Hardinge KL-1 feed motor: can you please share volt ratings? - Page 2
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  1. #21
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    I just went to correct my drawing and found I had already corrected checked the diagram posted here and that was correct too !

    Damn I hate getting old !!

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    Quote Originally Posted by Billtodd View Post
    Damn I hate getting old !!
    A privilege. Denied to many.

    Beats all Hell out of the alternative.... so far...

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    Quote Originally Posted by Billtodd View Post
    I just went to correct my drawing and found I had already corrected checked the diagram posted here and that was correct too !

    Damn I hate getting old !!
    First, thanks for rushing to correct the diagram and help others in the future!

    And, only because you mentioned it, your diode-bridge part in the schematic is not correct. Not that it actually matters....

    Quote Originally Posted by thermite View Post
    A privilege. Denied to many.

    Beats all Hell out of the alternative.... so far...
    So true...

  5. #24
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    And, only because you mentioned it, your diode-bridge part in the schematic is not correct. Not that it actually matters....
    That's just plain embarrassing
    Attached Thumbnails Attached Thumbnails hlv-h-397-wiring-diagram-4-4.jpg  

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    A note about what most/all have missed regarding the motor voltages:-
    An inductive load running on DC responds to the average of the voltage, not the RMS value. If the mains were a square wave, the average would equal the RMS value, it ain't so it doesn't. The average value as seen by the motor will be the RMS value (before the rectifier) divided by the form factor, which is 1.11 in the case of a fully rectified sine wave.

    This means that the AC voltage needed to supply 190VDC to the motor is 211V.

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    Quote Originally Posted by Mark Rand View Post
    A note about what most/all have missed regarding the motor voltages:-
    An inductive load running on DC responds to the average of the voltage, not the RMS value. If the mains were a square wave, the average would equal the RMS value, it ain't so it doesn't. The average value as seen by the motor will be the RMS value (before the rectifier) divided by the form factor, which is 1.11 in the case of a fully rectified sine wave.

    This means that the AC voltage needed to supply 190VDC to the motor is 211V.
    Which is kinda strange, because the motor and DC Drive makers specify 230 VAC in for 180 VDC out or 120 VAC in for 90 VDC out.

    All "nominal" numbers, of course. Most of the time we are running a tad above to quite a bit below in variable speed use.

    "And then.." aside from the expected SCR swiching spikes right at the sharp edges, we may get an "AC component" with a good deal more "energy under the curve".

    Example:

    - One-Quadrant, contactor-reversed, Beel/BICL D-510 I had on the bench, over 130 VAC AC component into the test load - a Reliance "small frame" 3 HP motor for a 10EE WiaD era. That drive had exactly two controlled rectifier elements in its 4-element bridge, the other two legs free-running, and but one trigger inductor.

    - Four Quadrant Parker-SSD DC Drive, 52 VAC AC component into the same load, eight trigger inductors, SCR matrix according for bi-directional running, over-run, and regenerative braking control.

    FWIW-not-much under 6 V ripple after the 20 MH ripple-filter was added.

    CAVEAT: Free-running motor, not even a gearbox, so "no load" figures. Fluke & Rigol doing the measuring.

    Small motor as this one here, one of the "nicer" DC Drives for uber-quiet-operation would be a PWM one with a fat filter capacitor and a decent inductor, added.

    One would only even bother chasing reduced noise because Hardinge lathes themselves are among the most nearly silent running, anywhere, ever. Even a 10EE in direct belt is noisier.

    And, of course, we KNOW "quiet" matters so we can "sneak up" on a final fit, yah?


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    "Which is kinda strange, because the motor and DC Drive makers specify 230 VAC in for 180 VDC out or 120 VAC in for 90 VDC out."

    Hardinge made all kinds of feed motor electrics. Some of the early one did have selenium rectifiers which would I believe had eaten
    up some of the voltage.

    Because I haven't seen any photos here there's no way to tell if this feed motor setup is original or has been fiddled with over the years.
    Heck the S/N 330 HLVH that we have here at work is old enough that it has the selenium rectifiers for both armature and field, and a
    variac which is coupled to a large power pot. I seem to recall the variac provides the armature voltage and power pot is used to modify
    the field current - weakening it I guess - at the lower end of the speed range.

    I personally know of at least two vintages of electronic speed control that they used.

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    Quote Originally Posted by jim rozen View Post
    Hardinge made all kinds of feed motor electrics. Some of the early one did have selenium rectifiers which would I believe had eaten
    up some of the voltage.
    The classical Selenium finned stacks are still being made, brand-new, as
    the electroplating industry still uses Seleniums.

    Somebody "may" still make the older-yet Copper-Oxide stacks as look similar but were nearly always black and smaller.

    All the classical recitfiier materials all still "work". They have different characteristics as can be put to advantage - or usta bee - was all.

