Telechron Clock Rotor Type B
The Telechron B rotor was used in the earliest Telechron/GE clocks. Later versions
were developed to power the higher torque applications found in striking and chiming
clocks.
The O.D. of B series rotors is a little over 1-1/4".
The Telechron B-2 rotor was one of the earliest B style rotors. It started out in
a copper case and was later switched to brass and nickle/brass. The most common
output shaft configurations were 1/8" X 1/2" solid and 1/8" X 1/2" hollow with a
9 small tooth gear on the end. The hollow shaft shaft was used to accept the clock's
second hand.
The Telechron BF series rotors had shorter tails which fit the same coils as H rotors.
Typical configurations were 18 and 36 tooth drive gears. The 36 tooth version was
made with a 9/16”, 3/4” and 13/16” O.D. Pinion gear.
36 tooth (9/16” O.D.):
The Telechron B-3 rotor was primarily used in striking and chiming clocks. (At 4
watts it was double the torque of the B-2). The most common configuration was 1/8"
X 1/2" solid shaft. (sometime a flat spot for a set screw). B-3's rotors are almost
always in need of gear and bushing replacement due to the demanding torque.
The Telechron B-13 rotor was Telechron's last B style rotor and continued into the
1970's. Like the B-3, it was also a high torque design. B-13 rotors had a serious
problem. GE took over production from Telechron and decided to switch from oil to
grease and this defeated the whole purpose of the Telechron capillary lubrication
system. In addition the grease quickly dried up which left the rotor starved for
lubrication. My theory is that they used grease because they went to a cheaper crimped
aluminum case and oil could seep from the crimp. When I restore a B-13 it get's
converted to synthetic oil and the crimp is sealed with special epoxy so there is
no oil seepage.
Other variations of the B rotors included the Telechron BC series that runs at 60
RPM. The B-8 had an oil drain plug** in the tail and there's the Telechron BCN 12
watt "torque monster". (** I don't believe the B-8 plug was intended for oil changes.
If anyone know it's real purpose I'd love to know.)
The below image is a very scarce B-16 rotor. The B-16 has a short tail like the
BF series and is used with thinner H-3 style coil assemblies. It appears that the
main difference between BF and B-16 rotors is that BFs had pinion gears yet the B-16
has a standard 1/8" X 1/2" shaft.
Telechron’s largest rotor was the C5 which was primarily used in tower clocks. Here’s
some images of these compared to std. B’s.
36 tooth (13/16” O.D.). This was the largest drive gear of any Telechron rotor.
(Used on BF6 series)
Telechron B-2 rotors were also used in the cyclometer series with the rotating number
wheels. For these clocks the rotor had a small threaded shaft for attaching a cam.
The vertical cyclometers had a L.H. Thread (see image). The horizontal cyclometers
used a R.H. Thread. It’s common to see this little shaft and the cam threads stripped
from improper removal .
