In message ,
(Andrew Gabriel) wrote:

In article ,
Pete C writes:
On Thu, 14 Jul 2005 17:38:35 +0100, Martin Angove
wrote:
An interesting statement that. Of course you are aware that 1000W
microwave output usually translates into about 2000W absorbed energy, in
which case, presumably the "full size" US units you refer to have to be
specially catered for rather than just plugged into a standard circuit?

Sounds a bit unlikely, a 1kW microwave at 50% efficiency would also
generate the same heat as a 1kW fan heater! That would require a lot
more ventilation than they appear to have.

Original magetrons were only 50% efficient.
Over the last few years, I think this has improved,
but there was also a change in the way microwave
output power was measured, which makes them look
better than they used to look, for no actual change.

The waste heat comes from the magnetron, and in
simple (non-combination) ovens, it was often blown
through the oven compartment to help with the food
heating.

I've met quite a few nukes in my time, and I have to say that when you
compare the ratings plate (which for legal reasons has to be pretty
accurate about the absorbed power) with the declared power output, the
ratio is usually quite close to 2:1. I'd love to meet one of these
supposedly 80% efficient devices though.

Do they have ratings plates in the US?

Whether or not a 50% efficiency is going to be noticeable really depends
on the type of use the oven gets. 60 seconds spent heating a cup of
cocoa, even with 1kW dissipated as "waste" heat isn't going to be very
obvious. Last time I had our (850W output) oven on for 5 minutes (doing
a couple of bowls of supermarket-takeaway rice) it did get quite warm.
There's definitely a fan in there somewhere...

Hwyl!

M.

--
Martin Angove: http://www.tridwr.demon.co.uk/
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