On Sat, 03 Nov 2007 11:46:08 -0700, terry wrote:

Proposing to scrap some microwave ovens. What uses are there for the
power transformers? Apparently these have 115 volt primaries and HV
windings upwards of 2000 volts AC RMS.
Their power handling capacity must be of the order of 900 to 1000 VA
(volt-amps or watts)?
1000 VA at 2000 volts indicates something of the order of 0.5 amps! Wow;
0.5 amps even at say 230 volts indicates 115 watts or thereabout and the
secondary (the 'old' primary) providing about 12 volts or thereabouts at
around 10 amps or so, provided one has a 230 volt outlet available?
Any good (connected backwards) as a battery charger? Ideas/criticism
welcome.

I have seen two different designs for linear amplifiers, using microwave
oven xfrms in the HV supplies. One of the designs even removes the HV
secondary, and rewinds the transformer for the LV filiments.

Hooking them up backwards is most likely a very bad idea, as most oven
transformers have one side of their secondary tied to the core. Never a
good idea to hook up mains to such a design, due to risk of electrical
shock.