Telechron wood case electric wall clock ca. 1926


Telechron History at clockHistory.com

Telechron Telalarm Jr. electric alarm clock ca. 1947


Telechron Type F and Type H Electric Clock Motors

Wanted: Old F and H rotors - working or not! Paying up to $1.00 each for H rotors such as the nickel plated or copper ones shown below (or brass ones). The housing must be undamaged and have no holes drilled in it. I'll accept the the newer aluminum rotors as a donation, but will not pay for them. if you can help.

Clocks using the Telechron type F motor were introduced in 1932. The field coil unit is similar to that for the type B. The rotor unit is smaller than a type B rotor because one reduction gear was eliminated, increasing the output speed from 1 revolution per minute to 3.6 revolutions per minute. Type F rotors have a two piece housing, with the main body being a die cast piece. Type F rotors for alarm clocks have a long shaft on the output pinion, and those for time only clocks have a short shaft (thanks to Jay Kennan for clarifying this).

Clocks using the type H motor were introduced in 1937. The type H also has an output speed of 3.6 revolutions per minute. As far as I can tell, the difference between the type F and type H rotor is the housing. Some early H rotors have a long shaft output pinion, but most have the short shaft. The H motor became standard for domestic clocks, and was used for many years. It recently became obsolete.

The pictures below show a type F rotor, some early H rotors, and some standard H rotors.

Bottom view of type F rotor
Side view of type f rotor showing long shaft output pinion
Above and below: Type F1 rotor, long shaft version. Die cast housing with integral spacer for mounting the field coil unit. The reddish-brown substance on the top of the rotor (below, right) was used to seal the housing where the two portions are joined.
Side view of type F rotir
Top view of type F rotor, showing where the two parts of the housing join

 

Below: Early Type H Rotor with long shaft output pinion
Bottom view showing mounting feet used only on early examples of type H.
Bottom of early type H rotor showing mounting feet

Side view showing long shaft output pinion.

 

Side view of early type H rotor showing long shaft output pinion

Rotor is labeled:

H3
TOP
M1321
3.6 RPM
60 CYC.
095

The other side of the rotor is labeled:

Telechron, Inc.

Top view of early type H rotor

 

Below: Early H Type Rotor with Mounting Feet
Bottom view showing mounting feet and brass bottom plate.
Botton view of early type H rotor with standard short shaft output pinion and mounting ears
Side view showing standard length output pinion.
Side view of early H rotir with short shaft output pinion

Rotor is labeled:

H-3
TOP
M1313
3.6 RPM
60-C
88

The other side of the rotor is unlabeled.

Top view of early type H rotor

 

Standard H type rotor in nickel plated housing. Rotor is labeled:

H3HP
TOP
M1630
3.6 RPM
60-C
87

The other side of the rotor is labeled:

Telechron Inc.
Ashland, Mass.

Bottom of standard type H rotor in silver color case
Top of standard type H rotor in silver color case
Side of standard type H rotor in silver color case

 

Standard H type rotor in copper housing. Rotor is labeled:

H3 HNK
TOP
M2275
3.6 RPM
60C
335

The other side of the rotor is labeled:

Telechron

Bottom of standard type H rotor in copper case
Top of standard type H rotor in copper case
Side of standard type H rotor in copper case

Notes:

The meaning of the designations after the motor type (such as the H3 HNK or H3-HP) are unknown to me. Likewise with the “M” number and the number under that. They may be date or batch codes.

The most recently made H rotors (from the 1970's and on) have aluminum housings.

I have two other early H rotors with mounting feet. They are labeled:

H-3
TOP
M1313
3.6 RPM
60-C
99_
 
60-3
6
710
H3
 
M1313
There is no company name on either rotor

Notes on type F:

I have two type F rotors with standard length output pinion. They are both labeled as follows:

60-3
6
512
F1
 
M519

 

The letter in a clock’s model number indicates the type of motor it was originally designed for. For example, a 7H98 uses an H motor. Some clocks with F in the model number contain an H motor. A 7F59 contained the F1 rotor shown at the top of this page. Models 2F02, F327, 7F71 and 8F03 that I examined had a standard silver color H rotor. An alarm clock made for a type F motor would have been designed for the long shaft pinion. But starting in 1937 the same model would have been made to take the short shaft type H motor.

Time only clocks made for a type F motor can have a regular type H motor put in. But alarm clocks made for a type F rotor were made for the long shaft output pinion, and needed the special long shaft H rotor when the original F rotor went bad.

Thanks to Jay Kennan for clarifying the dates of the F and H motors, and for explaining that the long shaft F rotors were for alarm clocks. Visit his Pappy’s Telechron Clock Page for more history, and beautiful photos of hundreds of Telechron clocks.

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