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Old December 29th 18, 06:46 PM posted to alt.home.repair,uk.d-i-y,alt.electronics,alt.sci.physics
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Default Slow microwave ovens

On Sat, 29 Dec 2018 18:25:56 -0000, wrote:

On Saturday, December 29, 2018 at 1:06:23 PM UTC-5, William Gothberg wrote:
On Sat, 29 Dec 2018 17:57:35 -0000, Bill Gill wrote:

On 12/29/2018 11:34 AM, William Gothberg wrote:
On Sat, 29 Dec 2018 16:56:35 -0000, trader_4 wrote:

On Saturday, December 29, 2018 at 11:27:53 AM UTC-5, William Gothberg
wrote:
On Sat, 29 Dec 2018 14:23:37 -0000, Bill Gill wrote:

On 12/29/2018 7:43 AM, William Gothberg wrote:
Shouldn't we have faster microwaves by now giving out a few kW? They
were invented decades ago.
Higher powered microwaves would require higher powered electric
outlets, probably 220VAC (in the USA).

Not a problem in Europe where everything is 240V. Another reason you
ought to stop that low voltage crap! Do you seriously have to hard
wire all your washing machines, dishwashers, tumble dryers, etc,
etc? And what on earth do you do with hoovers?

No. Of those only a dishwasher is hardwired, typically. The rest are
plug
and cord, 240V in the case of electric dryers. Works for me.

So you do have sockets where you can plug in 240V 3kW devices, just like
in the UK. So no problem with a more powerful microwave then.
If you don't mind going to the garage/laundry room/etc. to use your
microwave.


In the UK we don't have that problem, my kitchen is full of 13A 240V sockets, just like every other room, it's what I plug my kettle, dishwasher, washing machine, bread maker, etc, etc into. All of which would be utterly useless on a 120V circuit. I thought the USA had 240V sockets in rooms where they're likely to be needed, like the kitchen? And where do you plug in a 2kW hoover? I plug mine in any room I'm hoovering.


If there's a 240V socket in the kitchen, it's quite likely behind the stove,
which is plugged into it.

I wasn't conveniently able to find the power consumption of my vacuum
cleaner, but I'm sure it isn't 2 kW. My floors are hardwood, so that
kind of power isn't required.


1kW hoovers are ****, especially if you have pets or carpets.

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Old December 29th 18, 06:47 PM posted to alt.home.repair,uk.d-i-y,alt.electronics,alt.sci.physics
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Default Slow microwave ovens

On Sat, 29 Dec 2018 18:27:21 -0000, Arthur Conan Doyle wrote:

"William Gothberg" wrote:

Why is it called an invertor?


Typical microwaves use fixed AC power to drive the magnetron. Inverter driven
magnetrons use DC power, which can be variable.


So they rectify the AC, then boost the DC voltage as required by the user setting?

But even without an invertor, surely you could have a few tappings on a transformer to change the AC voltage to the magnetron? It's not like you need infinite control, just 3 or 4 would do.
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Old December 29th 18, 06:51 PM posted to alt.sci.physics,uk.d-i-y,alt.home.repair
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Default Slow microwave ovens

On Sat, 29 Dec 2018 18:45:47 -0000, rbowman wrote:

On 12/29/2018 06:43 AM, William Gothberg wrote:
Shouldn't we have faster microwaves by now giving out a few kW? They
were invented decades ago.


I worked for a company around 1970 that developed a few high power
microwaves that were placed in area restaurants. The idea, now
completely familiar, was the restaurant could prepare quantities of
food, freeze them, and thaw on demand. Other companies had similar
industrial ovens.

The core business of the company was industrial plastics preheaters
which functioned at around 100 MHz rather than microwave frequencies.
They completely missed the consumer microwave market that was to grow in
the later '70s.

We always had a couple of the smaller preheaters hanging around
engineering. They did wonders for stale donuts. Even the factory workers
in the molding plants caught on. 'I bet if that thing can heat a
phenolic biscuit to 300 degrees it would work on my sandwich.' We didn't
explicitly mention it when installing new equipment other than vague
cautions about not putting aluminum foil in the cavity. The larger
models were 15 KW and could generate some Tesla quality fireworks.


