The final rotor in the Telechron lineup was the S series. This was the smallest
Telechron rotor consisting of a lower cost aluminum case. The S series clock motor
replaced the H motors during the 1960's to 1970's. The most common S series rotors
have a 10 tooth pinion gear but some have a 15 tooth gear for specialized applications.
These rotors were also used in oven and stove clocks/timers and clock radios.
The O.D. of an S rotor is about 1-1/16".
Below is the standard Telechron S-1 type rotor and the complete motor assembly with
This is the S series rotor with 15 tooth gear. It's usually marked S-4.