Power control ... ?!

Discussion in 'The Projects Forum' started by odintheterrible, Jul 16, 2014.

  1. odintheterrible

    Thread Starter New Member

    Jun 16, 2010
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    Greetings one and all,

    Up until recently I had a largish workshop vacuum that I used in a dust collection circuit in my home workshop.
    In essence it had a 13amp power socket in the lid into which you plugged, say, a table saw (or whatever) then when the power tool was switched on, it would automatically start up the vacuum to draw the sawdust from the unit into the collection bin.
    Alas, the vacuum finally expired after many years excellent service and I can't find a suitable replacement with this sort of controlled power take-off.
    So, do any of you knowledgeable guys n gals have any idea if it's possible to build a suitable stand-alone circuit that will fulfill this function ???
    I've looked long and hard and can't find any references to a suitable circuit which can be built relatively cheaply :-(
    Many thanks in advance.
     
  2. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    Just need a relay with a coil/contact rating suitable for the voltage. (I'll assume 120VAC)

    Or just plug both into a suitable power strip.. switch on the power strip and voila.. any device plugged into it will turn on
     
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  3. inwo

    Well-Known Member

    Nov 7, 2013
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    If you have a local HVAC guy, get a humidifier current relay and a fan center.

    The fan center is a 24V transformer/ relay combination that should handle the dust collector current. The current relay has a few heavy turns that will sense tool power and pull relay in.

    Did original have delay built in?

    Here is a solid state version.

    Or one of these. http://www.woodcraft.com/product/2080165/28298/ivac-automated-shop-vacuum-switch.aspx
     
    Last edited: Jul 16, 2014
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  4. KMoffett

    AAC Fanatic!

    Dec 19, 2007
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    Metalmann and odintheterrible like this.
  5. odintheterrible

    Thread Starter New Member

    Jun 16, 2010
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    Many thanks for taking the time and trouble to reply ... but it's 230VAC ... I forgot to mention that I'm U.K. based

     
  6. odintheterrible

    Thread Starter New Member

    Jun 16, 2010
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    Many thanks for sharing this valuable info .... but as I'm U.K. based with a 230VAC supply, would it be possible to modify it to get it to work on UK mains voltage ??? ... and if so, how would I achieve this ??
    Thanks

     
  7. KMoffett

    AAC Fanatic!

    Dec 19, 2007
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    Sure. Just select T1 in the sensor circuit that is 230vac 50Hz primary and 18VAC/ct secondary. Secondary current requirements are very low...maybe >100mA. The 12VDC in the timer circuit was a gutted wall wart. You could probably do the same for the sensor circuit. I like gutting wall warts for low voltage power supplies to put inside line-voltage devices. The connection between the two circuits is a 2-wire cable running across the shop with 1/8" phone plugs on each end. For the timer circuit you would need to select an SSR that is rated for 230VAC inductive load.

    It's been running daily for quite a few years on two different saws. First a Delta contractor saw, and now on a Saw-Stop

    Ken

    Now, I'd probably do the sense and timer with a 08M2 PICAXE microcontroller.
     
    Last edited: Jul 16, 2014
  8. odintheterrible

    Thread Starter New Member

    Jun 16, 2010
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    Greetings,

    Many thanks for taking the time and trouble to respond in such a helpful manner ... it's a dying quality alas these days.

    I'm not a continuous dabbler and experimenter, more an as needs be sort of doer so I'm not terribly of the moment , so to speak, when it comes to stuff like this but I'll give the schematics a good look over at the week-end and see if they aren't going to be too challenging for a simple soul like myself LOL

    Many thanks once more.
     
  9. inwo

    Well-Known Member

    Nov 7, 2013
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    Here's simple, but no timer.
     
  10. KMoffett

    AAC Fanatic!

    Dec 19, 2007
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    An off the shelf...with caveats for UK:
    https://www.bctint.com/ecommerce.action
    This is the one that appeared after I posted my concept/design.

    Ken
     
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