Reduce power of a microwave oven?

Can you return the oven? You can use the argument that it's not fit for its intended purpose. Which it isn't.

I always assumed variable power was simple duty-cycle variation -- pulse-width-modulation -- over a fraction of a second. That the "on" time would be fixed at 15 seconds (!!!), with the off time varied, is absurd. It would produce exactly the effect you see.

There's also the possibility your sample is defective.

The stuff at the bottom of a microwave-popcorn bag is called a susceptor sheet. I think it's a ferrite material, but I'm not sure.

Without any food to absorb heat from the susceptor, it would probably overheat and burn fairly quickly.

You might try putting a brick on the oven, on the remote chance fire-hardened clay absorbs microwaves. Bricks made with metallic colorants might be the best place to start.

RTFM to see how to set the cook power.

Amazing!!! RTFM reply when I stated EXACTLY how the power setting works. How about RTFOP?

Nope, my inability to forecast the consequences is not the fault of the seller.

Yep, that's the way most of 'em work. The problem is the filament in the magnetron. Much shorter and you don't get any power out cause the filament ain't hot yet. With enough mass inside the oven, it averages out pretty well. For a single frozen hamburger at 1100W, not so much.

Yes, you can buy a microwave with fine-grained setting of continuous power at most any retailer...for 3X the price. They have to keep the filament hot while reducing the power. Much more complicated and not a commodity item >> much higher price.

They used to make browning plates with some kind of susceptor in the bottom. Seems the only place you get 'em today is from TV infomercials at high prices or on ebay at antique prices.

I do have a microwavable trivet that claims to be made from granite. Gets hot alright, but it's encased in plastic and not well coupled to whatever you put on it. A couple of experiments suggest that while it does divert significant power, it will probably overheat trying to do what I want.

A cup of water solves the problem, but it's not very elegant.

There's considerable range of microwave absorbency. I was hoping to find some kind of commonly available ceramic, like floor tile, that would work. That's why I asked for input. Wonder what Home Depot would think if I packed tile samples into the employee lounge and stuffed 'em into the microwave?

On 1/18/2011 5:55 PM mike spake thus:

Mr. Terrell apparently shoots from the hip and never apologizes.

Not that much higher these days, I think. The Toshiba "inverter" microwave ovens have a variable power level of this general sort, and they're commodity items to the extent of being buyable at Costco and probably other big-box stores. They're somewhat more expensive than ovens fixed-power magnetrons, but not all that much.

However... I had one, and it died within a couple of years in home use. Our previous microwave had lasted for a couple of decades. I'm not sure whether this was an odd failure in this unit, or was characteristic of Toshiba inverter microwaves in general, or just an result of the "race to the bottom, in price and in quality" which seems to be affecting the whole consumer-electronics business these days.

I bought a fixed-power-output commercial-service Amana as a replacement, in the hopes that it'll last rather longer than the Toshiba did.

Mike-

Does the new microwave have a Defrost option? If so, does it also cook for 15 seconds at full power?

I had a small microwave back in the 70s that had a low power setting. My memory is a little hazy, but I think the low power setting switched a capacitor in series with the high voltage transformer primary. It acted as a ballast to reduce magnetron voltage.

Fred

Your easiest solution may be to look for a new model that has the cooking power levels that suit your needs. I haven't looked at MWOs lately, but the revolving turntable should probably be a major consideration.

From many years ago, I found that trying to cook numerous types of foods in a microwave provided awful results, and never bothered to try them in more advanced models. Bacon, eggs, burger were some examples.

The fairly large MWO I use now was given to me a number of years ago, and suits my needs for the types of foods that I want to be microwaved. The manual has so many different types of cycles, that I don't even bother to try to remember them. I stick with the basic operations, which limits what the MWO will be used for, but that's not a problem for me.

Typical MWOs aren't a good substitute for an actual range/stove (and appropriate cookware, talent, time etc). Also, one generally needs to find the types/brands of processed foods that provide the user with something desirable to their own tastes.

The top crust of a pot pie should be browned.. the Marie Callendar(?) frozen pies have a metallic grid made into the top of the box, and the crust always browns (may not work with low-powered MWOs, I don't know for sure). The minimum power recommended is marked on the box. The 1 lb size pies are a decent portion, and taste good.. allow ample time for cooling.

I don't have them anymore, but at one time I had a set of microwave dishes with covers that were very useful. They were a tan bakelite/melmac-type material with metal flakes visible in the material.. they were a fairly common brand name in the U.S. but I'm not sure what it was. Anyway, I could get varied results with lid on , off or turned 45 degrees (square dishes), which are all common techniques with conventional cooking. So, the types of accessories and different techniques will yield more options, and very different results.