    Meanwhile, we have learned to "contaminate" ignorant Silicon creatively enough - that "dirty beach sand" thing -to cover most of those needs more cheaply and - usually, at least, in less physical space and with better longevity.

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  13. #29
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    One more go... (as I'm the son of a electrical traction engineer and 'motor' was the first word I could spell)

    Plate rating says : 115vdc (A) 190vdc (F) will give 1750rpm at 1/15hp out all day long (at some temperature that seemed ok)

    put a few more volts in and it will go faster , load it harder and it will put out a bit more power as it draws more amps and get a bit hotter - all day long .

    The plate rating is not the maximum or minimum. It is simply the spec for which the manufacturer/designer was aiming or that the marketing dept. felt they needed.

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    meanwhile, we have learned to "contaminate" ignorant silicon creatively enough - that "dirty beach sand" thing -to cover most of those needs more cheaply and - usually, at least, in less physical space and with better longevity.
    #

    rofl

    :d

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    Hi to all,

    thanks for the info, it's been quite some time since I last had anything to do with motors (this is no excuse though, I should know some of these stuff...).

    Here are some pics from my setup, were not intended for here but you'll figure it out:





    Diodes have been replaced (if there were selenium to begin with) and, also, the Variac has been replaced (I think) (and also repaired by me...). It follows the schematic by Bill, that is, no rheostat for the field coupled to the Variac. I guess this is how the KL1s where sent out.

    Sorry for not being able to report any progress, I was busy cutting some DIN477 threads on my working lathe....oh how I would love the Hardinge for that internal thread with the shoulder....

    But since we got all technical, please clarify these two points:

    - Why is that 10K resistor in the middle of the armature diode bridge there? What's its purpose?
    - Why did some (all (?) the american) models have that rheostat on the field? Why did they need to reduce the field's voltage at the turn of the knob? Was it to help increase RPM?

    Many thanks for all

    BR,
    Thanos

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    The 10k just ensures there is no crazy high fly back voltage stored on the switch contacts & wiring when the motor is switched off (trapped between the diodes and open contacts) that might cause premature failure of the switch.

    The resister and cap across the wiper of the variac is a filter / arc suppressor.

    {edit}

    I have an early US HLV-H diagram (1961?), showing a 90vdc motor (variac coupled 'rheostat' to field) with 0-90vdc armature (with an inline reactor/inductor) and 50ohm brake resister.

    And another, UK diagram (HLV ? ) , from MTC control gear ltd , Leigh on sea , Essex, showing a Hi/Lo speed switched taps on the variac for the field . Probably using a US made feed motor.

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    Quote Originally Posted by Billtodd View Post
    The 10k just ensures there is no crazy high fly back voltage stored on the switch contacts & wiring when the motor is switched off (trapped between the diodes and open contacts) that might cause premature failure of the switch.

    The resister and cap across the wiper of the variac is a filter / arc suppressor.

    {edit}

    I have an early US HLV-H diagram (1961?), showing a 90vdc motor (variac coupled 'rheostat' to field) with 0-90vdc armature (with an inline reactor/inductor) and 50ohm brake resister.

    And another, UK diagram (HLV ? ) , from MTC control gear ltd , Leigh on sea , Essex, showing a Hi/Lo speed switched taps on the variac for the field . Probably using a US made feed motor.
    Right,

    thanks for the 10k explanation, makes sense.

    Regarding the field supply, why did they choose to alter it in some models? Be it rheostat or high/low taps. What do you loose if you keep your field at max voltage VS reducing it for high speed?

    BR,
    Thanos

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    a fixed field current is just like a permanent magnet, except for the power consumption. My guess is they want to reduce power at lower speeds , they also fitted early ones with hi;low speed switches , suggesting power was a problem. Switching to a higher voltage may actually have helped by reducing the current making the variac smaller etc.

    You can control the speed of the motor, either by limiting the power, or limiting the voltage. I suspect the early designs limited the power , whereas the latter one is clearly voltage controlled.

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    Umm. The high speed tapping feeds half the normal voltage to the field windings. One will get more available torque from the motor on the full voltage/low speed setting.

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    Quote Originally Posted by Mark Rand View Post
    Umm. The high speed tapping feeds half the normal voltage to the field windings. One will get more available torque from the motor on the full voltage/low speed setting.
    Lowering the field excitation reduces the back emf making the motor run faster for a given armature excitation (at the cost of some output power)

    Which means the early circuit probably were voltage controlled after all :shrug:

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    Quote Originally Posted by Billtodd View Post
    One more go... (as I'm the son of a electrical traction engineer and 'motor' was the first word I could spell)

    Plate rating says : 115vdc (A) 190vdc (F) will give 1750rpm at 1/15hp out all day long (at some temperature that seemed ok)

    put a few more volts in and it will go faster , load it harder and it will put out a bit more power as it draws more amps and get a bit hotter - all day long .

