On 28 Dec 2006 11:40:12 -0800, wrote:

wrote:
The fan's job is more than cooling the magnetron. The blades of the
fan are used to disperse the microwaves inside the oven to help
prevent cooking hot spots.

How do the blades disperse the microwaves?

The entire chamber is a resonant cavity. The entire space is inundated
with microwaves.

-Mike K.

As a newcomer to this newsgroup, please allow me to clarify.

I do not mean to dispute your information about the stirrer blades, I
agree with you.

I am trying to get more information about what exactly is involved in
the dispersion. More than what I pick up off of the various "how does a
microwave oven work" hits that google returns.

Thank you,

Mike K.

g They are in the path between the magetron and the oven (cavity).
The microwaves reflect off the blades at varying angles (as the blades
turn).

It (the cooking chamber) is not a resonant cavity. To be that it would
have to be rather small (a wavelength of a microwave oven is in the
range of 4 to 5 inches, IIRC). There are 'hot' spots (and cool spots)
in that chamber, caused by reflections, and the interface between the
source and the oven chamber.

This is why if you have a turntable microwave without a dispersal fan
and take out the turntable (or it breaks... g) you can end up with
your dinner over cooked in some places and frozen in other spots.