Loading ...
Sorry, an error occurred while loading the content.
 

Heating Element Controller

Expand Messages
  • Mark
    I have both the Lutron 1500W and the Sutronics. Both work. Both are zero switching (turn power off as AC waveform crosses through zero to minimize RF
    Message 1 of 12 , Feb 2, 2005
      I have both the Lutron 1500W and the Sutronics. Both work. Both
      are "zero switching" (turn power off as AC waveform crosses through
      zero to minimize RF noise). Sutronics unit runs marginally cooler,
      but I installed (duct tape) a small 110VAC fan on both units anyway.

      One odd point. The dial on my Lutron unit is not linear. Full
      power is at available when the dial is at 3:00 o'clock, but the dial
      will continue around to 5:00. About the same at the extreme lower
      power range. I connected a true RMS wattmeter to the Lutron to set
      an output power level.

      Another note - the resistance of my heating elements (internal on
      the water heater stripper still, hot plate on the finishing still)
      decrease as they heat up. Then more current flows at the same
      applied voltage. The wattmeter shows that the power increases. Not
      much - about 5%.

      Mark
    • peter_vcb
      as the element wires heat up the restistance in them lessens and so more power is noted at the same voltage Power=(VoltagexVoltage)/restistance ... dial ...
      Message 2 of 12 , Feb 3, 2005
        as the element wires heat up the restistance in them lessens and so
        more power is noted at the same voltage
        Power=(VoltagexVoltage)/restistance

        --- In Distillers@yahoogroups.com, "Mark" <markgofast@h...> wrote:
        >
        > I have both the Lutron 1500W and the Sutronics. Both work. Both
        > are "zero switching" (turn power off as AC waveform crosses through
        > zero to minimize RF noise). Sutronics unit runs marginally cooler,
        > but I installed (duct tape) a small 110VAC fan on both units anyway.
        >
        > One odd point. The dial on my Lutron unit is not linear. Full
        > power is at available when the dial is at 3:00 o'clock, but the
        dial
        > will continue around to 5:00. About the same at the extreme lower
        > power range. I connected a true RMS wattmeter to the Lutron to set
        > an output power level.
        >
        > Another note - the resistance of my heating elements (internal on
        > the water heater stripper still, hot plate on the finishing still)
        > decrease as they heat up. Then more current flows at the same
        > applied voltage. The wattmeter shows that the power increases.
        Not
        > much - about 5%.
        >
        > Mark
      • Mike Nixon
        peter_vcb wrote: Subject: [Distillers] Re: Heating Element Controller as the element wires heat up the restistance in them lessens and so more power is noted
        Message 3 of 12 , Feb 3, 2005
          peter_vcb wrote:
          Subject: [Distillers] Re: Heating Element Controller

          as the element wires heat up the restistance in them lessens and so
          more power is noted at the same voltage
          Power=(VoltagexVoltage)/restistance
          =====================
          Sorry, but the reverse is true ... the resistance of metals increases with
          temperature.
          If resistance decreased with increasing temperature, then you would always
          get a runaway blowout, for as the element heats up then the resistance gets
          less, so the power dissipated gets more, so the element heats up further, so
          the resistance gets less, so etc etc etc .
          It's the fact that the resistance increases with increasing temperature that
          prevents such runaway.

          Back to the drawing board guys! :-))

          All the best,
          Mike N
        • Mark
          Mike: That s what I think - or thought? But when I measure (using an o scope) the current and the voltage, I see that the resistance of the water heater
          Message 4 of 12 , Feb 3, 2005
            Mike: That's what I think - or thought? But when I measure (using
            an o'scope) the current and the voltage, I see that the resistance
            of the water heater internal element drops from 16.5 ohms to around
            15.8 ohms after it's been running for awhile - but it stops dropping.

            One thought, it could be that the circuit is seeing some inductance
            as it heats up and I'm actually seeing the results of V leading I.

            My post missed the point I was trying to make - that I can't just
            set power and walk away. It needs to be adjusted a bit during the
            heat up phase.

            --- In Distillers@yahoogroups.com, "Mike Nixon" <mike@s...> wrote:
            > peter_vcb wrote:
            > Subject: [Distillers] Re: Heating Element Controller
            >
            > as the element wires heat up the restistance in them lessens and so
            > more power is noted at the same voltage
            > Power=(VoltagexVoltage)/restistance
            > =====================
            > Sorry, but the reverse is true ... the resistance of metals
            increases with
            > temperature.
            > If resistance decreased with increasing temperature, then you
            would always
            > get a runaway blowout, for as the element heats up then the
            resistance gets
            > less, so the power dissipated gets more, so the element heats up
            further, so
            > the resistance gets less, so etc etc etc .
            > It's the fact that the resistance increases with increasing
            temperature that
            > prevents such runaway.
            >
            > Back to the drawing board guys! :-))
            >
            > All the best,
            > Mike N
          • Mike Nixon
            Mark wrote: Subject: [Distillers] Re: Heating Element Controller Mike: That s what I think - or thought? But when I measure (using an o scope) the current
            Message 5 of 12 , Feb 3, 2005
              Mark wrote:
              Subject: [Distillers] Re: Heating Element Controller

              Mike: That's what I think - or thought? But when I measure (using
              an o'scope) the current and the voltage, I see that the resistance
              of the water heater internal element drops from 16.5 ohms to around
              15.8 ohms after it's been running for awhile - but it stops dropping.

