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vacuum pump help

Discussion in 'Electronic Basics' started by [email protected], Apr 6, 2005.

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  1. Guest

    i hope somebody can help me. i bought a doerr pump at a garage sale the
    other day. they guy tol dme it had never been used but tis a little
    old. it has a strange plug almost looks like a 240 volt. but the pump
    says that its 115v. i know very little about motors! when i connect it
    to my outlet with some wires.. it makes a humming noise and starts to
    heat up. the motor is defineitly not spinning. im pretty sure the pump
    works, im just doing something wrong. any ideas? the following is on
    the pump patent:3311293 insul class a 5.4 A 60HZ 1725 rpm 1/4 hp mod no
    0522v103c(?)186 single phase mtr ref 50156aa733 fr h487. thanks for
    your help!
  2. Lord Garth

    Lord Garth Guest

    The motor might have a bad start capacitor. However, you have not said
    what type of motor is on the pump. The motor could be a universal type
    or an inductive type. The universal type has brushes and a commutator ring.
    That would be the type with a capacitor for startup.

  3. I've not looked up your motor, but suggest this:

    Be sure that your motor is not supposed to be driven
    from 3 phase power. Giving single phase power to
    such a device is a recipe for nothing good and maybe
    a ruined motor. That plug may well be intended for
    a 3 phase connection. (The "single phase mtr" you
    quote suggests otherwise, but a 1/4 horsepower
    motor should not need an unusual plug just to get
    single phase 115 VAC.)

    If you become convinced it is really a single phase
    motor, see if there is a "starter capacitor" on the motor.
    This device, when present, is often concealed in a little
    hump that breaks the more rounded outline of the
    motor housing. It may have gone bad with age. One
    symptom of its failure is failure to start rotating along
    with some buzzing and excess heating. (However, such
    motors generally have an overload cutout switch that
    will click in an out during the stall.)
  4. Guest

    thank you very much for the replys! im goign to go open up what i think
    may be the capacitor casing. how can i tell if the capacitor is any
    good? the only electrical meter i have is for measuring resistence. im
    thinking the plug may be weird because of the motors age??? thanks again

  5. If you can temporarily unload the motor, (so it need
    not drive anything), power it up, give its shaft a good
    spin by hand or wound rope to get it started, then, if
    it runs fast without overheating, the chances are very
    good that just replacing that starting cap will solve any
    problem at the motor. It could be that it is stalling due
    to congealed lubricant or something in the mechanism.
    It would not hurt to get that rotating as freely as you can.
  6. Guest

    i took out what i think is the capacitor. it has two wires going into
    it and one other place where a wire can be connected. the back of it
    (opposite the wires) is open and there is a metal disk that has a screw
    righ tin the middle (variable?). like i said i have no idea what im
    talking about lol. im not seeing any units of capacitence or anything
    really. it does say pat 2585704 & others. also says klixon and
    mee26rx-368 each terminal is numberd 1-3 thanks for your help! id hate
    to see an expensive pump (that i got for $20 :) ) go to waste!

  7. I could not find that patent # at .

    The middle screw is probably for mounting. There
    should be some kind of marking for the capacitance.
    (Or maybe not that long ago.) If you take the part
    to an appliance repair place, and tell them it is for an
    old 1/4 HP motor, they may be able to find another
    starter cap that would work.

    But before replacing it, (unless you want to just go
    ahead and spend money), I would try the free-running
    hand-start experiment. If the motor will not run under
    those conditions, it needs more help than a new cap.
  8. Woops, wrong search function. That patent appears
    to have been issued in 1952 for a thermostat device.
    I'm guessing it is the motor's thermal cutout for when
    the starting or main winding overheats.

    The only real use of this info is that it dates the motor.
    That starting cap is very likely dried out a half century
    later. I would replace it without further ado.
  9. Don Bruder

    Don Bruder Guest

    Please attempt to describe (or better yet, if you've got the gear to do
    so, snap a good clear picture of it, jpeg it down to a reasonable size
    and put it online someplace, then post a pointer to it here) the plug a
    bit better than "weird"?

    Two vertical blades? One vertical, one horizontal? Both horizontal?
    Three blades in a roughly circular pattern? Two round pins? Four blades
    in a circle? Two *LARGE* blades plus a largish round pin? One blade
    vertical, the other blade an "L" shape, plus a round pin? Something else?

    Knowing *EXACTLY* what the plug looks like *CAN* (unfortunately, not
    "will") give a good idea of what kind of juice it wants, but describing
    it as "weird" is just about as useful as a screen door on a submarine in
    terms of figuring out what it expects to be fed.

    And as a bit of advice: If you need to ask "How can I tell if a
    capacitor is any good?", then quite frankly (and with apologies in
    advance for what's probably going to sound like a slam or a putdown, but
    isn't intended to be one) you aren't qualified to consider opening the
    beast up, and you should make no attempt to do so unless you don't care
    that you'll probably screw something up (possibly including yourself...
    Electricity's "bite" is MUCH worse than its "bark") beyond repair.

    You've already gone FAR beyond what I'd recommend for anyone with what
    your level of expertise seems to be by dinking around trying to run it
    from an wires jury-rigged to an incompatible socket. Hell, to lay it all
    out there for everyone to see, you've already gone further than *I*
    would have, and I'm far from being a beginner at the electricity and
    electronics game. If you're lucky, you didn't damage it. If you're not,
    you may well have "smoke-tested" it, and it's never going to run no
    matter what you do. The very fact that you need to ask "how do I..."
    says that you're tinkering with something you don't have the proper
    knowledge to be messing around with without standing a very good chance
    of trashing it.

