[GreenKeys] selector magnet bias

[Duncan Brown]

Jeff -
All the Kleinschmidt machines (except for the TT-4) used selector 
magnets that were like polar relays. Instead of a spring pulling the 
armature away from the pole piece (as done in the TT-4 and Teletype Corp 
machines), Kleinschmidt used a permanent magnet plus an electromagnet to 
bias the armature. This was probably done for faster action of the armature.

Mike - I was at Ft Gordon in 1966 in the TTY repair school.  If you are 
looking for a home for the TT-76 selector mechanism, I'll take it. Can 
always use a spare!

Duncan Brown, K2OEQ
USASA    31J30

Antique Wireless Assoc. Museum,
   Asst. Curator, Commercial Equipment
(also chief TTY op & repairman)

www.antiquewireless.org



On 9/28/2019 20:28, MICHAEL LEWIS wrote:
>
> I missed a lot of the selector magnet discussion, then I was down 
> sizing and ran across a schematic from my teletype school at U. S. 
> Army signal school and found a selector magnet with a bias winding 
> that provided a steady current to the magnet and not in the current 
> loop, selector windings are 120 ohms and the bias windings 420 ohms. 
> reference reperforator-transmitter schematic (TT-76A/GGC) approval 9 
> July 65 . The bias windings have a 5K pot in series with the coils. 
> The system has a switch to change from 60 ma 20 ma depending on what 
> current loop is required. These are all I got left from Fort Gordon, 
> Georgia. probably next stop the recycle box.
>
>
> Mike Lewis KB7KYA
>
>
>
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