Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!uunet!seismo!ll-xn!ames!sunybcs!kitty!larry From: larry@kitty.UUCP (Larry Lippman) Newsgroups: sci.electronics,talk.bizarre Subject: Re: "Magic Eye" tubes Message-ID: <1871@kitty.UUCP> Date: Thu, 23-Jul-87 23:55:48 EDT Article-I.D.: kitty.1871 Posted: Thu Jul 23 23:55:48 1987 Date-Received: Sat, 25-Jul-87 11:31:41 EDT References: <1495@frog.UUCP> <35ffa63b.b8ab@apollo.uucp> <6@spar.SPAR.SLB.COM> <591@inuxh.UUCP> Organization: Recognition Research Corp., Clarence, NY Lines: 26 Summary: More electronic component nostalgia... Xref: mnetor sci.electronics:1045 talk.bizarre:2620 In article <591@inuxh.UUCP>, rmrin@inuxh.UUCP (D Rickert) writes: > Yup, many years ago I did a lab project in which we used a Decatron > for motor speed control! The idea was for the circuit to keep the > same little dot continuously lit if the motor speed stayed constant > at the set point. A wonderful mix of analog, digital, and power > technology. I think we may have even had a mag amp somewhere in > the circuit (you know, solid state Neanderthal style). Magnetic amplifiers! I haven't run across those gadgets for servo control in years. They came in half-wave, full-wave and push-pull configurations, and were particularly handy for military applications which involved controlling 115 volt 3-phase 400 Hz motors. There is something used for motor control which is even older than magnetic amplifiers - the amplidyne. This gadget was a close-coupled [AC or DC] motor driving an AC generator (often 3-phase) with a DC field coil. Varying the voltage/polarity of the DC field controlled the resultant AC voltage and phase relationship. The amplidyne generator output then drove a servo motor (usually 3-phase). The amplidyne was popular during World War II for controlling search radar antennas (PPI display). Amplidynes were well-described in the MIT "Rad Lab" series - which was still required reading when I got my EE during the 60's. <> Larry Lippman @ Recognition Research Corp., Clarence, New York <> UUCP: {allegra|ames|boulder|decvax|rocksanne|watmath}!sunybcs!kitty!larry <> VOICE: 716/688-1231 {hplabs|ihnp4|mtune|seismo|utzoo}!/ <> FAX: 716/741-9635 {G1,G2,G3 modes} "Have you hugged your cat today?"