all looks good save for some odd behavior I'm seeing on the commutator bars.

    AFAIK each pair of bars separated by 180* should have the same resistance, and each neighboring set of bars should have no continuity. When I started to measure, I discovered that 100% of the commutator bars are continuous to one another (but none of them are continuous to ground or the lamination stack).

    Is the armature hooped, or am I missing something peculiar about the construction of this specific model? Photo of nameplate and armature are below. The commutator bars I am testing are at bottom, obvs.

    --jim

    img_0492.jpgimg_0490.jpg
    There is some basic errors in your thinking.
    1. There should be an odd number of bars on the commutator, so there is no opposite bar at 180°.
    2. There is usually an odd number of slots for the wire, and 2 or 3 coils per slot.

    3. "and each neighboring set of bars should have no continuity." this is completely wrong.
    "100% of the commutator bars are continuous to one another" This is correct.
    See the link in post #2.

    If all the commutator has an even brown color with no burns, I would put it back together and wire in the S field and Armature, along with the F leads. Observe polarity as shown on the nameplate. It should turn smoothly powered from a 12 Volt car battery.

    Hope this helps,
    Bill

  8. #7
    Join Date
    Nov 2004
    Location
    Webster Groves, MO
    Posts
    7,260
    Post Thanks / Like
    Likes (Given)
    1822
    Likes (Received)
    3309

    Default

    Quote Originally Posted by hitandmiss View Post
    2. There is usually an odd number of slots for the wire, and 2 or 3 coils per slot.
    That is one reason these motors cost so much. I used to repair GE tachometer generators with a similar armature. There were three coils per slot, but they were wound one coil in a slot, move to the next and wind one coil, and so on around the armature, then wind the second coil in the first slot, go around and wind the third in each slot, each coil connected to a different commutator bar. In other words, as much work as winding three typical motors. The result was that the output had a very small ripple, like you would get full wave rectifying something like 12 phase AC.

    The winding shop we sent them to would wind all three coils in a slot, then move to the next. The output would still have the tiny ripple peaks but it would staircase up three peaks, then down three peaks. I'm sure the motors in question would have the first winding pattern because the second would have a slight surging as it went up and down the coils. Did anyone say "labor intensive"?

    I have a large frame 3 hp motor and if it wasn't such a monster, it would make a good servo motor. If you want to get the most performance, feed it pure DC, no ripple or pulses.

    Bill

    PS, most of the tach generators came from the local GE shop. They often were run until the bearings were dust and we had to sleeve the chewed up shafts and recalibrate them. I asked who was running them that hard and the reply was that they came from a pornography printer across the river in IL. I guess business was good.

  9. #8
    Join Date
    Sep 2011
    Country
    UNITED STATES
    State/Province
    Virginia
    Posts
    27,282
    Post Thanks / Like
    Likes (Given)
    7561
    Likes (Received)
    8507

    Default

    Quote Originally Posted by 9100 View Post
    That is one reason these motors cost so much. I used to repair GE tachometer generators with a similar armature. There were three coils per slot, but they were wound one coil in a slot, move to the next and wind one coil, and so on around the armature, then wind the second coil in the first slot, go around and wind the third in each slot, each coil connected to a different commutator bar. In other words, as much work as winding three typical motors. The result was that the output had a very small ripple, like you would get full wave rectifying something like 12 phase AC.
    I suspect better, even, than 24 pole, given the brushes usually span 2 3 2 3 2 3 as "transfer" form contacts, never but the one segment?

    The 3 HP small-frame I shipped recently had been acquired from PaulM in Upton, Mass. There had been a soda-can size GE tachogenerator on it.
    AFAIK, that was one of the DoD refurb's with early solid-state DC Drives, not Monarch's doing.

    I asked Paul to keep the tacho and peddle it separately, as it was (still is?) a current Grainger listing at IIRC, $1,100. I have Servo-Tek's tinier ones.

    Now - the damaged motor it replaced is IIRC still sitting in Las Vegas.

    If the PM member as owns it is up for it, I'd like to see if you are up for delving into a rewind and DOCUMENTING - as few others we know could do as well.

    One more old mystery finally resolved and put into PM's record.

    I'm certain as houses the "large frame" 3 HP is wound differently.
    Same goal.

    Covering a second "partial" mystery, as you have reported a few nuggets on this motor years ago.

    I have the one here that actually survived the destructive tests that pushed it into commutator arc-flash. At which point I quit! It runs, but at least a look-see and re-impregnation, new end leads is wise. Full rewind, better yet.

    I could ship you that one so you need not mess with the one you have still in better shape.

    If you could give some thought as to the COST of a documented rewind project, I can cover a least part of it just for the gain in what we know.

    The community - and/or those among us in need of recently re-done motors could cover a portion of the costs as well.

    I still have 3 other ones for two lathes, so "I'm good" without having the donated motor back.

    I know how bleedin' TEDIOUS these can be, and it isn't just "pocket change" involved.

    But when .. next.. or ever.. are we likely to have as good an opportunity to get a properly documented explanation for posterity out of such an effort?

    And might it not be valuable going loooong years forward, when motor shops as have the lore on old DC motors of these type, be they out of lathes, lifts, hoists, etc are so rare, they'd otherwise make the same mistake as was made on the tachogenerators and degrade the motor accidentally?

    (Young-er) Bill

  10. #9
    Join Date
    Jun 2007
    Country
    UNITED STATES
    State/Province
    Nevada
    Posts
    472
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    53

    Default

    I am the owner of Bill’s former small frame Reliance, Presently in my lathe. My original motor with the smoked armature I took to a motor rebuilding shop and was quoted minimum $1500 for a rewind, and that was from the front desk, not the man who actually does the rewinding. I would guess that once he got into the Type T armature from 1956 the cost would be higher. I can attest to the operation with Parker 514/507. Quite good.

  11. #10
    Join Date
    Sep 2011
    Country
    UNITED STATES
    State/Province
    Virginia
    Posts
    27,282
    Post Thanks / Like
    Likes (Given)
    7561
    Likes (Received)
    8507

    Default

    Quote Originally Posted by bll230 View Post
    I am the owner of Bill’s former small frame Reliance, Presently in my lathe. My original motor with the smoked armature I took to a motor rebuilding shop and was quoted minimum $1500 for a rewind, and that was from the front desk, not the man who actually does the rewinding. I would guess that once he got into the Type T armature from 1956 the cost would be higher. I can attest to the operation with Parker 514/507. Quite good.
    I'm not figuring asking 9100 Bill P to work for free, either.

    He's not even the only PM member as knows motor rebuilding/rewinding, but..

    The advantage is that as an RPE who can rewind as a secondary skillset, and "has the knowledge", LOTS of it .. PM's Monarch community could get a sound analysis documented out of the effort. As well as another known-good motor restored for the NEXT "emergency" Or even two?

    Time could come we'd not be ABLE to get these legacy motors properly rewound - ANYWHERE - without that gone-rare information.

    Or not as affordably, anyway.

    I'd class that more an "investment" or "future-proofing" than anything else.

    Some of us may still be getting younger. Bill P. or I? Maybe not so much.

    Task us while you still can do.


Tags for this Thread

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
  •