Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Speed controller with a heating element?

  1. Jan 2, 2012 #1
    I use a popcorn popper to roast coffee beans. I'd like to be able to vary the heat of the heating element (as inexpensively as possible). My thought is to connect into the internal wiring of the popper to the heating element and run a wire out to connect to some type of external controller. MLCS has a router speed controller that I'm considering; my hesitancy is that this controller uses feedback from the controlled "router" to vary the voltage to the load to maintain consistent speed.

    Any thoughts or suggestions? thanks
     
  2. jcsd
  3. Jan 2, 2012 #2

    jim hardy

    User Avatar
    Science Advisor
    Gold Member
    2016 Award

    maybe a lamp dimmer? The cheapies will handle 600 watts.
     
  4. Jan 3, 2012 #3
    Thanks Jim, but I need at least 1200 watts, possibly 1400 at some point. I saw an entry in another thread about using a electric stove heating element control switch. I might give that a try depending on other replys I may get here.
     
  5. Jan 3, 2012 #4

    sophiecentaur

    User Avatar
    Science Advisor
    Gold Member

    Time was when you could buy just what you need in the form of a plug-in Drill Speed Controller. Nowadays, they seem to be included inside devices. I need the same thing for reducing the speed on my angle grinder so that I can use it as a small diameter, slow speed polisher. No luck so far.

    If you were to work out what power you need, then you could just insert an appropriate heater element in series with the popper element (say an electric fire or water heater). But this wouldn't really be good to run in your kitchen haha.

    Do they still make 'simmerstat' controls'? All electric cookers used them at one time and they were, basically, a thermal interruptor, with a duty cycle of a few seconds. What's used in IR Hob controls these days? Could be just what you need if you could mount it in a suitable box.
     
  6. Jan 3, 2012 #5
    My goal is to be able to vary the voltage to the 1200 watt heating element of the popper during different phases of roasting the coffee beans, with all the beans roasted as evenly as possible as they move past the vents (side vent poppers rotate the beans, but at any given moment, only a fraction of the beans are receiving the full heat transfer). Is a simmerstat and a electric stove "burner" control the same thing?
     
  7. Jan 3, 2012 #6

    jim hardy

    User Avatar
    Science Advisor
    Gold Member
    2016 Award

    Last edited by a moderator: May 5, 2017
  8. Jan 4, 2012 #7
    I've decided to buy a single burner hot plate and tap into the control knob. May be weeks before I get the part, wire it, wire the popper, and try it. If anyone is curious, I think I may post my result with that experiment here.

    Cheers, and Happy New Year
     
  9. Jan 4, 2012 #8
    Heaters are slow to react to power changes. Typically, I'd design in a zero-crossing solid state relay. 20 amp versions are readily available from Digikey. They are typically switched off / on via a 5 volt signal. A 5 volt wall wart with a 555 timer can give you the pulse you need to set it to a given duty cycle.
    Alternately, you might wish to purchase an integrated heater control. Watlow is the most popular brand. You can get them to run off of a variety of voltages and use a variety of sensors for temperature feedback.
     
  10. Apr 11, 2012 #9
    According to me, this is done entirely at your own risk. Because you are using a domestic appliance in a manner for which it was not designed and also you are dealing with high temperatures and combustible materials. So, supervise the process at all times. I would suggest you to never use an extension cord, unless it has a ground pin as well. The can will get hot during roasting! Use non epoxy method, you will need to use an oven mitt or a pair of pliers move or reposition it.

    http://coffeebeanswarehouse.com/ [Broken]
     
    Last edited by a moderator: May 5, 2017
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Speed controller with a heating element?
  1. Heating elements (Replies: 12)

  2. Heating Element (Replies: 3)

Loading...