• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Microwave cooker modulation

Nigel Goodwin

Super Moderator
Most Helpful Member
#21
Hi again,

No problem.

That's interesting that the oven powers are limited over there. I have to wonder why that is so.
That's the power that standard magnetrons provide - as I said I've never heard of higher power ones - possibly yours is quoting the power consumed from the mains, rather than the actual RF output?.

Yes we only have 120vac here so it's not as good. I wish that they started using 230vac long ago. Looks like we are stuck with it.
We're actually 240V in the UK, the 230V rating (for the EU) is for equipment specifications and must cover the UK's 240V and the rest who are 220V.
 

MrAl

Well-Known Member
Most Helpful Member
#23
That's the power that standard magnetrons provide - as I said I've never heard of higher power ones - possibly yours is quoting the power consumed from the mains, rather than the actual RF output?.



We're actually 240V in the UK, the 230V rating (for the EU) is for equipment specifications and must cover the UK's 240V and the rest who are 220V.

Hi,

Well the input current is over 15 amps i think it's 16 amps, and 16 times 120 is 1920 watts input power. With 1200 watts cooking power that is about 62.5 percent efficient which is about right. My older oven only drew much less current on high from the wall and that was known to be a lower power unit. When i turn this new oven down to power level 3, it draws around 6 amps from the wall, so i know it has to be lot higher power than the old oven.
How they do this i dont know, but i never heard of a limit on the power of a magnetron, that they could never design one over 700 watts or something like that. I might note that i read about them being able to get much higher. I dont think they are using two in this oven, but i'd have to take it apart to find out for sure.
I also did a test when i first got the oven and it boiled 8 oz of water in something like a minute or a minute and a half, which is quite fast. Cant remember the exact time now though.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
#25
How they do this i dont know, but i never heard of a limit on the power of a magnetron, that they could never design one over 700 watts or something like that.
I'm certain you can buy magnetrons FAR higher than the standard ones used in ovens, after all they were invented for radar applications.

As I mentioned previously, all the commercial ovens I've repaired simply used two magnetrons to give double the power though, and didn't use any 'unusual' magnetrons.
 

MrAl

Well-Known Member
Most Helpful Member
#26
I've never known a microwave to regulate power other than by adjusting its duty cycle - seconds per burst, rather than bursts per second.
Hi,

Most of them do that, but then Panasonic came out with their line of "inverter ovens" that use a inverter to regulate the power in a way that does not need pulsing. This means the actual power level goes down so the input current geos down too. Not just the average current, but the instantaneous current goes down so it gives a continuous cooking power rather then a pulsing cooking power.
If you measure the input power to a regular oven it will go from every low to very high, then back to very low, then back to very high, etc., on the lower cooking levels. That way it obtains an average cooking power that is less than full power.
 

davenn

Active Member
#30
To match the output of the magnetron, the cavity of the oven is designed to give such a match.

Like any transmitter you can't just use it without an aerial, it will destroy the transmitter - and not work well either.

though, you would be surprised how well a transmitter works straight out the end of a length of tuned waveguide :)

edit, I have done that on 10 and 24 GHz quite successfully
 

davenn

Active Member
#31
I can think of 500-600 reasons why this is a bad idea...
and yet you couldn't even give me one or two reasons

you DO NOT want to be using that sort of power level or a terrestrial point to point, you will cook ( pun intended) people and other living organisms

the only real valid reason for that much poser would be for doing amateur radio moon-bounce.
 

throbscottle

Well-Known Member
#32
Yes we only have 120vac here so it's not as good. I wish that they started using 230vac long ago. Looks like we are stuck with it.
I thought you guys had "bi-phase" mains power, so you could get 240v for electric ovens. Although I suppose running plug in appliance with 2 live wires isn't a good idea...
 

throbscottle

Well-Known Member
#35
Huh? You talking about site transformers? CTE... But the difference is it's 55v live, not 115v. A lot less deadly :/
 

GromTag

Active Member
#36
A moon bounce signal.... Hmmm, lets see here, just watch out for space debris that might bounce the signal somewhere else and turns some ones house into a popcorn bash party. And 2, be sure not to hit those really expensive Geminids, Leonids, or Orionids Sattelites. Might be charged a big bill to replace those gems.... :hilarious:

The Wifi use, the signal would have to ride the wave at some point during its stable points as most Magnetrons can self resonate unless cranked up in frequency. As far as I know on that.
 

Latest threads

EE World Online Articles

Loading

 
Top