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| Microwave oven PWM frequency |
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| Zero999:
--- Quote from: ogden on August 12, 2019, 07:32:23 pm ---Microwave is good only at one job: flash heating. It is awfully bad for cooking or defrost. It means all you need - max power. Well... unless you are victim of toxic marketing and truly believe that you can *actually* cook something with microwave. In such case you are lost anyway and regulation of microwave power is least of your worries :) --- End quote --- Well I wouldn't agree with that. Microwaving is the most healthy way to cook certain foods, such as vegetables, because it doesn't excessively heat them or add fat like frying does or require them to be submerged in water which washes out some of the nutrients. The one thing which microwaving doesn't do is brown food. I've just had a microwaved jacket potato and I crisped it up by placing it on top of the toaster for a couple of minutes. |
| soldar:
My German-made induction stovetop has ten settings and at the five upper ones it does seem to regulate the power but at the lower ones it will cycle on and off, like a microwave oven, and it is annoying as hell and makes frying an egg impossible. |
| thm_w:
--- Quote from: soldar on August 12, 2019, 08:58:10 pm ---My German-made induction stovetop has ten settings and at the five upper ones it does seem to regulate the power but at the lower ones it will cycle on and off, like a microwave oven, and it is annoying as hell and makes frying an egg impossible. --- End quote --- What kind of frequency? I have a bosch and it does pulse at the lower power settings but its about 0.5-1Hz or so, perfectly fine for cooking. All pots/pans that I have that work with induction are reasonably thick so buffer the heat, and heat distribution is incredibly even. Maybe something else is wrong here. A typical resistive element heated stove top is much worse, maybe 0.1Hz or lower. |
| soldar:
--- Quote from: thm_w on August 12, 2019, 09:40:34 pm ---What kind of frequency? --- End quote --- I did some measurements. Max power consumed is 1600 W. Then it goes down in 200 W steps down to 1000W. Then from there down it cycles on/off at 1200 W and in the one setting I tried at about T=14 seconds which is unusable for low heat. You can't blast 1200 w for 4 seconds and then switch off for 8 seconds to obtain an average of 400 W. It makes it unusable. Furthermore, even when switched off the thing is consuming 0.7 Amps of reactive power so I have to disconnect it entirely. It's crap. German crap but crap nonetheless. Regarding microwave ovens they are good for reheating stuff and that's about it. I have never used one for real cooking. --- Quote from: thm_w on August 12, 2019, 09:40:34 pm ---A typical resistive element heated stove top is much worse, maybe 0.1Hz or lower. --- End quote --- The resistive plates I have do not switch but even if they did it would not matter much because they have great thermal mass and you can turn them off and the pot will continue to boil for 5 or 10 minutes. I have one that combines three resistor elements in different configurations so I can set from 150 W to 1700 W in six steps: https://www.eevblog.com/forum/beginners/calculating-value-of-resistors-in-parallel/msg2086750/#msg2086750 With resistor elements you can also use a triac power control. |
| langwadt:
--- Quote from: soldar on August 12, 2019, 10:33:10 pm --- --- Quote from: thm_w on August 12, 2019, 09:40:34 pm ---What kind of frequency? --- End quote --- I did some measurements. Max power consumed is 1600 W. Then it goes down in 200 W steps down to 1000W. Then from there down it cycles on/off at 1200 W and in the one setting I tried at about T=14 seconds which is unusable for low heat. You can't blast 1200 w for 4 seconds and then switch off for 8 seconds to obtain an average of 400 W. It makes it unusable. Furthermore, even when switched off the thing is consuming 0.7 Amps of reactive power so I have to disconnect it entirely. It's crap. German crap but crap nonetheless. --- End quote --- get pans with more thermal mass? how much does the temperature change in those few seconds? |
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