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Microwave Question

Discussion in 'Electronic Repair' started by JBreits, Jun 27, 2005.

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  1. JBreits

    JBreits Guest

    When heating up small amounts of cooked vegetables (i.e. 10-20 peas or
    10-20 kernels of corn, small pieces of carrots, broccoli), I almost
    always notice "sparking" in the food after about 5 sec. And if I
    continue heating, it will actually produce flames usually in 10-13
    seconds.

    I have an 1100watt Emerson microwave. It seems to do about the same
    thing on all 10 power levels (although it may happen quicker on higher
    power levels). I have only noticed it with vegetables.

    Is this occurring just because there is such a small amount of food
    being heated? Is it just getting so hot that it causes fire? When I
    take it out, it doesn't feel that hot. Could the microwave have
    something wrong with it?

    Thanks,
    JBreits
     
  2. NSM

    NSM Guest

    You have powdered metal in your food? Tried adding water?

    Add a separate cup of water - not to the food.

    N
     
  3. Cobalt

    Cobalt Guest

    ya, could be hard water...have seen old iron pipes that run underground make
    the water hard because the rust gets into the water.

    |
    | |
    | > When heating up small amounts of cooked vegetables (i.e. 10-20 peas or
    | > 10-20 kernels of corn, small pieces of carrots, broccoli), I almost
    | > always notice "sparking" in the food after about 5 sec. And if I
    | > continue heating, it will actually produce flames usually in 10-13
    | > seconds.
    |
    | You have powdered metal in your food? Tried adding water?
    |
    | Add a separate cup of water - not to the food.
    |
    | N
    |
    |
     
  4. NSM

    NSM Guest

    And slamming 1100 W into 10 kernels of dry corn isn't going to work either!

    N
     
  5. darren

    darren Guest

    my first thought is that is normal, I take it all is fine with a
    regular amount of <food> ?

    on side note, why you nuking 20 kernals of corn ?
     
  6. Arfa Daily

    Arfa Daily Guest

    When you say it does it on all 10 power levels, you are not seeing the
    operation from the right viewpoint. You cannot control the output power of a
    magnetron. It's either producing microwaves at full chat, or not at all. The
    power setting is controlled by interupting the amount of time that the mag
    is turned on for, so at 100% power, it's running all the time, at 50% power,
    it's only running for half the time and so on. You will probably have heard
    the transformer going KAWOMM as the mag cuts in and out.

    This means that you are hitting those poor peas with 1100 watts of RF each
    time the mag cuts in. Even if you are down on 10% power and you set the
    timer for 1 minute, the 6 seconds that the mag would be on during that time
    ( probably three bursts of 2 seconds ), will probably be enough to make the
    poor peas explode ...

    The cup of water is a sound idea, as it provides a better load for the
    magnetron. Very small quantities of food represent very little load, and
    this can lead to rapid demise of the mag.

    Geoff
     
  7. Nomen Nescio

    Nomen Nescio Guest

    This isn't quite true for all microwave ovens. Panasonic and several other
    brands use "inverter technology"

    "True Microwave Power Levels
    Conventional microwave ovens operate on only one power level; the microwave
    energy is either on or off. For example, when set at 60% power, a
    conventional microwave cooks at full power 60% of the time, and remains
    idle the rest of the time. This on/off delivery of cooking power can result
    in cold spots and overcooked edges. Panasonic Inverter technology delivers
    true low, medium and high power levels. This targeted "soft" penetration of
    microwave energy into the center of your food helps prevent overcooking on
    the edges and surfaces, and provides more even cooking compared to
    conventional microwaves."

    I have heard though that the inverter technology is more prone to failure
    in the power supply.
     
  8. JBreits

    JBreits Guest

    Thank you for all the replies. I should clarify a little I guess. I
    have a one-year old that eats cooked veggies (only the small ones). I
    usually cook up enough to last a week and we put them in the fridge.
    When it comes time for her to eat we put a little in the microwave just
    to warm them up. This could be ~20 Kernels of corn and ~20 peas and a
    couple pieces of carrots. We don't usually heat up a whole bunch in
    case she is feeling like being a picky eater that day.

    In response to other messages, we do have slightly hard water, but I
    see no sparking or anything when heating the tap water. The vegetables
    are boiled in a non-stick pan. Could that be a problem? Other things
    that I have cooked in the pan microwave fine.

    Last night I tried putting a small bowl of water in with the food and
    there was no sparking or fire or anything. So perhaps it really is
    just the fact that there was a small amount of food.

    Does that sound reasonable?

    Thanks,
    JBreits
     
  9. Absolutely.

    It has nothing to do with hard water.

    Probably, simply the fact that you have a very small amount of material
    that absorbs the microwaves creating a very high field strength in that
    area and that its dimensions are similar to a fraction of a wavelength
    at 2.45 GHz.

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    Important: Anything sent to the email address in the message header above is
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    contact me via the Feedback Form in the FAQs.
     
  10. Ken Weitzel

    Ken Weitzel Guest

    <snip>

    Hi...

    May I offer a non-technical suggestion? :)

    (I raised one of the world's most picky eaters)

    How about doing up a reasonable helping of veggies - perhaps
    a half cup or so - and then having some with her?
    I found it helpful to join mine, each with our own plate,
    and as each of us had a "bite" I'd comment on mine.
    (smile, say "good", "ummm", "hurray" and so on.) Didn't take
    long before we were sort of taking turns, and each praising
    it)

    And just another thought; with no disrespect intended.
    She may enjoy it more if she had them not previously
    cooked but rather micro'd from frozen. I'm old now,
    but still use the frozen in a bag ones. A half cup
    in a cereal bowl, add a tablespoon or two of water, then
    zap on high for 90 seconds is just right. (Of course
    I'd feel them first before offering them to a baby)

    Take care.

    Ken
     
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