[GreenKeys] 35-KSR - 50Hz gears

[gfmurphy at earthlink.net]

Teletype did make 50Hz gears for the Model 35 KSR.  The gear set was 
numbered 307852.  It consisted of a 307846 pinion with 20 teeth and a
307847 gear with 70 teeth.  The ratio of the two gears is .285714.  
This is the same gear set that would be used if you wanted to run a
Model 28 page printer at 100 WPM with a 50Hz, 3000 RPM motor.

The standard motor for a  M28 or M35 KSR or RO was the LMU3.  If you
wanted to run those machines on 50Hz current (3000 RPM), an LMU38 
motor was used.  There is one small difference between an LMU3 and 
an LMU38:  They have different thermostatic switches. If you wanted
to use an LMU3 (60Hz, 3600 RPM) on 50HZ current, all you had to do
was replace the thermostatic switch.  An easy work-around would be to
bypass the thermostatic switch and insert a suitably sized slow-blow 
fuse in one of the motor leads.  Other than the thermostatic switch, 
there is no difference between the LMU3 and the LMU38.

Model 35 ASR sets used 1/20th HP motors:  LMU3 on 60HZ current and
the LMU38 on 50HZ current.  (Model 28 ASR sets used the 1/12th HP
motor:  LMU12 on 60HZ and the LMU50 on 50HZ.) 

The LMU50 is the 50Hz, 1/12th HP motor for use on 28 ASR sets and 
multiple mounted reperfs.  It is the same diameter as the LMU12 but 
it is about an inch and a half longer than the LMU12.  The motor 
starting relay is also mounted externally on the LMU50.

One possibility you might consider is to use a governed motor in place
of the synchronous motor.  The governed motor would turn at 3600 RPM
and 'normal' 100 WPM gears could be used.  A suitable step-down
transformer would be needed if the utility voltage is not 120 volts.

Jerry Murphy