Term: Mag Amp

"Ian W. Wright" wrote:

> From: "Ian W. Wright" <Ian@...>
>
> Sorry to seem so dim but what, pray, is a mag amp?
>
> > The trick Bridgeport uses (pretty tricky, but not original) is to use a mag
> > amp on the AC input to the rectifier.

Sorry, old technology. Mag amp is short for a magnetic amplifier.
This goes back to WW-II, and certainly Korea.
A way of getting a lot of gain without much energy loss is to use a winding
of many turns of fine wire to drive an inductor into and out of saturation.
When the inductor is saturated, AC current passes through a winding
of a modest number of turns of heavy wire fairly easily. When the control
winding does not saturate the inductor, then the inductance blocks the
power flow through the power winding.

Jon