Microwave Oven Should Stop Operation if The Door Open Button Is Pressed: Is This a Standard Feature?

• 

  retiredfeline on 26/03/2016 - 00:31

  +4

  All the ovens I've seen have this safety feature. And besides the effectiveness of the heating is affected if the cavity is not closed.

  • 

    bluesky on 26/03/2016 - 00:33

    Even cheaper ones, I take it.

• 

  [Deactivated] on 26/03/2016 - 00:38

  +1

  It should be a standard safety feature an i assume its an australian standard for these type of devices.
  Mine has 2 safety kill switches 1 in the door so if you open the door without using the button and also the button itself has a contact to cut power when the open button is pressed.

  • 

    scrimshaw on 26/03/2016 - 01:27

    +2

    There's someting inside the oven called the interlock switch. It's written down in a lot of microwave service handbooks.

    http://www.microtechfactoryservice.com/switch.html

    If the mechanical safeties fail, the oven is designed to short the main power supply and blow the internal fuse.

• 

  bluesky on 26/03/2016 - 00:48

  Thank you guys, that is reassuring.

  • 

    scrimshaw on 26/03/2016 - 01:11

    +2

    To reassure you even further, microwave energy is not the same as nuclear radiation — it won't give you cancer or two-headed progeny. It's basically harmless and is actually often used in telecommunications.

    It's just that the microwave energy from a microwave oven is at just the right frequency to cause water molecules to vibrate, in the same way a crystal wine glass will vibrate (and eventually shatter) when exposed to a sound wave tuned to its resonance frequency. It's the vibration of these water molecules that heats the food up. Unfortunately, you and I are mostly composed of water so exposure to a microwave energy emitter will cause some pretty serious hurt.

    But similar as to how you wouldn't put your face or hand over a cooking stove, you'd probably never want to stick close to a leaking microwave anyway, because it burns like a b!@tch.

    • 

      bluesky on 26/03/2016 - 01:31

      Firstly, thanks for the explanation.

      Vaguely remember reading something in the past about end-of-life or defective microwave ovens which may leak some microwave energy. Not sure if there is any substance to this.

      But let's say it is possible to be exposed to low-level "escaped" microwave energy, can one know or feel it? Will it be painful? Do you know?

      Or is it like radio frequencies from cell tower, mobile phones etc, where there is also speculation that they may have adverse effects on health. But with those, you can't feel it.

      Of course, it is better if one can feel it, then one can avoid it.

      • 

        psyren89 on 26/03/2016 - 03:22

        +1

        You probably would feel it if it were concentrated on one spot and powerful enough. Leakage from a microwave is highly unlikely to be harmful.

• 

  nikkirose on 26/03/2016 - 04:00

  +1

  I have fixed many a dead microwave with a $3.50 NEC fuse.

  • 

    bluesky on 26/03/2016 - 04:41

    Would like to get some thoughts from you and others who have fixed microwave ovens before, whether this seems like something that is easily fixed.

    My microwave oven often stopped at 20 seconds, irrespective of whatever timing I set.
    But food was still being cooked/warmed during the 20 seconds. I just had to add more time and start it again.

    Then, a couple days ago, the food no longer got warm or cooked, indicating that there is no longer microwave energy hitting the food. But it still turned for 20 secs.

    Does this sound like an easy problem to fix, like maybe replacing the fuse or something?

    Thanks in advance for any advice.

    • 

      nikkirose on 26/03/2016 - 06:04

      +1

      I am not that technical, but for 3 bucks, I always give it a try, if it doesn't work I have a fuse laying around for the next one. I just take the fuse out, take it to an electronics shop and say can i have a new one of these.

      • 

        SchnishSchnack on 26/03/2016 - 07:11

        +4

        3 bucks for fuse wasted given symptoms described. Other things involved- electronic controls at very least.

