[rescue] I want a vacuum tube
newell at cei.net
Wed Oct 29 18:18:23 CDT 2008
At 05:22 PM 10/29/2008, Robert Darlington wrote:
>My buddy's Monarch 10EE lathe uses two big thyratron tubes and several
>others. Very odd seeing that in there, but the tubes are used to rectify
>the 60Hz AC coming in, then use the thyratrons to create a variable
>frequency AC source for the motor. The frequency dictates the speed of the
>motor so it's an old "VFD" or variable frequency drive. Neat stuff and it
>not only works, but it's a production machine in his busy shop.
I'm not so sure...the old ones that I've seen had a DC spindle
motor. The tubes were used to adjust the DC voltage (and the field
voltage) of the spindle motor.
It's a beautiful lathe, BTW. Never been lucky enough to run one. (Yet!)
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