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Psst, hey Engineers.... (or microwave specialists...) question...


Coytee

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Needed a new stove.  Bought a Kitchenaid slide in with induction top.  Only choice is/was stainless.

 

My existing (also Kitchenaid) stove and microwave were white.

 

Wanting things to match, I arbitrarily decided to also buy a new microwave.

 

Total spent, about $4K

 

Not once, but twice, we had a plate explode inside the microwave.  Plates are maybe 20+ years old and have been used any number of times inside our old microwave.  Plates are stamped "microwave safe" on the underside.

 

Mind you, this happened inside of 3-4 weeks of ownership.

 

Got service out and he checked the wall power (fine) and checked something on the unit itself (plugged a box into the outlet and plugged the microwave into the box, I think it measured how many volts it was using?)

 

Anyway it checked out fine and he said it was an old plate.

 

I said I wasn't buying that...  now if he said "I don't know", I can accept that...

 

Called Kitchenaid again and said "what are we going to do about this", she said how about a second opinion?

 

So, second unrelated service guy comes out, does same procedures.....same opinion in the end.

 

"this unit is rated at 1200 watts and your plates are old....they probably had some air pockets inside them and that caused the plate to crack"

 

Ok, suppose I buy that...  what burnt the center of the bacon like a photon beam on high?

 

 

 

So that is essentially where it's left...  he walked out as the first guy saying "it's functioning properly"  

 

I'm scratching my head.

 

Any thoughts as to what might be causing this?

 

Microwaves are supposed to be an item to make life simple....warm your coffee?  60 seconds...  want to make bacon...6 minutes...  not 6 minutes and BLAM!

 

Any thoughts as to what's burning a hole in the center.

 

I might add, the plate was rotating and the burn was about the size/shape of a silver dollar.  Wife simply hit "add a minute" which defaults the unit to high power for "X" minutes.

 

I would have thought the microwaves would be bouncing around in there, somewhat evenly, not focused on a single spot.

 

 

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I have a kitchenaid microwave and it is great.  It doesn't spread the microwave energy quite as good as it should, more to the center but not as bad as yours.  Seems like something is out of adjustment.

 

Here's an interesting patent.  I wonder if there is something similar in yours that is defective - https://www.google.com/patents/US20140197163

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Richard,

 

Think about subwoofer room acoustics, and how uneven they are.  In the case of microwaves, their wavelengths are 4.75 inches (12 centimeters) long, which is still "nearfield", so you will get a focusing effect in the middle of the oven. 

 

Some points to consider:

  1. Always place your food to one side on the platter--never in the center of the platter. Newer microwave ovens have new magnetrons, which perform better than old magnetrons in older microwave ovens.  That includes accentuating the center-oven hot spots.
     
  2. Old ceramic plates eventually form micro-cracks somewhere on their surface due to things like knives cutting on their surfaces or knocks/scrapes somewhere on their edges, etc. That usually lets in water/moisture. 
     
  3. If the plate is made out of CorningWare or Corelle, its surface is actually in compression, until at least someone scratches it and then places it in a microwave oven.  At the point where its surface is no longer in compression, it usually explodes...like yours did.  I avoid CorningWare for that reason, because of users' tendency to use it in places where it will eventually explode due to thermal stresses opening up its surface compression.

    Recommend using plain glass or just paper towels to soak up the juices/overflow.  The cheapest kind of glass plates usually work best (like the one that forms the rotating turntable in the oven)--or plastic plates that aren't hydroscopic or have polar molecules, i.e., they don't soak up microwave energy and get hot inside a heating microwave oven.

Chris

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That is a sad state of affairs.  One being, the cooking of bacon in a microwave. :(Thats not the way to do it.  The best way to do bacon is in a 400 degree oven, for about 14 minutes or so, or until its reached its perfect doneness,  no spatter, little smell, until done that is.  One thing you can do is to set the micro to run at less than full power. it seems your new one is putting a lot more energy than your old one.  

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D*mn that's just not right.

Our experience the past twenty years with kitchen aid has led to them and whirlpool being banished from the premises @Coytee. It's not 1975 anymore. The  KEBC171 suicide oven that was $800 about twelve years ago, self-clean function melts the motherboard components . Replaced once then class-action success. Whirlpool gas stove eight years ago... the grate you put the pots on. You won't believe this. It bowed and bent and sank...the darn cooking grate couldn't handle the heat. Made to go over flames it failed under hot temperature. Replaced once and we still deal with it. The labeling for the dails came off with 409 and a paper towel until now...low med high were completely gone after four years. They said clean it with soft cloth and mild detergent. Really?... do they cook more than h20 on their stoves? It's good we're used to it, but have to tell other family how to do it!