    The plate rating is not the maximum or minimum. It is simply the spec for which the manufacturer/designer was aiming or that the marketing dept. felt they needed.
    Prezaclty.

    These are, after all, inherently "analog" devices generally rather imperfectly linear,

    All a dataplate represents is a "snapshot" chosen to convey the motor's characteristics at a CONVENIENT and common source of parameters.

    Chosen a-purpose off lots of records as to what metal where, in what shape, how many turns, of what wire, etc. it takes to hit a design goal, of course.

    Not by simply rolling dice and seeing what comes out of an egg.

    Phases, AC.DC, or both, Volts & Hz, where appropriate, mostly, Amps, and HP following inherently,

    Torque spec'ed only if the field of application requires it because it is locked-in mathematically to RPM & HP / KW in all cases, anyway.

    I say again: A dataplate is but a "snapshot" relating any of many possible combinations.

    Done at the conveniece-point where the motor delivers the goods it was meant to deliver.

    They are not meant ot deliver mystery or possible surprises the end-luser has to test for on his own resources as if selecting Avocados in a bin.

    As some among us DO test, out of stubborn curiosity.

    Ex: Why is the original 3 HP large frame Reliance motor of a 10EE such a
    magical performer?

    Well.. to begin with... it isn't really a 3 HP motor.

    It's a de-rated FIVE HP motor happy as a clam to be run at as much as 4.3 HP for 80 years and counting.

    "BFBI" approach? "Sandbagging" the opposition? "G-Damned HOT RODDERS?"

    Who really cares NOW?

    It worked a treat, has lasted a long time, seems good for another hundred years, either way.

    Hardinge probably used "more motor" than they needed to as well. Fools they were never.

    It was meant to "JFDI", solve several problems, create no new ones so customers could separate chips from money, get PAID, do it again faster and better, buy NEW Hardinge lathes to keep-on doing the same, one year after a decade and for scores of years.

    Most of its prior life, it probably did exactly that. Delivered the goods.
    Still, yet, today? "To Be Determined".

    Even the legendary Brothers Bodine once had to run print advertising:

    "Bodine Motors do TOO wear out! They just take longer."



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    Hi guys,

    well, I found some time to check the diode board today. Of course is measures perfectly....
    Only the filter capacitor measures at 160 nF instead of the nominal 100 nF, but I was just using a DMM for that measurement....(and, if that cap was shorted, I would have issues even when the armature was disconnected, since it's connected before the rectifier. But I had no issues when I disconnected the armature).

    So, I'll change all the components as a good measure, I don't have anything else to try at this point anyhow....

    BR,
    Thanos

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    Default guys help....

    So, latest report, not much in terms of progress, hope someone can help:

    I went on and rebuilt the diode board, replaced everything apart from the 220Ohm/10kOhm resistors (didn't find them in that store).

    Anyhow, I installed the diode board, started the system, still the same: transformer buzz and smoke from the variac and fuse blown after around 50% of the dial travel. (note that it's not the fuse that's in series with C/CA that gets burnt, it's the other one that feeds the 230ACV to the power feed driver.

    Indicatively:
    - dial at around 25%, variac output 45VAC. With the left-right switch in the off position, all is well. If I turn the switch to left or right, I am getting around 38VDC to the armature (A1-A2), variac starts buzzing a bit and gets HOT. The problem is that if I connect an Ameter in series with the armature, I am only getting 80 mA!

    - Then replaced the Variac with another one I have. At around 30-40% I am getting around 60 VDC on th armature. The variac again got very hot, I mean very hot to the touch and my hands are very tolerant to the heat...Strange thing is that the motor again only drew around 90 mA....

    - Next, hunting ghosts, I thought I'd dish the diode board (w.r.t. the armature). I connected the output of the variac to a diode bridge I had lying around. Again, same things more or less: 45 VDC at the output of the diode bridge, 90 mA into the armature, but the Variac getting smoking hot. It's the part from the 0% up to the slider that gets hot, rest of the coil is ok.

    Adding to all this the observation from last week: motor (both armature and field) fed by a totally different variac through a diode bridge went full speed at more that 230 V drawing only 300 mA!

    I guess the current that the motor draws is indicative of its health, and this one seems ok. Apparently it's the variac to blame (since it's also the fuse at the input of the variac that gets blown). What troubles me though is that without load (armature) the variac behaves, and that, my second one shows the same issues as well....But, it's not impossible that both lathes had blown variacs....


    Any ideas? On what's going or or what I should check next?

    Thanks for listening...

    BR,
    Thanos

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    So,

    Variac no load is ok ? Where are you measuring volts? At variac? Or motor lead? Switch on or off?

    check you haven't got a shorted loop around variac , i.e no wires that wrap around the torus. No bolts or or mounting hardware that could loop via chassis.

    Have you got a spare goat? (Useful sacrifice when fixing stubborn problem or replacing belts)

    Bill


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