    • 

      altomic on 26/03/2016 - 09:12

      +1

      I've had this problem. It could mean that the magnetron tube (which emits microwaves to heat your food and looks like a huge capacitor the size of a 200ml can of softdrink) is either stuffed or "buggy". The tube may still hold charge and can be lethal if not discharged. I " fixed" my current microwave (30ltr stainless steel panasonic near new from eBay 99cents) by first grounding the plug (I literally plug the microwave into the ground) and letting the microwave sit unplugged for a week, then taking the cover off then DANGEROUS PART using a screw driver taped to a piece of electricians nonconductive tubing I short the magnetron. It should be discharged already and there shouldn't be a spark but always always be cautious. The magnetron can hold charge just like a capacitor. Twice doing this has brought working-but-non-heating microwaves back to life. Maybe I'm off track and it was a fluke that the microwaves started working again but that's what I did and then they were heating again.

      About the author: I studied electronics/circuitry for 12 months at TAFE so I could learn how to reduce the risk of electrocuting myself.

      • 

        bluesky on 26/03/2016 - 16:52

        Thanks for sharing your experience.

• 

  SchnishSchnack on 26/03/2016 - 07:09

  +1

  Some various things for you:

  From American FDA website, but also applicable here.

  A Federal standard limits the amount of microwaves that can leak from an oven throughout its lifetime to 5 milliwatts (mW) of microwave radiation per square centimeter at approximately 2 inches from the oven surface. This limit is far below the level known to harm people. Microwave energy also decreases dramatically as you move away from the source of radiation. A measurement made 20 inches from an oven would be approximately one one-hundredth of the value measured at 2 inches.
  The standard also requires all ovens to have two independent interlock systems that stop the production of microwaves the moment the latch is released or the door opened. In addition, a monitoring system stops oven operation in case one or both of the interlock systems fail. The noise that many ovens continue to make after the door is open is usually the fan. The noise does not mean that microwaves are being produced. There is no residual radiation remaining after microwave production has stopped. In this regard a microwave oven is much like an electric light that stops glowing when it is turned off.
  Although FDA believes the standard assures that microwave ovens do not present any radiation hazard, the Agency continues to reassess its adequacy as new information becomes available.

  Microwave Ovens and Health
  Much research is under way on microwaves and how they might affect the human body. It is known that microwave radiation can heat body tissue the same way it heats food. Exposure to high levels of microwaves can cause a painful burn. The lens of the eye is particularly sensitive to intense heat, and exposure to high levels of microwaves can cause cataracts. Likewise, the testes are very sensitive to changes in temperature. Accidental exposure to high levels of microwave energy can alter or kill sperm, producing temporary sterility. But these types of injuries - burns, cataracts, temporary sterility - can only be caused by exposure to large amounts of microwave radiation, much more than the 5mW limit for microwave oven leakage.
  Less is known about what happens to people exposed to low levels of microwaves. Controlled, long-term studies involving large numbers of people have not been conducted to assess the impact of low level microwave energy on humans. Much research has been done with experimental animals, but it is difficult to translate the effects of microwaves on animals to possible effects on humans. For one thing, there are differences in the way animals and humans absorb microwaves. For another, experimental conditions can't exactly simulate the conditions under which people use microwave ovens. However, these studies do help us better understand the possible effects of radiation.
  The fact that many scientific questions about exposure to low-levels of microwaves are not yet answered require FDA tocontinue to enforcement of radiation protection requirements. Consumers should take certain common sense precautions.

  This is the full page http://www.fda.gov/Radiation-EmittingProducts/ResourcesforYo…

  I would suggest that you also read many of these links Some more reading for you and info there will also clearly answer remaining questions you have, I would think. Read closely the warning in that first link. I've fixed various things, but I'm not a microwave oven repairman. Buying a new even if cheap oven may be your best course if you are otherwise planning to try risky things with old and now maybe fundamentally faulty one… No resurrection for you this Easter if you do something really silly!

  • 

    bluesky on 26/03/2016 - 16:57

    +1

    Great reading material, and provide answers to questions I have - thanks very much.
    LOL - the no resurrection part :-) Yes, will be careful … and most likely will just get a new one.

    Still, it is all quite interesting …

• 

  windale on 26/03/2016 - 12:25

  +1

  reminds me of this interesting discovery from the Dish in Parkes NSW:

  https://theconversation.com/how-we-found-the-source-of-the-m…

  • 

    bluesky on 26/03/2016 - 17:05

    yeah :-)