Their attitude toward me was that I was using it wrong therefore they would not help up and became mean-spirited with our persistence for a remedy under warranty.

Lifelong customer lost.

Panasonic Cyclonic Inverter waves do good. Their open / close buttons are cheap though. The percentage of cooking power you set it for is how it cooks for the entire time you set, no bursts to equate to 80% power for four min it literally cooks at 80% of the 1250w for the entire time. When I'm too lazy to do nachos in the oven (sacrilege, I know) this wave melts the cheddar evenly over a 13" plate no puddles, no not melted spots.  It can melt a stick of butter without scorching it. I love my microwave!

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Interesting comments, thank you all.

 

Never having paid attention, the service guy explained to me the two different sounds from the machine....one with the magnetron working and one with it idle.

 

When you put something in and hit "add minute" "X" number of times for minutes, it defaults the unit to highest power for that time frame.

 

Instead, if you go to another button, put in "X" minutes at say, 80%, then the magnetron will turn on 80% of the time and turn off the other 20%, allowing the little waves inside to bounce around I guess.

 

I will say, when the microwave was plugged into his unit (which was then plugged into the wall) when we hit full power, it pulled full watts...when we went to 50%, it dropped to 50% so I can see where he says it's dead on.

 

Thing is....this darn thing comes with not one, not two, not three but FOUR full pages of laminated instructions on how to cook everything from a piece of bacon to a souffle.  Wife got a look at that and instead of thinking wow, how versatile, thought instead, how annoying....  life just got more complicated.

 

Regarding the bacon in there, that is actually her 'faux' bacon (she's vegan) I usually make mine (real) on the stove or sometimes, in the oven.

 

The only two times it's blown a plate where when she happened to be making her faux bacon, never with me. Now she's a bit spooked.

 

 

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21 minutes ago, Coytee said:

The only two times it's blown a plate where when she happened to be making her faux bacon, never with me. Now she's a bit spooked.

Just mention to her to put a small glass of water in with the fake bacon to slow down the heating process, and thereby reducing the probability of exploding another plate. 

 

I think that the moisture and fat content of fake meat products vary and it tends to escape rapidly and completely, at which point the ensuing microwaves will fry your plate in addition to the fake meat.  A small glass or little bowl of water will ensure that doesn't happen.  It's also much easier on the magnetron life.

 

Chris

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Without knowing too much . . . some microwave ovens have "stirrers" which are fan-shaped devices which spread the waves around the oven cavity.  It could be that yours is not working and the energy gets concentrated in the center.

I see charring in the photograph.  It could be that the intense heat of the food is causing thermal stresses in the ceramic plate and cracking it.  It is not that the plate is absorbing the energy. 

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18 hours ago, WMcD said:

Without knowing too much . . . some microwave ovens have "stirrers" which are fan-shaped devices which spread the waves around the oven cavity.  It could be that yours is not working and the energy gets concentrated in the center.

I see charring in the photograph.  It could be that the intense heat of the food is causing thermal stresses in the ceramic plate and cracking it.  It is not that the plate is absorbing the energy. 

Something of this nature has to be happening.  No reason for the bacon to be charred in the middle but not fully cooked on the ends.  That would imply the beam is like a laser.  Not good.  My Kitchenaid does get hotter in the middle but only by a tiny bit.  Something is amiss. 

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No solution to the cracking plates but I cook the bacon (3 strips) sandwiched between two plates, one inverted/covering over the other for 3 minutes and it comes out perfect.

No greasy fat and all crisp.

JJK

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Search for that Panasonic Cyclonic Inverter folks. It's a change in the way the waves are put into the cavity. It swirls them around on the inside and heats more evenly. Swear it is the best thing since I saw that  Amana Radar Range at grandma & grandpas house in c.1975.

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@Coytee how long did you cook the bacon?  I've seen on-line the max cook time is 3 minutes.

http://www.dailymail.co.uk/femail/food/article-3220700/Can-REALLY-cook-perfect-crispy-bacon-three-minutes-microwave.html

 

I'm guessing your bacon produced grease and then the microwave oven caught the grease on fire, which caused the explosion/burn.

