Worlds Weirdest Microwave Oven, From A Weapons Factory - The Husqvarna Cupol

[Mads Barnkob]

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Teardown of a 1970’s Microwave Oven from Husqvarna. The model “Cupol” was a iconic design from the Swedish designer Carl-Arne Breger.

Additional information and pictures of the Cupol Microwave Oven and its designer.
https://digitaltmuseum.se/021026355944/mikrovagsugn-for-metaller-och-elektronik
https://www.minnenasjournal.nu/carl-arne-breger-designer-mr-plast-han-med-hinken/
http://blogg.tekniskamuseet.se/raceforarens-mammas-mikrovagsugn/
https://es.wikipedia.org/wiki/Horno_de_microondas#Historia_del_horno_microondas
https://www.flickr.com/photos/lunar-1/29857467730

[MRMILSTAR]

Very strange oven, Mads. The usable heating space is not very much. That transformer looks very interesting. I wonder if it has more iron in its core than a modern MOT?

Its funny how various international companies are perceived differently in different countries. I have been riding motorcycles for 50 years. Back in the 1960s and 1970s, most people here in the USA thought of Husqvarna as a company that made off-road motorcycles for motocross. That was the perception here in the USA then but even today I think "dirt bikes" when I hear "Husqvarna". From your posting it sounds like Husqvarna is perceived primarily as a weapons company in Denmark. Of coarse I now know that Husqvarna makes many different products but I never knew that they made a microwave oven.

[Mads Barnkob]

It is a very old Swedish state owned company, from 1689 they make riffles and kept doing so for 300 years. Closed down in 1989.

But among weapons, they also did kitchen appliances, bicycles, motorcycles and power tools.

Their history in brief: http://www.husqvarnagroup.com/en/history-timeline#!/p/215

The C-core transformers are rated for full operation at given current, not like today's undersized MOTs with aluminium wires. I also took apart a Husqvarna model 106 industrial kitchen microwave oven and it had a 4 kVA C-core transformer that weighed 14 kg. You can see that here:

[klugesmith]

Until this thread came along, Husqvarna made me think of chainsaws. 
A very respectable brand, in a class with the one in this funny commercial (skip to 0:20).

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After we had to scrap my wife's old Peugeot automobile, I got her a Peugeot peppermill.

[shrad]

they are known by their mowers and chainsaws here

[johnf]

The two rectangular wire rectangles are probably skeleton slots (similar to stripline slots with most of the extra material removed
These are resonant circuits and probably aid evening out the field in the dome
would be interested in the dimensions and i'll try to calculate the res feq

[Mads Barnkob]

The two rectangular wire rectangles are probably skeleton slots (similar to stripline slots with most of the extra material removed
These are resonant circuits and probably aid evening out the field in the dome
would be interested in the dimensions and i'll try to calculate the res feq

I can not locate it right now, I am not sure where I put it. But a user on youtube commented this:

headshoter 2 weeks ago (edited): Well the dimensions of the rectangles seems to be tuned to 2450 mhz so.. yes its an antenna.

headshoter 2 weeks ago: @Kaizer Power Electronics i'm not much into rf, but taking in count each rectangle is 1/2 wavelengh by 1/4 wavelength and both rectangles are separated 1 wavelength from eachother and both grounded, i guess the purpose is to reflect the wave 180 degrees so it cancels the incoming waves into the magnetron. please someone more experienced on this tell me if i'm wrong.

[klugesmith]

Very interesting about the slot dimensions.  Reminds me of 1980-era household MWO's whose magnetron output was launched conventionally into a rectangular sheet-metal waveguide, that led to the cooker box port.

For benefit of newbies, at the risk of preaching to the choir here:
2450 MHz is not any special resonant frequency in water or food.
Among frequencies that could do the job about as well, with similar costs and sizes and weights,
2450 is in a section of RF spectrum allocated for ISM use (and only incidentally for telecommunication, e.g. wi-fi).