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Re:The Magnetic Amplifier – A Lost Technology of the 1950s by jcims on Thursday June 18, 2020 @12:45AM (#23559866)
So if you wound a 1:1 transformer on a coil that has additional windings to ’preload’ it, could you use this as a speed controller/voltage regulator?
Re:The Magnetic Amplifier – A Lost Technology of the 1950s by segfaultbuserr on Thursday June 18, 2020 @01:13AM (#23559995)
Yes, it's called a saturable reactor [0] and can be considered as a very simple type of magnetic amplifier. You control the impedance of the reactor using the extra winding, conceptually similar to how you control the conductivity of the pass transistor in a solid-state voltage regulator. You can find them in old Tektronix oscilloscopes, here's a long (70 min.) and comprehensive video [1] on the design of the Tektronix 555 power supply, including the operation of the saturable reactor voltage regulator.

[0] https://en.wikipedia.org/wiki/Saturable_reactor

[1] https://www.youtube.com/watch?v=CAbeWXcuYOE

Re:The Magnetic Amplifier – A Lost Technology of the 1950s by jcims on Thursday June 18, 2020 @01:41AM (#23560108)
Awesome thank you!!!
Re:The Magnetic Amplifier – A Lost Technology of the 1950s by phasetransition on Thursday June 18, 2020 @07:53AM (#23562185)
Yes. Saturable core reactors have a long history of industrial regulation of heavy duty motors, furnaces, and the like. I first learned about them from old cranes in seaports.

For some applications size and weight aren't a big deal, but durability and overload tolerance are, so I can imagine they are still used out there somewhere.