12v heating element dimmer

Discussion in 'General Electronics Discussion' started by Andi lycett, Feb 17, 2017.

  1. Andi lycett

    Andi lycett

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    Hello hive mind,

    I have an electric towel warmer that is 12v and when measured without a dimmer inline is drawing 3amps.

    The warmer is a little to hot and I would like to introduce a dimmer onto it, I have a 240v dimmable transformer and added a normal 240v household lighting dimmer before that. But now I keep blowing the transformer, I also tried a 12v dimmer the other side of the transformer and it was if the dimmer wasn't in line it didn't do anything.

    Does anyone know what I am doing wrong ? Sorry for the vague explanation

    Andi
     
    Andi lycett, Feb 17, 2017
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  2. Andi lycett

    duke37

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    Please give details of what you have and how they are connected. Pictures are very useful.
    12V at 3A is very small for a heater.
    230V at 3A is very large so not likely to be what you have.
    Phase angle dimmers can have problems feeding transformers.
     
    duke37, Feb 17, 2017
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  3. Andi lycett

    Minder

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    I made a hot wire foam cutter using a Triac controller on the secondary, although many have used a dimmer on the primary, Did you put the dimmer together yourself or an off the shelf version?
    M.
     
    Minder, Feb 17, 2017
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  4. Andi lycett

    Andi lycett

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    I just used a standard lighting dimmer that you would use in the house.

    Do you have a link to the triac ?

    Cheers

    Andi
     
    Andi lycett, Feb 17, 2017
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  5. Andi lycett

    Andi lycett

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  6. Andi lycett

    Minder

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    If the towel warmer just involves a element only, then one avenue would be to look for a Wall Wart that is either 12vDC at least 5amp and obtain one of the $5.00 PWM controllers off ebay.
    If the wall wart is ~9v AC then you could put a bridge with a 470uf cap on the output for a PWM controller use.
    That transformer you show does not appear suitable for the application.
    This is as long as the warmer does not have any inductive devices in it.
    M.
     
    Minder, Feb 17, 2017
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  7. Andi lycett

    duke37

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    In a bathroom there are strict regulations about the wiring. As far as I am aware, the only device which is legal is a shaver socket which has an isolating transformer. Lights must be switched with a cord. Others will know the regulations better than me.
     
    duke37, Feb 18, 2017
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  8. Andi lycett

    Andi lycett

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    Sorry for being a simpleton, do you have a link to the pwm controller, the only one I could find in the UK is £50 and there's lots of types
     
    Andi lycett, Feb 18, 2017
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