 

If you don't have problems with any other food in the microwave I would simply not cook the fake bacon that way anymore.

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Wife has gone vegan so she won't eat the real stuff....that's for me.  (nice side effect I might suppose?)

 

As far as grease fire...nope....  she was there for the first event (plate actually 'blew up' while in her hand) and I was there for the second.  In fact, was keeping an eye on things through the little window (actually reasonably large window in this case)

 

No fires.  Just a scalding of the center then....BOOM

 

Duration?  I don't recall but I want to say it was around 2 1/2 to maybe 3 minutes.  It isn't like it was in there for 45 minutes.

 

I spoke with their 'safety department' (or something like that) just yesterday.  Found out I can email the picture to them.  I think that will show them a lot more clearly what I'm talking about than me just trying to describe it over the phone (and them thinking someone is just getting hysterical, blowing it out of proportion)

 

Not heard anything back yet but fingers are crossed for some kind of commentary from them.

 

To repeat, the wife has been making her bacon like this for probably 9-10 years (don't recall exactly when she turned vegan) and simply followed the same process she's used every time.  This is the new result.

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1 hour ago, Coytee said:

Wife has gone vegan so she won't eat the real stuff

There's the problem.  :lol:

 

Maybe this new microwave is more powerful than the old one.  I don't know the problem, but maybe the solution is to reduce the power to see if that cooks the bacon but doesn't blow it up?

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My wife does not like out present microwave because the electronic number pad went bad and I fixed it with a toggle switch. So i picked up a microwave at a yard sale, brought it home and it blew up two plates back to back. In to the trash it went and out came the old one.

Sent from my EM756 using Tapatalk

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Typical microwave ovens use a normal transformer to step up the voltage for the magnetron. These are the ones that use longer duty cycles to adjust power. You can hear them turn on and off when say in 80,% 0r 50% power mode.   Panasonic "inverter" use a switch mode pulse width modulated power supply that pulses power much faster thereby adjusting power more smoothly.   Microwave ovens also have "mode stirrers" that effectively disturb standing waves.  

 

So what is happening in yours?  hmm I agree that corning ware will break after a couple decades so that is not unusual. But why all of a sudden?  Perhaps your new microwave is much more powerful than the older one?  Maybe its mode stirrer is not as effective as the old one?  

 

btw microwave oven transformers make great electric arc science projects!  even better than flyback transformers!  

 

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  • Moderators
On 7/7/2017 at 9:27 PM, wvu80 said:
On 7/7/2017 at 7:59 PM, Coytee said:

Wife has gone vegan so she won't eat the real stuff

There's the problem.  :lol:

True, just tell the wife everyone knows microwaves are not vegan approved, the microwaves bouncing off of previous meat products is contaminated with meat residue which reacts with "near bacon" in a negative way. It's just science, can't change it, is she fell for the vegan thing she might buy it ?

 

Only You Coytee  

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  • 1 month later...

The rest of the story...(I don't think I mentioned it above....if so, you get to enjoy reading about it again!)

 

So, I call Whirlpool...ask what the update is?

 

"Case has been closed"

 

 

WHAT?

 

"The technician said you were using non-microwave plates and admitted you didn't know how to operate the microwave"

 

Hmmm...  (I actually cut her off here)

 

"Do you see those pictures I sent to your help desk?  They're posted to my service number"

 

"yes"

 

"Take a look at them....  I presume you have a microwave of some sort....  I presume you have made bacon in your microwave...  I presume you know what a microwave safe plate is and how to read...  now...  if this was YOUR bacon.....would you THEN feel that this unit is working properly???"

 

"Sir....can you please hold for a minute?"

 

 

(tick tock, tick tock, tick tock....)

 

"ok, sir...  I've spoken to my manager and I have been authorized to issue you a buyback check.  If you can get me a copy of your receipt, we'll cut you a check for what you paid, send the check to our service technician and have him come pick it up....  is that ok?"

 

It's currently 8:20 and the service tech just left.  I'm holding a check in hand for $950

 

He said he normally gets orders to destroy buy-back units however....  they want him to physically box this unit up and send it back to them so the engineers can look at it.

 

 

I find it interesting that in one breath, they were saying case closed since I'm a dumb-azz and don't know how to work a microwave (though I might be a dumb-azz)

 

and in the next breath, they want their engineers to look at it when normal procedure is to simply have it field destroyed.

 

So, unit is gone, check in hand and now, we get to go shopping again.

 

:emotion-21:

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