Page 1 of 2 12 LastLast
Results 1 to 15 of 16
  1. #1
    Join Date
    May 2011
    Location
    Murray Bridge S Aust.
    Age
    71
    Posts
    5,942

    Default Sewing machine variable controller

    I'm in a position where I need to make a miniature welding rotator. Thinking of using a sewing machine motor to power it, but would need a variable switch to get the RPM right, would a fan control switch or light dimmer switch be sufficient to do it. The drive will be by toothed belt, so as not to interfere with the motor side of things
    It'll be running a 4" 3jaw chuck and welding a bolt on the end of 15NB pipe, have several hundred of them to do, not all at once, thank God!!!!!
    Kryn
    To grow old is mandatory, growing up is optional.

  2. #2
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
    Posts
    6,439

    Default

    Hi Kryn,

    Here you go !

    motor-speed-regulator-schematic.gif

    I know it says 230 VAC, it will happily work on 110 as well should you need it to.
    C1, C2, R1 and L1 are interference suppression components. The circuit will work just as well without them.
    If you get noise on your radio when running then include those components.
    Best Regards:
    Baron J.

  3. #3
    BobL is offline Member: Blue and white apron brigade
    Join Date
    Feb 2006
    Location
    Perth
    Posts
    7,182

    Default

    What sort of motor is it motor and what RPM do you require?

  4. #4
    Join Date
    Oct 2011
    Location
    Norwood-ish, Adelaide
    Age
    59
    Posts
    6,541

    Default

    My thoughts too. I would have thought for welding you would want something around 60rpm perhaps +60, -30rpm. A sewing machine motor is not going to do that straight out of the box. If the only thing you are doing are these bolts, perhaps a pin on a base plate and a socket on top of that would be enough to do the job (rotate by hand - use an old steering wheel, pulley or something similar)

    Michael

  5. #5
    BobL is offline Member: Blue and white apron brigade
    Join Date
    Feb 2006
    Location
    Perth
    Posts
    7,182

    Default

    Sewing machine motors are typically in the 6 to 10k rpm range so to get 30rpm requires at least 200:1 reduction. Doing this electrically is a big ask so you will need some mechanical reduction before hand. Even if you can get a 10:1 mechanical reduction that still leaves a 20:1 reduction electrically which is 95% speed reduction where the motor may have little or no torque left to drive any load.

    If you wanted to pursue this I'd be looking at a 12/24V DC motor with a full reduction gear box as they go for about $20 on ebay..

  6. #6
    Join Date
    Sep 2010
    Location
    Lebrina
    Posts
    1,910

    Default

    Do you have access to a straight line oxy cutter? They make brilliant rotators as all the work has been done for you and you just need to mount a chuck or plate on the drive wheel.

  7. #7
    Join Date
    Oct 2015
    Location
    melbourne
    Posts
    473

    Default

    Hmmm

    Are we talking domestic motor or industrial?
    A domestic sewing machine foot controller lets you sew really slowly.. Down to a single stitch at a time. And the old ones are just a variable resistance.

    Sewing machines don't have a massive reduction inside. A universal motor does have good torque at low speed.

    But your weld positioner will probably have a lot more mass than a sewing machine, so you should aim for as much reduction as you can arrange.







    Russ

  8. #8
    Join Date
    May 2011
    Location
    Murray Bridge S Aust.
    Age
    71
    Posts
    5,942

    Default

    Quote Originally Posted by BaronJ View Post
    Hi Kryn,

    Here you go !

    motor-speed-regulator-schematic.gif

    I know it says 230 VAC, it will happily work on 110 as well should you need it to.
    C1, C2, R1 and L1 are interference suppression components. The circuit will work just as well without them.
    If you get noise on your radio when running then include those components.
    Thanks for that John, only problem is that, to me it's just squiggly lines and black triangles.
    Electronics ain't my field/interests.
    The reason I mentioned using a sewing machine motor, is that I have several of them, didn't think that they ran that fast though.
    Oh Well, back to the drawing board, might look at microwave motors, as they run about 3 rpm, which should be enough.
    Thanks everyone for their comments.
    Kryn
    To grow old is mandatory, growing up is optional.

  9. #9
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
    Posts
    6,439

    Default

    Hi Kryn,

    OK point taken I won't suggest a light bulb dimmer switch then, which would also work.

    You could look at an oven rotisserie motor ! I don't think you will get anyway near enough torque from a microwave turntable motor.
    Best Regards:
    Baron J.

  10. #10
    Join Date
    Jun 2010
    Location
    Canberra
    Posts
    1,322

    Default

    What about an old cordless drill with a 2 speed gearbox? In low gear and with the trigger only just depressed, they go pretty slow. You could also drop the supply voltage to go even slower.

  11. #11
    Join Date
    May 2011
    Location
    Murray Bridge S Aust.
    Age
    71
    Posts
    5,942

    Default

    Thanks for that Rusty, as I mentioned to John, electrics is not a field that I'm familiar with nowadays, so I'd like to stay away from voltage reducing equipment.
    Was hoping to do a plug and play sort of thing.
    10 years ago I wired up my shed, can't remember how to do a light switch now.
    Kryn
    To grow old is mandatory, growing up is optional.

  12. #12
    Join Date
    Oct 2011
    Location
    Norwood-ish, Adelaide
    Age
    59
    Posts
    6,541

    Default

    If you had a lathe, you could chuck up a broomstick (insulator) and then support the free end in a bush. Cover the bed, attach the chuck to the end of the broomstick and put it on a slow speed and you might just be able to do it.

    Failing that, I do have surplus spankers 20:1 gearbox here.

    Michael

  13. #13
    Join Date
    May 2011
    Location
    Murray Bridge S Aust.
    Age
    71
    Posts
    5,942

    Default

    Thanks for the offer, Michael. How big is it, shaft sizes, etc.and how much do you want for it?
    Kryn
    To grow old is mandatory, growing up is optional.

  14. #14
    Join Date
    Aug 2006
    Location
    Melbourne
    Posts
    1,105

    Default

    Quote Originally Posted by Karl Robbers View Post
    Do you have access to a straight line oxy cutter? They make brilliant rotators as all the work has been done for you and you just need to mount a chuck or plate on the drive wheel.
    That is actually a really good idea Karl, never thought about that before.

  15. #15
    Join Date
    May 2011
    Location
    Murray Bridge S Aust.
    Age
    71
    Posts
    5,942

    Default

    Thanks for the idea Karl.
    I don't have access to one but looked on gumtree and found one at a respectable price, no nozzle or track, not that I need them ATM.
    Waiting on a reply from the seller. They're not a cheap item!!!!
    Kryn
    To grow old is mandatory, growing up is optional.

Page 1 of 2 12 LastLast

Similar Threads

  1. Motor Speed Controller
    By barkersegg in forum ELECTRICALS
    Replies: 15
    Last Post: 23rd Aug 2018, 08:49 AM
  2. Mill motor controller !
    By BaronJ in forum METALWORK GENERAL
    Replies: 4
    Last Post: 14th Jul 2017, 01:51 AM
  3. Electromagnetic chuck controller
    By .RC. in forum METALWORK PROJECTS
    Replies: 39
    Last Post: 15th Dec 2016, 11:39 AM
  4. Variable speed motor and controller
    By Jim Ferrous in forum METALWORK GENERAL
    Replies: 5
    Last Post: 24th Sep 2013, 03:03 PM
  5. cheap foot TIG controller
    By WelderMick in forum WELDING
    Replies: 2
    Last Post: 17th Jan 2011, 01:33 PM

Posting Permissions

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