I've watched countless Youtube videos of people abusing microwaves. The funniest one was a teenager who thought it would be a good idea to microwave one of those chemical lights - the ones you shake and they glow green. It exploded and got him in the eyes, followed by his father yelling "I told you not to do that!". I fell off my chair laughing.

As the various RF technologies like heat sealers made it to the
workplace a whole folklore grew up. Working around them could either
make you sterile or incredibly fertile, take your pick.

The technology has been around for over 50 years. What you find at Tesco
is what sells.


I'm surprised people aren't going for "super fast microwave, cook your meal in 5 minutes" varieties.
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Old December 29th 18, 06:52 PM posted to alt.home.repair,uk.d-i-y,alt.electronics,alt.sci.physics
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Default Slow microwave ovens

On Sat, 29 Dec 2018 18:48:38 -0000, trader_4 wrote:

On Saturday, December 29, 2018 at 1:21:48 PM UTC-5, Arthur Conan Doyle wrote:
"William Gothberg" wrote:

Anyway, I've never used a microwave on anything other than full power - even when defrosting, which for some reason people think you have to select "defrost". Why? It just takes longer. I can defrost food much faster on full power.


The idea is not to cook the food as its defrosting. Full power is fine if you
want the end item hot. It's not good if you want something room tempurature or
slightly cooler to use as a part of preparation of something else.


+1

I already tried to explain that to him with my frozen tomato sauce example.
You put a quart plastic container in the microwave and even on the defrost
setting, where it runs at like 30% power and also pulses that on for maybe
75 secs, then off for 20 or so, the bottom gets hot to the point that the
plastic container can start to soften, while the upper portion is still
frozen solid. You're right, defrosting meat is an even better example.
You'd be cooking part of it while the rest is still frozen. It already
happens with the current ovens, if you're not careful.


Microwaving something in a cheap **** plastic container is insane. I always cook or eat things in a real pot bowl. Plastic melts!
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Old December 29th 18, 06:53 PM posted to alt.home.repair,uk.d-i-y,alt.electronics,alt.sci.physics
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Default Slow microwave ovens

On Sat, 29 Dec 2018 18:50:02 -0000, trader_4 wrote:

On Saturday, December 29, 2018 at 1:45:03 PM UTC-5, William Gothberg wrote:
On Sat, 29 Dec 2018 18:21:45 -0000, Arthur Conan Doyle wrote:

"William Gothberg" wrote:

Anyway, I've never used a microwave on anything other than full power - even when defrosting, which for some reason people think you have to select "defrost". Why? It just takes longer. I can defrost food much faster on full power.

The idea is not to cook the food as its defrosting. Full power is fine if you
want the end item hot. It's not good if you want something room tempurature or
slightly cooler to use as a part of preparation of something else.


Then I just use less cooking time. Full power will defrost to room temperature much faster than that pointless defrost mode. And if you're about to say it won't be even, so what? If it's for part of preparation of something else, it has plenty time to even out.


The so what is that the plastic container will melt or part of the meat
will be cooked via steaming, instead of being able to make it into a
burger and grill it. Capiche? No, of course not.


I don't seem to have that problem, full power defrosts things evenly enough. Some bits are probably a bit hotter than others, but it's evened out by the time I eat it.


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Old December 29th 18, 06:53 PM posted to alt.sci.physics,uk.d-i-y,alt.home.repair
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Default Troll-feeding Senile IDIOT Alert!

On Sat, 29 Dec 2018 17:15:05 +0000, Bill Wright, yet another braindamaged,
troll-feeding senile idiot, blathered:


Conduction


Yes, senile idiot, even a single-word feedback helps the troll to keep going
and going.... ****ed up stupid seniles! tsk
  #47   Report Post  
Old December 29th 18, 06:55 PM posted to alt.sci.physics,uk.d-i-y,alt.home.repair
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Default Troll-feeding Senile YANKIETARD Alert!

On Sat, 29 Dec 2018 12:00:47 -0600, Bill Gill, another brain damaged,
troll-feeding, senile Yankietard, blathered:


1200 watt consumer microwaves are widely available. Check your
Walmart or whatever you have.

