question about electric range burner controls

Discussion in 'Misc DIY' started by nick, Jan 30, 2009.

  1. nick

    nick Guest

    The last three electric ranges I have owned (all with the usual
    "infinitely variable" surface unit control) have occasionally just
    shut off on the lowest setting. Normally this setting will maintain a
    simmer, but when the control decides to screw up, it will let the
    temperature of the pot drop to 180 degrees or even lower. I have just
    assumed that there is no solution to this problem, but it is very
    annoying, and maybe somebody out there has an answer. The old style
    burner/control with two or more coils hooked in series or parallel at
    110 or 220 was a lot more predictable. I guess I don't understand why
    we can't devise a better control.
     
    nick, Jan 30, 2009
    #1
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  2. nick

    dpb Guest

    nick wrote:
    ....
    > ... I guess I don't understand why
    > we can't devise a better control.


    Cost.

    --
     
    dpb, Jan 30, 2009
    #2
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  3. nick

    Tony Hwang Guest

    dpb wrote:
    > nick wrote:
    > ...
    >> ... I guess I don't understand why
    >> we can't devise a better control.

    >
    > Cost.
    >
    > --
    >

    Hmmm,
    Analog vs. digital control.
     
    Tony Hwang, Jan 30, 2009
    #3
  4. nick

    J. Clarke Guest

    dpb wrote:
    > nick wrote:
    > ...
    >> ... I guess I don't understand why
    >> we can't devise a better control.

    >
    > Cost.


    How does the control sense the temperature in the pot? Most of them
    are simply variable resistors or if someone is going for efficiency
    triacs that vary the power input. They do no temperature sensing at
    all unless there's an overtemp protective circuit.

    To be usefully better the control would have to sense the temperature
    in the pot. There have been attempts to do this but they generally
    involve dangling a probe into the food.

    --
    --
    --John
    to email, dial "usenet" and validate
    (was jclarke at eye bee em dot net)
     
    J. Clarke, Jan 30, 2009
    #4
  5. nick

    Smitty Two Guest

    In article
    <>,
    nick <> wrote:

    > The last three electric ranges I have owned (all with the usual
    > "infinitely variable" surface unit control) have occasionally just
    > shut off on the lowest setting. Normally this setting will maintain a
    > simmer, but when the control decides to screw up, it will let the
    > temperature of the pot drop to 180 degrees or even lower. I have just
    > assumed that there is no solution to this problem, but it is very
    > annoying, and maybe somebody out there has an answer. The old style
    > burner/control with two or more coils hooked in series or parallel at
    > 110 or 220 was a lot more predictable. I guess I don't understand why
    > we can't devise a better control.


    We did. It's called a gas valve. But since you're limited to or addicted
    to electric, maybe you could put a current sensor in the circuit to let
    you know if the burner goes off.

    We also devised a better way to get to usenet. Or more accurately,
    Google devised a worse way to get to usenet. Look into it some time.
    Many people here, including me, filter googlegroups and won't see posts
    from there unless someone else responds to them.
     
    Smitty Two, Jan 30, 2009
    #5
  6. nick

    nick Guest

    On Jan 30, 12:22 pm, "J. Clarke" <> wrote:
    > dpb wrote:
    > > nick wrote:
    > > ...
    > >> ... I guess I don't understand why
    > >> we can't devise a better control.

    >
    > > Cost.

    >
    > How does the control sense the temperature in the pot?  Most of them
    > are simply variable resistors or if someone is going for efficiency
    > triacs that vary the power input.  They do no temperature sensing at
    > all unless there's an overtemp protective circuit.
    >
    > To be usefully better the control would have to sense the temperature
    > in the pot.  There have been attempts to do this but they generally
    > involve dangling a probe into the food.
    >
    > --
    > --
    > --John
    > to email, dial "usenet" and validate
    > (was jclarke at eye bee em dot net)


    These controls don't sense the temperature in the pot, they just
    switch current on and off controlled by some kind of bimetal device
    inside the control. Ideally, on-time to off-time ratio should be
    constant for any given control setting, with the ratio varying from 1
    (max heat) to some fairly small fraction when you set the control on
    its lowest setting, and what happens on the lowest setting is that
    this ratio is totally undependable. Most of the time it is correct,
    like maybe 1:20, but occasionally the same control setting produces a
    ratio like 1:40. At the higher settings it is dependable. Clearly a
    digital control which just measured a time interval directly would be
    better. Maybe when the stoves come from China....

