[GreenKeys] ASR Motors, etc

[Ralph Irish]

Dave Burns & Group

The 28ASRs typically have a 1/12 HP, 3600 RPM synchronous motor.  28KSRs and free standing TDs
and other items may have 1/20 HP, 3600 RPM motors.  Physically, they are the same.  I was told
that the major difference is in the gauge of the wire used in the windings and the UFD rating
of the Start capacitor.  Amperage will also differ to produce the different horsepowers.  Using
a common 'motor frame and case' cut down on parts inventory and motors could be made to the
needs of the sales of Model 28 equipment.

Essentially, the motors, 1/12 HP and 1/20 HP run at the same speed.  To get different operating
speeds, different gear sets are used.  

I have an ASR that has a 3 speed gearshift that eliminates the need for gear changing if/when
different operational speed is needed.  IN THIS CASE, I DON'T KNOW WHAT GEAR SET IS USED.
The gearshift changes the speed of everything:  TD, printer and reperf.  

I know that George, W7TTY has a lot of experience with Teletypes in a variety of situations,
but I'm puzzled at the idea that the ASR in question will only run at one speed, safely.  A
set of gears will affect the running RPM of all components in the machine, with the possible
exception of the 'dome mount' reperf.  I believe that it has its own motor, but I am not
certain of this.  I have only seen photos of these machines.  

As for LARP and other types of reperfs, I am not going to even offer a guess as to whether
the LARP is the only one in use in 'dome mounts'.

The limited Delta Airline ASRs from the mid to late 1960s had an 8 level LARP as  THE perf
mechanism, next to the printer.  Five of the levels were standard Baudot/Murray coded, and
the other three were 'control' functions for the pull-back TD and dialer mechanism.  These
machines did not need to make tape off the signal line.  All tape preparation took place
from the operator typing on the keyboard.

Ralph - W8ROI


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