speed control

Discussion in 'The Projects Forum' started by iowdave, Oct 10, 2014.

  1. iowdave

    Thread Starter New Member

    Oct 10, 2014
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    good afternoon hello all newbie here with a problem.. i have a 480 watt sander which i need to use a speed controller for a project im doing. i have wired a speed controller to it and it works but i need the sander to stop on the controller. as soon as i plug it in it starts running any guides please thank you
     
  2. alfacliff

    Well-Known Member

    Dec 13, 2013
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    turn off the speed controller unless you want the sander to run.
     
  3. MaxHeadRoom

    Expert

    Jul 18, 2013
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    If this is the typical Triac Universal motor controller there is usually a switch fitted integral to the speed Pot?
    If it does not have you could fit your own, or just an ordinary SP switch ahead of the controller?
    Max.
     
  4. iowdave

    Thread Starter New Member

    Oct 10, 2014
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    thank you very much for both your speedy replys electrics is a bit over my head is there a unit i could buy to solve this? i might not of explained it very good but i need the sander to start from 0 rpm if this is possible thank you
     
  5. MaxHeadRoom

    Expert

    Jul 18, 2013
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    There are the dimmer type power versions for the Universal motors that come with a switch, but when the switch is turned on it usually switches the motor to very low rpm, do you want actual zero rpm when the switch is turned on?
    It almost sounds like you want the same set up they have on treadmills where if you switch power on, the pot has to be returned to zero before the motor starts, but this would entail a slightly more sophisticated controller.
    Max.
     
  6. iowdave

    Thread Starter New Member

    Oct 10, 2014
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    max thank you yes thats just what i need zero when i switch on could you let me know which items i need if you dont mind thanks dave
     
  7. MaxHeadRoom

    Expert

    Jul 18, 2013
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    The T.M. controllers are a bit more sophisticated that the average simple Triac controller, I am not sure it would be worth incorporating the pot circuit into one of those.
    Do you have much experience building simple circuits?
    Not quite the same outcome, but one thing you could look at will the pot set zero speed when the turned to the off position and the switch jumpered out to see if it is a case of the pot causing the motor to run as it comes off the switch, if this works for you you could jumper the pot switch and fit a switch ahead of the unit, if you get my drift?
    Max.
     
  8. iowdave

    Thread Starter New Member

    Oct 10, 2014
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    thanks max im not an expert at ciruits far from it but il look into what you said and see if i can make it out.. appreciate your time cheers... dave
     
  9. floomdoggle

    Senior Member

    Sep 1, 2008
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    Sorry if I'm too far off topic here, but what are you using this variable speed sander for? I do a lot of sanding myself.
     
  10. iowdave

    Thread Starter New Member

    Oct 10, 2014
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    hi floomdoggle im doing a project where i need to make a shaker system and needed it to start from zero rpm.....so not a sanding project but i welcome everybody ... thanks
     
  11. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    Just know that as you slow a tool/motor like this down, the heat in the motor will be higher. The motor also drives the cooling fan and the fan won't move as much air at low speed.
     
  12. iowdave

    Thread Starter New Member

    Oct 10, 2014
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    hi shortbus and thanks for your input are u thinking id need to add a cooling fan for the motor ? cheers
     
  13. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    Maybe we should back-up and start from the beginning:) Just reread the post where you are making a 'shaker'. Is this sander a rotary or vibrating sander? If a rotary/motor driven sander an extra fan probably will be needed if running very slow. Try it and see. Not sure if a vibrating type sander can be slowed down. They work on the 60Hz cycle of the power line.
     
  14. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Depends on the motor technology, induction or Universal, the OP mentions running with possibly a Triac controller, induction do not normally like Triac controllers if Cap start/run motor.
    Universal are OK.
    Also if 1ph induction, you cannot go down to zero rpm
    Max.
     
  15. iowdave

    Thread Starter New Member

    Oct 10, 2014
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    hi shortbus and max and thanks for your replys im starting to understand it more now so cheers
     
  16. iowdave

    Thread Starter New Member

    Oct 10, 2014
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    hello all again trying to get my head around this electrics but having no luck and struggling to understand ..im trying to get this sander to start from zero rpm and these are what im trying with could somebody be kind enough to tell me how i need to wire it and what i need .......if its possible to do it....
     
  17. MaxHeadRoom

    Expert

    Jul 18, 2013
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    That is a Universal motor according to the RPM.
    It looks like one of the Hong Kong speed controllers off ebay?
    Have you tried it yet and this is the one that does not go down to zero?
    I would be interested in knowing the number of the large IC on the heat sink.
    It could be Triac, or PWM control, although the PWM usually have a 555 IC on the board.
    Max.
     
  18. iowdave

    Thread Starter New Member

    Oct 10, 2014
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    hello again max and appreciate your reply it is just a cheap one from ebay and yes it wont slow it down but speeds up no problem ..the number on the heatsink is BTA76 600B if that looks rite to you .. cheers dave
     
  19. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Appears to be a Triac, what does the pot do? did you try adjusting it, I imagine if it one of the ebay cheapies there were no instructions?
    I see one of the ebay ads mention voltage control from 50 to 250, also mentions SCR, but I think they mistakenly mentioned bi-directional SCR instead of triac.
    Max.
     
  20. iowdave

    Thread Starter New Member

    Oct 10, 2014
    17
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    cheers max .. no instructions i was going to ask you about the little screw does that do adjustments to slow down? would you have any ideas how i could do this with another device? im quite happy to buy anything that would work ok.. cheers
     
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