              One thought, it could be that the circuit is seeing some inductance
              as it heats up and I'm actually seeing the results of V leading I.

              My post missed the point I was trying to make - that I can't just
              set power and walk away. It needs to be adjusted a bit during the
              heat up phase.
              ====================
              Beats me Mark! You should not be seeing any significant reactance in a
              resistive circuit like a heater element.
              Silly question perhaps, but are you reading that scope the right way up? I
              would find an increase of 0.7 ohm quite normal as an element heats up ...
              around 4% for a nomimally rated 240V 3.5kW element (if my guesses at your
              voltage and element are right). What it boils down to (sorry!) is a
              variation of around 150W. Is your still so sensitive that this will make
              any significant difference? What is so critical anyway during the heat up
              phase?? Will Elvis ever live again??? Answers to these, and other crucial
              questions, will all be revealed in due time :-))

              All the best,
              Mike N
            • Lindsay Williams
              Errr, it is the other way round. Resistance increases with heat. It would be rather interesting if it was your way. Heat=less resistance, less resistance=more
              Message 6 of 12 , Feb 3, 2005
                Errr, it is the other way round. Resistance increases with heat. It
                would be rather interesting if it was your way. Heat=less resistance,
                less resistance=more current, more current=more heat, more heat= .....

                Cheers,
                Lindsay.

                --- In Distillers@yahoogroups.com, "peter_vcb" <viciousblackout@y...>
                wrote:
                >
                > as the element wires heat up the restistance in them lessens and so
                > more power is noted at the same voltage
                > Power=(VoltagexVoltage)/restistance
                >
              • Mark
                Scope used a 0.25 ohm shunt to look at current on a 750W / 115VAC / 6.5A heater element circuit. The waveform from the power controllers is an ugly sine wave,
                Message 7 of 12 , Feb 3, 2005
                  Scope used a 0.25 ohm shunt to look at current on a 750W / 115VAC /
                  6.5A heater element circuit. The waveform from the power
                  controllers is an ugly sine wave, but enough I could scale and
                  measure each trace. Cheap scope, one channel - so I couldn't see
                  both I and V at the same time. A phase change caused by either the
                  element or the controller would easily cause my error.

                  (translation .... "oops. now I'm not so sure")

                  The power setting on the stripping still (16 gal wash @ 15%, 750W)
                  is not an issue. It's floored all the time anyway. But on the
                  finishing still (3.0 gal @ 80ish abv, 1100W max), I tend to run the
                  first 4 hours at a slow drawoff (150ml/hr) with a lot of power and a
                  lot of reflux. A 150W power change is more than a 10% variation, so
                  at least initially it's important to me.

                  > ====================
                  > Beats me Mark! You should not be seeing any significant reactance
                  in a
                  > resistive circuit like a heater element.
                  > Silly question perhaps, but are you reading that scope the right
                  way up? I
                  > would find an increase of 0.7 ohm quite normal as an element heats
                  up ...
                  > around 4% for a nomimally rated 240V 3.5kW element (if my guesses
                  at your
                  > voltage and element are right). What it boils down to (sorry!) is
                  a
                  > variation of around 150W. Is your still so sensitive that this
                  will make
                  > any significant difference? What is so critical anyway during the
                  heat up
                  > phase?? Will Elvis ever live again??? Answers to these, and
                  other crucial
                  > questions, will all be revealed in due time :-))
                  >
                  > All the best,
                  > Mike N
                • Mike Nixon
                  Mark wrote: Subject: [Distillers] Re: Heating Element Controller Scope used a 0.25 ohm shunt to look at current on a 750W / 115VAC / 6.5A heater element
                  Message 8 of 12 , Feb 4, 2005
                    Mark wrote:
                    Subject: [Distillers] Re: Heating Element Controller

                    Scope used a 0.25 ohm shunt to look at current on a 750W / 115VAC /
                    6.5A heater element circuit. The waveform from the power
                    controllers is an ugly sine wave, but enough I could scale and
                    measure each trace. Cheap scope, one channel - so I couldn't see
                    both I and V at the same time. A phase change caused by either the
                    element or the controller would easily cause my error.

                    (translation .... "oops. now I'm not so sure")

                    The power setting on the stripping still (16 gal wash @ 15%, 750W)
                    is not an issue. It's floored all the time anyway. But on the
                    finishing still (3.0 gal @ 80ish abv, 1100W max), I tend to run the
                    first 4 hours at a slow drawoff (150ml/hr) with a lot of power and a
                    lot of reflux. A 150W power change is more than a 10% variation, so
                    at least initially it's important to me.
                    ====================
                    Hi Mark,

                    You've got me beat on this one. I first assumed (bad) that you were running
                    a 3.5kW element off 240VAC as the other option indicated a 750W/115VAC
                    element, and not many use or can get those.