I've found certain techniques that produce results which are more to my personal liking.. such as always wrap/cover a sandwich in paper towel to heat (prevents the bread/bun from getting hard spots without becoming soggy), cover cold pizza also with paper towel, or better yet, eat it cold. There are various options.. placing flat foods between two paper plates, or tall sandwiches between two paper bowls. There are various commercial plastic products/accessories for MWO use, but those require washing.. disposable paper (not plastic/styrofoam) plates and bowls, and plastic utensils don't.

I never put uncovered liquids or other types of foods that are a combination of food/liquid in the MWO, I always use a paper plate as a cover. I can't stand seeing a dirty MWO, and it's far easier to prevent eruptions than to clean them up. But then, I generally always wipe the interior down with a paper towel dampened with 60/40% water/alcohol mixture that has a few drops of liquid soap added per pint, to wipe out the condensed moisture, every time I use the MWO.

-- Cheers, WB .............

Or use the defrost cycle!

If your description is correct, the oven is grossly misdesigned. You do not implement variable power by turning the magenetron on for 15 seconds, then letting it sit for a minute! I've /never/ seen a microwave oven that works that way. My home GE works fine, as do all those I've seen where I've worked.

It

I've never heard of varying a magnetron's power by adjusting its filament voltage! I've always ASS+U+MEd there was some way of turning the tube on and off by varying an electrode voltage. (Simply pulsing the anode voltage would produce variable output.)

A microwave oven is ideal for bacon, because all it needs is a thorough heating. Which is all a microwave oven does... It doesn't actully /cook/ anything.

Many new microwaves have and auto-defrost function (also usually an auto-reheat) that measures the humidity while firing the magnetron for short bursts. It runs this cyclically for a preset time based on your food selection and weight while it calculates the actual time it should take to defrost the food. Then it usually beeps once and finally runs the defrost cycle that it calculated.

I find this works quite well once you get the hang of it.

All of the bog-standard microwave ovens that I've owned have worked exactly like that - and it was fine when they were the 'standard' 600 or 650 watts of a few years ago. However, now they are all 850 / 900 / 1000 watts, it's a crap system of power control. The one I have at the moment, does exactly as the poster's does when set to say 60% power. It's like 15 seconds on at full chat, followed by 20 seconds at full off. 60% is what's needed for heating a can of soup in a reasonable time to a reasonable temperature. And it's ok if it's just a full liquid soup like say tomato. But as soon as you try to do it with anything like perhaps vegetable, 15 seconds of microwaves at 850 watts, is enough to start exploding the peas or beans or barley grains, all over the inside of the rotten thing. 600 watts didn't used to do this. If you go to the next step down - ie 40% power - it takes forever to get the bulk liquid of the soup up to an edible temperature.

Arfa

I seem to remember that we had this discussion once before some years back. It depends on how you define the word "cook". Using the traditional definition of 'preparing food by use of heat' I would contend that this is exactly what a microwave oven does - or am I missing something ... ? If I am, then what *is* cooking that a conventional oven does differently ?

Arfa

exactly

as

full

if

all

Fascinating. (In the correct Spock sense... "Fascinating I reserve for the unexpected.")

I have a high-power GE microwave oven cum exhaust hood. Many foods -- such as soup or oatmeal -- must be heated at half power (give or take), or you get localized boiling, sometimes very quickly. I've never seen this happen with reduced power. The oven always acts as if the magnetron is being rapidly pulsed.

May I publicly apologize for believing that manufacturers ever use the least bit of common sense when designing products?

Your perfectly logical definition seems sufficiently generic to include microwave ovens. In practice, "cooking" refers to either immersing the-thing-to-be-prepared in a cavity full of hot air...

"Yeah, Sommerwerck -- yer mouth."

...(baking, roasting) or applying heat directly to it (frying) or from a nearby source (broiling, grilling). Microwave "cooking" does none of these -- it simply heats the-thing-to-be-prepared from the inside.

Oddly, the Wikipedia article claims that microwave cooking heats food more evenly than any other method, when, in fact, it heats from the outside in, as does every other cooking method, and can be extremely uneven, if part of the dish is sitting in a standing-wave node.

Here, for example, is a patent for pulsed control of microwave-oven power. It was filed for in 1975.

let's face it, most cooking is just heating.

Huh? Virtually all the ones I've seen do just that: run a 10 to 15 second on/off time cycle. The magnetron is turned on with a relay, so rapid cycling just begs to blow that relay.