Using a wall mounter dimmer to drive a bigger load than it is rated for

Discussion in 'The Projects Forum' started by garch, Feb 3, 2010.

  1. garch

    Thread Starter Member

    Aug 23, 2008
    24
    0
    Hi,

    I have existing wall mounted (no neutral) triac dimmers. They can drive up to 300W (@ 230VAC). I would like to use them to drive a much larger resistive load. I have enclosed a circuit diagram that uses the 300W dimmers as a driver for a seperate TRIAC with a higher power rating.

    Would this work?

    Thanks
     
  2. MikeML

    AAC Fanatic!

    Oct 2, 2009
    5,450
    1,066
    probably not! The original dimmer needs a minimum load that is much lower than 2K.
     
  3. t06afre

    AAC Fanatic!

    May 11, 2009
    5,939
    1,222
    Get a approved dimmer that can handle more current. Tampering with such equipment is not recommended.
     
  4. garch

    Thread Starter Member

    Aug 23, 2008
    24
    0
    Getting an approved dimmer is not an option. These are ACT EU frequency zwave dimmers. They only come in one rating. I have ten in my house and they cost 80 dollars a piece.

    Hence my question.
     
  5. garch

    Thread Starter Member

    Aug 23, 2008
    24
    0
    Updated diagram enclosed. Replaced 2K load resistor with 2 x 1K, 50W (in parallel) resistor load.
     
  6. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    Many restaurants are throwing away high power dimmers because they are switching to efficient compact fluorescent light bulbs that cannot be dimmed.

    If you still heat your home with wasteful incandescent bulbs then pickup a powerful dimmer from a restaurant.
     
  7. garch

    Thread Starter Member

    Aug 23, 2008
    24
    0
    Thanks,

    But I say again, these are ZWave dimmers that I already have and are integrated into the house automation system.

    Net net they save power because:

    1) They are auomatically dimmed to match ambient light levels (by the computer)
    2) The lights turn off when you leave the room
    3) Part of the lighting array uses proper "dimmable" cfl's anyway where possible, with a resistive load (mains halogens) included to allow the TRIAC to operate.
    4.) Part of the lighting array uses German made ultra high efficiency fluorescent linears (A+ rated) that are dimmed via an intelligent dimmable ballast.

    I did the Carbon Calcs for my home and this method is more efficient than replacing every light with a simple CFL. Turning CFLs on and off continually is not very efficient.

    and before you ask...

    The automation computer is totally solid-state and purpose built and uses very little power. It uses about 30W of power at full gallop.

    I want to up-rate the dimmers driving capacity to increase their reliability. The triacs seem to fatigue after about one year, so wanted to implement a master-slave config to buffer them. It is what microwave oven designers do to increase the reliability of the driver triacs that modulate the massive inductor that drives the magnatron.

    p.s. I did do a BSc (hons) in Electrical Enginnering 20 years ago, but am a little rusty on the power electronics side.
     
  8. Audioguru

    New Member

    Dec 20, 2007
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    896
    You have dimmers all over your place.
     
  9. garch

    Thread Starter Member

    Aug 23, 2008
    24
    0
    Yes, 20 dimming modules in total.
     
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