Bill


Yeah, KEEP feeding the retarded Scottish attention whore ...and see what you
get for it! LOL IDIOT!
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Old December 29th 18, 06:57 PM posted to uk.d-i-y
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Default Slow microwave ovens

Brian Gaff wrote

I am not sure what you mean.


He wants a higher power microwave that heats
say a cup of water in less time. Trivially buyable.

You can also get commercial microwaves that
have two magnetrons put a lot more microwaves
into want is being cooked to cook it faster.

Surely the speed of heating depends on the absorption of the energy by
what is inside the machine.


But that depends on how much microwave power the
magnetron is putting into the oven chamber itself.

He's talking about cooking food or heating water.

If its not high enough in things that can get hot, like water content, you
can cook it as long as you like with little effect at all.


"William Gothberg" wrote in message
news
Shouldn't we have faster microwaves by now giving out a few kW? They
were
invented decades ago.


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Old December 29th 18, 07:00 PM posted to alt.sci.physics,uk.d-i-y,alt.home.repair
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Default Slow microwave ovens

On 12/29/18 7:43 AM, William Gothberg wrote:
Shouldn't we have faster microwaves by now giving out a few kW?* They
were invented decades ago.


Pretty much the same reason one doesn't always turn a conventional
oven up to broil. 350 F. is a pretty common setting if my memory is
working.
T4 has a good example.
It comes down to lack of demand.
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Old December 29th 18, 07:02 PM posted to alt.home.repair,uk.d-i-y,alt.electronics,alt.sci.physics
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Default Slow microwave ovens

In article ,
"William Gothberg" writes:
On Sat, 29 Dec 2018 17:38:04 -0000, Clare Snyder wrote:

On Sat, 29 Dec 2018 08:07:42 -0800, Bob F wrote:

On 12/29/2018 6:37 AM, trader_4 wrote:
On Saturday, December 29, 2018 at 9:23:42 AM UTC-5, Bill Gill wrote:
On 12/29/2018 7:43 AM, William Gothberg wrote:
Shouldn't we have faster microwaves by now giving out a few kW? They
were invented decades ago.
Higher powered microwaves would require higher powered electric
outlets, probably 220VAC (in the USA).

Also it is questionable whether higher powered ovens would be
practical for use. Getting warming times down to a couple of
seconds might not be a good idea. More speed is not always better.

Bill

+1

That about covers it. Not sure how useful more power would be. For example,
last night I was thawing out a tomato sauce in a quart plastic container.
The Panasonic has a defrost mode that uses about 30% power and cycles that.


It gets the 30% power by cycling the 100% power on 30% of the time.

(By the way, adjusting the level does not actually change the wattage.
It simply means the microwave will pulse on and off at its fixed wattage
until the desired level is reached.)

https://lifehacker.com/5974788/famil...-cooking-a-joy

That was true of the first generation of Microwaves, but the current
"inverter" driver units actually CAN throttle the power. Inverter
microwaves are much better for defrosting AND cooking.

We've had ours for about 2 years now - replacing our original that we
bought in about 1985.

BIG difference (but the old one would likely still be working by the
time this one dies)


Why is it called an invertor? I thought an invertor was a device to increase the voltage - like running 240V devices off a 12V car battery.


To run a 5kV magnetron from 240V.

And why on earth would you not want to cook on full power? I've never had a reason to lower the power from the maximum of 800W. I want the meal as soon as possible!


Microwaves do not penetrate all the way through larger volumes of
food - the heating is done in the outer 1-2cm. Heating the middle
is done by conduction (and by convection if the food is a fluid).
If you pile in energy faster than it can conduct all the way through,
you will have a burned outside and a cold middle.

Domestic microwave food products are not designed to be heated in
2kW ovens. Many would fail to cook properly/safely.
Commercial microwave food products (some anyway) are designed to be
heated in 2kW microwaves.

And in reference to your other post, it's not simply a matter of
dividing the cooking time by two. The amount of energy absorbed by
a food product also depends on the surface area exposed to the
microwaves (1 pea in a 2kW oven will not absord 2kW), so the cooking
time in a 2kW oven depends on the size and shape of the item - it
would have to be calculated by the manufacturer and included on the
packaging, but in practice, most domestic food products will not have
sufficient heat conduction to be able to absord 2kW and cook properly.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]


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