Page 1 of 2 12 LastLast
Results 1 to 10 of 20

Thread: O.T. "Universal" Motors DC Voltage Question

  1. #1
    Join Date
    Dec 2007
    Location
    Keller, Texas
    Posts
    421

    Default O.T. "Universal" Motors DC Voltage Question

    I have a winch that was salvaged from a truck mounted crane. I bought it mainly because it was advertised as being 115 volt (plus, it looked pretty stout and the price was right).
    The motor data plate says 115 volt, DC/60 cycle. It seems to operate just fine on standard house current (17 amps at full load). It has a NEMA 10-20 inlet that has the centerline blade wired as ground.
    I'm sure it will be nice having an A.C. winch around the shop, but it sure would be handy if I could use this same winch on the road using DC power, but I am unfamiliar with "universal" motors.
    What is the rule for DC voltage operation of universal motors? How low can you go?
    The motor plate says 115.



  2. #2
    Join Date
    Jan 2004
    Location
    Independent principality of Sinquefieldia (formerly Missouri)
    Posts
    17,371

    Default

    basically, it is 115VAC or 115V DC.

    Will it "work" with less? yes..... but it will be wimpy and useless with a lot less..... I'd expect it to barely turn decently at 12V DC, assuming that is your real question.....

    Dunno how low you can go..... probably 1/3 of nominal for reasonable performance.

  3. #3
    Join Date
    Dec 2007
    Location
    Keller, Texas
    Posts
    421

    Default

    ...so, ten truck batteries in series and I'm good to go eh?

    Is there a risk of damaging the motor by using too low a DC voltage?
    Last edited by dfw5914; 05-31-2012 at 01:19 AM.

  4. #4

    Default

    Quote Originally Posted by dfw5914
    Is there a risk of damaging the motor by using too low a DC voltage?

    Dot as long as it doesn't sit stalled under power.
    Craftsman 101.07403
    Grizzly G0704
    4x6 Bandsaw

  5. #5
    Join Date
    Apr 2009
    Location
    Ashburton, near Christchurch New Zealand
    Posts
    5,100

    Default

    If you can mount another alternator on your truck and run it without a regulator you will have high voltage DC available to drive your winch. Maybe?

    [later] There is some info here http://www.aeroelectric.com/articles...er_Voltage.pdf
    Last edited by The Artful Bodger; 05-31-2012 at 06:05 AM.

  6. #6
    Join Date
    Aug 2002
    Location
    Albuquerque
    Posts
    2,219

    Default

    Quote Originally Posted by The Artful Bodger
    If you can mount another alternator on your truck and run it without a regulator you will have high voltage DC available to drive your winch. Maybe?
    Until you blow the diodes. The idea does work well but the pressed in
    diodes are often not up the un-regulated out put voltage. Just change
    them. I ran drills and saws on the one in my Subaru back in the '60s.
    ...lew...

  7. #7
    Join Date
    Apr 2011
    Location
    SW Michigan
    Posts
    4,000

    Default

    Use an inverter. I have a 12,000 watt & an 18,000 watt inverter both 12V in & 120V out. Woek greay! Or pick up a small generator 120V.
    "Patriotism is supporting your country all the time, and your government when it deserves it". Mark Twain

  8. #8
    Join Date
    Sep 2001
    Location
    Birmingham, AL
    Posts
    1,062

    Default

    12 kw inverter at 12 volts, interesting to see the batteries for that, even
    more interesting to see the input power connex for ~1300 amps in (assuming
    90% efficiency) and the power cable.
    Steve

  9. #9
    Join Date
    Aug 2002
    Location
    Albuquerque
    Posts
    2,219

    Default

    Quote Originally Posted by sch
    12 kw inverter at 12 volts, interesting to see the batteries for that, even
    more interesting to see the input power connex for ~1300 amps in (assuming
    90% efficiency) and the power cable.
    I was going to comment on that also. :-) Even more interesting for
    18000 Watts. :-) What size wire is used to hook it to those batteries too.? :-)
    ...Lew...

  10. #10
    Join Date
    Jan 2003
    Location
    Chilliwack, B.C.
    Posts
    9,587

    Default

    I have to question the use of it on a truck-mounted crane. What power source ran it? I guess I'm suspecting that the truck had a generator or alternator that put out that kind of voltage. It makes sense in one aspect- you wouldn't need to handle 200 amps of dc and use heavy wire to run it. Possibly the truck had a generator on the back using its own engine, possibly also it was a welder/generator.

    In any event, if you feed it less than about 90 volts, it's going to be nearly useless unless you keep the loading very light. Kind of pointless, as you would then be better off with a much smaller winch package.

    If you have lots of room under the hood and don't mind adding another alternator, as others have said you can set it up to run unregulated and it will produce 100 volts or so- my friend used to use a setup like that, though his was a conversion switch to use the existing alternator. Best if the regulator is outboard- then you can use higher voltage diodes and heat-sink them separately from the alternator housing.

    Maybe it would make more sense for you to replace your existing alternator with one that is somewhat larger, and can be set up the same way- 12v system charging in normal use, then switch over for higher voltage use. My friend ran his skilsaw, etc from his, when he was too far from domestic electricity.

Posting Permissions

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