[AMRadio] Ferroresonant transformer revisited

Mike Dorworth, K4XM k4xm at arczip.com
Sun May 7 13:36:32 EDT 2006

> > How hot is the darn thing -supposed- to get?

For your unit I don't know. I have used hundreds of SOLA Constant Voltage
Transformers, of the 250, 500, 1000, and 3000 watt versions. They were of
the CVH (harmonic neutralized..SQUARE WAVE) and the CVS (SINE wave type).
The 250 watt is impossible to touch in service even with no load. They will
remove skin but will work for over twenty years without fail. The 500
watters and the bigger ones being larger (having more mass) can be touched
but still run warm. What these things were for was to take a voltage of 90
to 140 volts ac and maintain it at exactly 120 volts. We used them for
lightning protection and they worked fine protecting what ever was plugged
in; radio equipment and test equipment in the racks. They all draw current
when not in use and therefor are a waste of electricity unless they are
actually supplying something. Protecting a EIMAC high dollar tube filament
would be a great use. We nailed them to concrete block walls vertically for
convection cooling. I worked with these things 38 years and don't remember
but one capacitor failing in one which was easily replaced and returned to
service. Hope this non-answer helps. 73 Mike

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