    As I said, this isn't intended as a slam or putdown - It's simple
    statement of fact. The need to ask "how do I..." about such a basic
    concept as determining whether a capacitor is good or bad is almost
    always an indicator of someone who is "in way over his head". Don't
    despair, though... Stupidity might be forever, but simple ignorance such
    as you're displaying can be easily cured with a dose of edgyookayshun :)

    Here's your first dose:
    Set up your meter for high ohms - 20K or thereabouts should be fine.
    Once you've gotten to the leads of the capacitor, use a screwdriver with
    a well-imsulated handle to short the leads of the capacitor together.
    Get yourself mentally prepared for a miniature lightning bolt to go off
    when the screwdriver makes contact. Eyeball the capacitor - Does it have
    a polarity marking? (Usually a plus or a minus sign, possibly a line of
    them, situated near one of the leads) If so, observe polarity - red/plus
    to plus, black/minus to either minus or the other lead from the
    capacitor - and touch the probes to the capacitor lead. If the cap isn't
    totally dead, you should see almost zero ohms at first, then rising to a
    higher value.

    If you see that, leave the probes in place for a few seconds, then
    remove them, switch your meter to read volts (20 will probably be
    overkill, but if you've got a higher range, start there, and work down
    until you get a reading) and touch the probes to the capacitor leads
    again. You should see an initial high value that slowly drops to zero.

    If either of these tests doesn't do what I told you would happen, then
    the cap is probably toast, and you'll need a new one. If they both work
    as described, put the lid back on. It's at least acting as a capacitor
    should, regardless of whether age has sent it "off value" or not, and it
    probably isn't the source of your problem.
  10. Guest

    thank you everyone so much! i got it running and ive never been
    happier! the problem was actualy not electrical. the piece that coverd
    the rotary end of the motor (i think thats right lol) was on way way
    way to tight (i didnt do it) after taking the whole thing apart and
    cleaning it its running fine. however, a graphite blade is broken and
    so the pump does not actualy pump any air :( its such a simple piece
    does anyone know where i could find a new one? thanks once again! oh
    and btw thanks for all the warnings about working with something i dont
    know anything about lol. i actualy did know that you can discharge a
    capacitor by setting a screw driver across the terminals but i hoped
    there was a safer way! havnt done that since i made my first tesla coil!
  11. John G

    John G Guest

    I am glad you said all that because I often get bagged for saying things
    like "You do not know enough to do what you want" when I am trying to
    save the OP from killing himself or others.
  12. Don Bruder

    Don Bruder Guest

    Yeah, I've seen that syndrome many times. I consider it for exactly what
    it's worth: The babblings of fools more interested in hearing the sound
    of their own imaginary "authority" on a topic they themselves don't know
    enough about to be saying "shit" about if they were standing there with
    a mouthful of it. The "politically correct" climate today is really
    conducive to "Oh, don't listen to that jerk saying you don't know

    Never mind that the querant has posed a question about a fundamental
    task that even the rankest qualified beginner knows either can't be done
    safely, or can't be done at all using the proposed methods.

    As I made a point of distinguishing, there's two classes of people:
    There's "stupid" (AKA "Just plain dumb"), and there's "ignorant" (AKA
    "Unknowing"). Stupid is incurable. You don't know, you can't know, you
    won't know, you make no effort to know - You're stupid, with every
    negative connotation the word can be loaded down with, and you deserve
    to die in agony from the results of a stupid deed. Ignorance is cured
    with incredible ease. You don't know, but you acknowledge that you
    don't, and seek assistance. You gain knowledge. You're no longer
    ignorant. Cured! Holy of holies, I'm cured! :)

    OP on this one struck me as ignorant, and was handled accordingly.
    Sounds like he might have actually learned something, too :)
  13. Rich Grise

    Rich Grise Guest

    A motor capacitor would be non-polar; they run on AC, you know. ;-)

  14. Rich Grise

    Rich Grise Guest

    A klixon is a thermal cutout switch. That's your motor overheating

    But, according to your other post, you got it going. Congrats!

    For the vane, try googling for vacuum pump parts, vane pumps, that sort
    of thing. You might have to make one, but from the vane pumps I've seen,
    that wouldn't be very hard.

    Good Luck!
  15. Rich Grise

    Rich Grise Guest

    Uh, actually, it's the other way around. The universal type doesn't need
    a capacitor - the induction type does.

  16. Lord Garth

    Lord Garth Guest

    Your right...sorry !!! You know, I just had an air compressor apart about
    two months ago. The centrifugal switch near the commutator was bad.

    The other compressor I had apart more recently was the one on my Ford A/C.
    All together, I spent about $120 to fix my A/C. A dealer wanted over $1000
    for the work. The break down was $80 for a clutchless rebuilt compressor
    $30 for 6 cans of r-134a. Tools were an A/C manifold and a vacuum pump.
    Various sockets and 2 hours. It'll freeze your tits off now!

    The failure analysis was the gasket that sealed the compressor failed and
    oil (but not the freon) left the system. Because there are valves on the
    is why I still had freon. The now un-lubricated compressor seized and some
    aluminum particles were in the expansion valve filter. The old compressor
    can be repaired and is amazingly simple.

    I'm ready for summer!
  17. Guest

    Look up nema receptacles and plugs on the net or go to an electrical
    supply house and see if they have a chart showing the many many
    different types of electrical cord outlets and plugs. There are special
    plugs for 120 volts that will not fit a normal household 120 volt

    It could also be a locking type plug...most applications where you are
    using a vacuum dont want anyone accidentally pulling the
    plug on the machine because you lose vacuum.
  18. Guest

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