                    So, 750W / 115VAC / 6.5A heater element has a resistance of either 17.7 ohm
                    or 17.6 ohm depending on whether you believe the current or the wattage
                    rating. Let's just call it 17.65 and split the difference. You measured
                    16.5 ohm cold, corresponding to a rated wattage of 801.5W, and when the
                    thing was hot you measured 15.8 ohm, corresponding to 837W. Does all this
                    suggest summat?

                    Is it a scientific breakthrough, and do you have in your possession a heater
                    element operates at between 6.9 and 11% above its declared rating (both
                    wattage and current), and that decreases in resistance as it heats up ...
                    MIT will be beating a path to your door! Or, as I suspect, do you have a
                    case similar to Fred the Wheel Tapper's hammer? You probably know the story
                    ... Fred the Wheel Tapper's job was to detect cracks in train wheels by
                    tapping them with his hammer. A dull, hollow sound instead of a mellow
                    boing indicated a crack in the wheel. One week he rejected over 2000 wheels
                    ... until they discovered he had a crack in his hammer.

                    You also have an odd procedure. You say you use the small 750W element for
                    stripping, but use 1100W max for rectification.. Do you have two elements
                    perhaps, and if you do then why strip at low power? Mebbe I've got it all
                    wrong and you have one 1100W element that you throttle down for stripping
                    (your choice). But then the resistance of the element is just 12 ohms and
                    all bets on your measurements are off.

                    Got me bewildered, I must admit :-))

                    All the best,
                    Mike N
                  • Mark
                    big snip. The stripping still has a 3kw@240VAC that I run at 110VAC. That power level works out just fine. Plug it in at 5AM with 16GAL of 15% ish ferment at
                    Message 9 of 12 , Feb 9, 2005
                      big snip.

                      The stripping still has a 3kw@240VAC that I run at 110VAC. That
                      power level works out just fine. Plug it in at 5AM with 16GAL of 15%
                      ish ferment at 16C or so, by noon I'm drawing product at a
                      relatively fast rate, by 9PM I pull the plug after collecting about
                      3GAL of liquid.

                      The 2ndary still sits on a 1100W hot plate. Max power to heat up,
                      then I turn down to about 70% or so.

                      I signed out a true RMS watt meter from work for this weekend. I'll
                      try it on both stills.

                      Mark
                    • suitcase1499@aol.com
                      In a message dated 2/9/2005 7:36:51 PM Eastern Standard Time, markgofast@hotmail.com writes: I signed out a true RMS watt meter from work for this weekend.
                      Message 10 of 12 , Feb 9, 2005
                        In a message dated 2/9/2005 7:36:51 PM Eastern Standard Time,
                        markgofast@... writes:

                        I signed out a true RMS watt meter from work for this weekend. I'll
                        try it on both stills.

                        Mark



                        Well totally against popular belief the Lutron 1500 watt light dimmer is
                        working fine for me it's not really getting very hot but I'm still going to
                        install a small fan on it.

                        Suitcase


                        [Non-text portions of this message have been removed]
                      • Levi Langershank
                        ...so you strip with 750W and do your final run with 770W....: ) Levi (THIS REPLY HAS BEEN OFFICIALLY EDITED) ...
                        Message 11 of 12 , Feb 9, 2005
                          ...so you 'strip' with 750W and do your final run with 770W....:>)

                          Levi

                          (THIS REPLY HAS BEEN OFFICIALLY EDITED)

                          >From: "Mark" <markgofast@...>
                          >Subject: [Distillers] Re: Heating Element Controller
                          >The stripping still has a 3kw@240VAC that I run at 110VAC.


                          >The 2ndary still sits on a 1100W hot plate. Max power to heat up,
                          >then I turn down to about 70% or so.
                          >
                          >I signed out a true RMS watt meter from work for this weekend. I'll
                          >try it on both stills.
                          >
                          >Mark

                          _________________________________________________________________
                          Is your PC infected? Get a FREE online computer virus scan from McAfee´┐Ż
                          Security. http://clinic.mcafee.com/clinic/ibuy/campaign.asp?cid=3963
                        • Mark
                          ... different stills, and different time management techniques. It s probably not the best or most efficient method, but it works for me. I transfer the
                          Message 12 of 12 , Feb 9, 2005
                            > ...so you 'strip' with 750W and do your final run with 770W....:>)
                            >

                            different stills, and different time management techniques. It's
                            probably not the best or most efficient method, but it works for me.

                            I transfer the ferment and plug in the stripper still at 5 or 6 or
                            7AM on Saturday when I wake up, and unplug it late Saturday sometime
                            after dinner. I have enough failure mode detectors on it to shut it
                            down if something messes up. (yea, I did a PFMEA on it. I'm that
                            anal).

                            Kinda the same for the 2ndary still. 3 gal from strip + 1.5 gal
                            reruns, collected into 9 bottles at a rate of 2 hrs per bottle. I
                            spend 3 minutes every 2 hrs swapping bottles.
                          Your message has been successfully submitted and would be delivered to recipients shortly.