Cydrome Leader wrote in
:

Michael A. Terrell wrote:

GS wrote:

On May 14, 8:49 pm, "Michael A. Terrell"
wrote:
mm wrote:

On Sat, 14 May 2011 19:19:28 -0400, "Michael A. Terrell"
wrote:

Magnetrons don't work that way. They run at full power over
their
useful life. That's why they have to use PWM to control the
average power level.

actually,like any other vacuum tube,power output depends on plate voltage
and current. If you lower the plate voltage,the magnetron WILL produce less
power. that's how the inverter ovens work.

But originally,it was too expensive to control plate voltage,so the
manufacturers went for duty cycle operation instead.("pulsed")
You can do that with a cheap relay and timer circuit.

Now,it's cheaper to use an inverter because the heavy iron transformer
costs so much more than a smaller HF switcher transformer,and a switcher
can control it's output voltage.



Makes sense. Okay. I'll give up the plan. That's one more
thiing I don't have to do.

Thanks again.

You're welcome. That's why I have two microwave ovens.

--
You can't fix stupid. You can't even put a Band-Aid? on it,
because it's Teflon coated.

I use two. A big sears 800 watts, and little Panasonic inverter 1200
watts. Weird but true. Always use the inverter for frozen dinners.

I think you have to wide pulse the magnetron, like many seconds.
A little weird, the inverter takes about 3 seconds to fire up after
pushing start.


The Magnatron filament is turned on and off to pulse the output.
It
takes a fraction of a second to warm up.

Some of the older US made units from Litton or Tappan had a giant reed
relay, and the HV was actually switched on and off for the defrost
mode. They made a nice sound switching on and off.


it's cheaper to switch the transformer side instead of the HV side,and the
HV switching probably wears out quicker.

--
Jim Yanik
jyanik
at
localnet
dot com