    And incidentally, gas stoves have their own idiosyncrasies. They
    waste a lot of heat lost to the room, they smell, they steam up the
    windows in winter, and they are often slower to boil water than an
    electric stove. They do mostly hold a setting, but that setting can
    be difficult to achieve. The problem I am complaining about is not
    caused by the energy source, it is just bad engineering.
     
    nick, Jan 30, 2009
    #6
  7. nick

    Guest


    >

    x-no-archive:

    >  Most of them
    > are simply variable resistors...........
    >


    why do people that are GUESSING at the answer feel the need to post
    their GUESSES and give out wrong information...

    Mark
     
    , Jan 30, 2009
    #7
  8. nick

    J. Clarke Guest

    wrote:
    > x-no-archive:
    >
    >> Most of them
    >> are simply variable resistors...........
    >>

    >
    > why do people that are GUESSING at the answer feel the need to post
    > their GUESSES and give out wrong information...


    OK, so how do they work, o expert?

    --
    --
    --John
    to email, dial "usenet" and validate
    (was jclarke at eye bee em dot net)
     
    J. Clarke, Jan 30, 2009
    #8
  9. nick

    Guest

    On Jan 30, 5:53 pm, "J. Clarke" <> wrote:
    > wrote:
    > > x-no-archive:

    >
    > >> Most of them
    > >> are simply variable resistors...........

    >
    > > why do people that are GUESSING at the answer feel the need to post
    > > their GUESSES and give out wrong information...

    >
    > OK, so how do they work, o expert?
    >
    > --
    > --
    > --John
    > to email, dial "usenet" and validate
    > (was jclarke at eye bee em dot net)


    Nick explained it correctly..

    If they used a "variable resistor" the control would get as hot as the
    element.

    Mark
     
    , Jan 31, 2009
    #9
  10. There was another control that didn't cycle off and on like the infinite
    controls. It was the old seven button push button switch that GE used to
    use. The burner itself was two separate coils with four terminals. I
    don't remember if the individual coils were the same size, or if one was
    larger than the other. As I recall (it's only been about 35 years since
    their operation was explained to me) the switch had a neutral going to
    it as well as the two hot leads. On the highest setting it put a
    constant 240 to both segments of the burner. On the lowest, the switch
    put both segments in series and put 120 to it. The settings between
    highest and lowest did various combinations of voltage and
    series/parallel on the two segments of the burner. I forget the exact
    sequence from low to high-- I always wondered how long it took someone
    to design the switch to do all the different configurations. They must
    have been pretty reliable. I don't remember ever changing one when we
    used to work on stoves, and I still see some in operation. Larry
     
    Lp1331 1p1331, Jan 31, 2009
    #10
  11. nick

    Tony Hwang Guest

    wrote:
    > On Fri, 30 Jan 2009 18:17:03 -0800 (PST), wrote:
    >
    >> Nick explained it correctly..
    >>
    >> If they used a "variable resistor" the control would get as hot as the

    >
    >
    > Nick is right.
    > There is a bi-metal strip (bends when you heat it) with a contact
    > point on the end and a coil of wire that is energized when the contact
    > makes. As it heats up, along with the burner, the contact opens. When
    > the bi-metal strip cools the contact makes again. They move the other
    > contact in and out when you turn the knob to regulate when it breaks.
    > As they age the strip takes a set and is not linear anymore.
    >
    > http://gfretwell.com/electrical/stove control.jpg
    >
    > From a Whirlpool cooktop

    Hi,
    New ones don't have bi-nmetal strip/contacts. It is like a light dimmer
    using S.S. device.
     
    Tony Hwang, Jan 31, 2009
    #11
  12. On Fri 30 Jan 2009 10:22:51a, J. Clarke told us...

    > dpb wrote:
    >> nick wrote:
    >> ...
    >>> ... I guess I don't understand why we can't devise a better control.

    >>
    >> Cost.

    >
    > How does the control sense the temperature in the pot? Most of them
    > are simply variable resistors or if someone is going for efficiency
    > triacs that vary the power input. They do no temperature sensing at
    > all unless there's an overtemp protective circuit.
    >
    > To be usefully better the control would have to sense the temperature
    > in the pot. There have been attempts to do this but they generally
    > involve dangling a probe into the food.
    >


    Years ago Sears used to sell a Kenmore electric range with coil burners.
    Some were equipped with a spring-loaded button in the center of the coils
    that made contact with the pot and sensed the temperature. The control
    dial was calibrated in degrees. It worked rather well. I believe that
    some radiant glass top units may have similar function. They can sense if
    there is a pot on the burner and will turn off if there isn't.

    --
    Wayne Boatwright
    e-mail to wayneboatwright at gmail dot com
    ************************************************************************
    Date: Saturday, 01(I)/31(XXXI)/09(MMIX)
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    Countdown till President's Day
    2wks 1dys 5hrs 30mins
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    Cats must try to climb on the human's lap when he/she is using the
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    Wayne Boatwright, Feb 1, 2009
    #12
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