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Author Topic: Why aren't microwave ovens becoming more powerful?  (Read 12539 times)

Offline Dan Williams

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Dan Williams  asked the Naked Scientists:
   
Hello. I listen to your podcast every week and it's great!
I have a question and I wonder if you would feature it on your program.

Why is it that domestic microwave ovens are not being manufactured with ever increased power, and therefore in turn much faster cooking times? It seems that microwave ovens have peaked at around 1000 watts. Is it that foods that are cooked using extremely high power microwaves do not have a good texture? Will the day ever come when you shove a frozen chicken in the microwave and 10 seconds later it is cooked?

Many thanks.
Dan from Inverness

What do you think?
« Last Edit: 06/02/2011 17:30:04 by _system »


 

Offline Pumblechook

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Why aren't microwave ovens becoming more powerful?
« Reply #1 on: 06/02/2011 17:39:54 »
A high power oven wouldn't cook as well. A longer cooking time means that the centre of the food is more likely to reach the required temperature over a reasonable length of time.   2kW is probably the limit from a domestic 3kW (13Amp) socket with efficiency of around 66%.

 

Offline CliffordK

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Why aren't microwave ovens becoming more powerful?
« Reply #2 on: 06/02/2011 22:36:05 »
I do 100% of my cooking on "high".
Although I'm not sure I would want a higher setting, although perhaps one could make a "smart" microwave.
Add IR...
And one could say adjust the setting to cook at 100°C, for example.
Quick heating to 100°C (or whatever your set point is), then maintenance.

Here in the USA, most microwaves are wired for 120V, 15/20A.  So that limits the power.  I've always wired the microwave on an independent circuit so it would be easy enough to swap to 240V (some are now availble at 240V).  However, for some people it would require an electrician, and would only be possible to easily make the swap for microwaves on a dedicated circuit.
 

Offline microwaveguru

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Why aren't microwave ovens becoming more powerful?
« Reply #3 on: 07/02/2011 18:04:54 »
The limitation is the 15 or 20 Amps lines in most kitchens. Since a magnetron is only ~ 50% efficient, and we use 120 volt AC, there simply isn't enough amperage in kitchens. Higher wattage magnetrons are available, but they can't compete cost-wise with home oven magnetrons that sell for $ 8 to $ 10 each.
 

Offline SeanB

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Why aren't microwave ovens becoming more powerful?
« Reply #4 on: 07/02/2011 18:20:56 »
You could get microwaves that had 2 magnetrons, and there are commercial units that use up to 8 magnetrons to reduce cooking times for large commercial preparation areas that have to deal with large volumes of food at a time. Would not work well at a domestic level, it is generally best for cooking a whole lot of the same, where you want a fast cooking time,. and where you are sure the energy will reach the interior of the food, as microwaves still only penetrate the outer part of the food, the rest cooking by conduction.

If you want faster cooking a microwave of higher power just increases the risk of burning the outer layer whilst leaving the inside underdone.
 

Offline Bored chemist

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Why aren't microwave ovens becoming more powerful?
« Reply #5 on: 07/02/2011 22:08:36 »
Just a quick question to those who say that there's not enough electrical power to run a higher power microwave; how do you run an ordinary electric oven?
 

Offline CliffordK

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Why aren't microwave ovens becoming more powerful?
« Reply #6 on: 08/02/2011 00:36:44 »
Just a quick question to those who say that there's not enough electrical power to run a higher power microwave; how do you run an ordinary electric oven?
In the USA, typical "new" construction is with a 200A, 240V main. 50A, 240V for the stove with 6AWG wire.  Your typical household wiring is 12AWG (20A), or 14AWG (15A).

It is not that you couldn't run new wire...  and run a 50A, 220V microwave, however, most microwaves are being sold as countertop appliances.

If you push 50 amps into your microwave, you will have serious heat dissipation issues too.

Some of the new tankless HW heaters suck down a lot of amps.
many take twin, 240V, 40A circuits.  I see a couple advertised that require 3 - 240V, 40A circuits.

So, retrofitting is not as much power, as it is convenience and marketing.

Also, note that many older homes, especially if they use Natural Gas, have 100A mains.
 

Offline CliffordK

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Why aren't microwave ovens becoming more powerful?
« Reply #7 on: 08/02/2011 00:43:31 »
When I worked in a furniture factory for a brief period of time, they used a "RF" machine as part of their lamination.

They would glue the pieces together.  Shove it into the RF which would then clamp and microwave it (enough wood to fill about 4'x8'.  Within 1 minute, the wood would come out...  tacky...  but stuck together good enough that you could drop it and it wouldn't budge.  I think there was supposed to be some kind of metal catalyst in the glue.

Their On/Off indicator was just a standard fluorescent bulb sitting in a rack near the machine...  nothing connected to the ends, just sitting on a rack.  The emissions were high enough that it would light the bulb.

I imagine you could heat up your lunch with the machine too   ;D
 

Offline Geezer

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Why aren't microwave ovens becoming more powerful?
« Reply #8 on: 08/02/2011 02:37:53 »
When I worked in a furniture factory for a brief period of time, they used a "RF" machine as part of their lamination.

They would glue the pieces together.  Shove it into the RF which would then clamp and microwave it (enough wood to fill about 4'x8'.  Within 1 minute, the wood would come out...  tacky...  but stuck together good enough that you could drop it and it wouldn't budge.  I think there was supposed to be some kind of metal catalyst in the glue.

Their On/Off indicator was just a standard fluorescent bulb sitting in a rack near the machine...  nothing connected to the ends, just sitting on a rack.  The emissions were high enough that it would light the bulb.

I imagine you could heat up your lunch with the machine too   ;D

Tacky! I'll show you tacky...

 

Offline Don_1

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Why aren't microwave ovens becoming more powerful?
« Reply #9 on: 23/02/2011 11:52:30 »
I think you may find that heating the food too quickly would not be such a good idea. For one thing it may not cook properly and for another, it may result in the food exploding rather than cooking.
 

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Why aren't microwave ovens becoming more powerful?
« Reply #9 on: 23/02/2011 11:52:30 »

 

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