Telechron, Inc., Ashland, Massachusetts, USA. Model Type
C, 1926, serial no. 7. Page 4.
Restoration. General cleaning and repairs, movement
After all of the missing parts were fabricated they were installed into the movement
and the clock was tested for functionality. Once this was confirmed the entire movement
was disassembled for a typical cleaning. The movement had 256 parts.
First the movement is disassembled. Other than the missing parts it was in very good
'as found' condition.
Non-flammable, degreaser and ammonia-free brass cleaner was used to get the parts into
a clean condition. Afterward Simicrome metal polish brought about a high finish. The parts
were then again put into the ultrasonic cleaner to remove all traces of the polish. The
two main plates originally had a vertical grain finish which was retained.
The first photo above shows the friction clutch mechanism that is used to advance or
retard the chain, thus advancing or retarding the slave clocks. Reassembly was a bit
tricky given the entangling chain drive as well as the clutch mechanism on the top plate.
The completed movement. I allowed the plates to be exposed to the air for two weeks to
allow just a bit of a mellowing color that I like on brass. The plates were then treated
with Renaissance crystalline wax to prevent further tarnishing. Notice the fact that I use
a gloves. From this point on I will not touch the plates. This type of protective coating
is quite fragile and I chose it because the movement is protected within a wood and glass
case with no possibility of anyone touching the metal. This is my first use of this
material and I'm interested to see how well it performs over the years.
Next the knife switches are cleaned and restored. The knobs were missing, but
fortunately stock knobs that looked very much like those on the extant wooden case
connection block were available.
Wherever screws where originally blued, but corroded, I first cleaned, finished and
polished the screw. Then using a heat gun re-blued the screw to the appropriate color.
This screw was used to secure the knife switch to the wood case.
Next. I replaced the white zip cord wire that was attached to the existing motor coil
and was itself a sloppy repair. I used NOS wire that replicated the type of cloth wire
that would have been used at the time and insulated the solder junction with shrink tube
for a neat fit. The case tag in the last photo of the prior row shows the serial number of
seven and the voltage being 110 and the cycles 25. This matches the cycles on the motor
tag of the one motor that was with the clock when received (shown). Also both tags are of
a similar design, brass material with black foreground; both stating the manufacturer as
Warren Clock Co., General Electric, Co., USA. This important because the motor tag has the
most recent patent date as May 27, 1924. A small sticker on the rear case door which looks
old, and otherwise might be subject to doubt, but with the corroboration of the motor tag
seems to be correct in that this unit was first put into service on August 11, 1926.
This brings into focus an interesting conclusion. The Type C was first introduced in
1920. Yet we have a unit of serial #7 being put into service in 1926. The Telechron
company used a sequential serial numbering system on their master clocks. The motor tag
would preclude anything earlier than 1924. Given the unusual frequency of 25 cycles and
that they match up between the motor tag and the case tag it's safe to say the motor is
original. This would seem to indicate that only seven of the Type C were produced from the
introduction in 1920 through 1926, about one per year. This is in sharp contrast to the
company's highly successful Type A which by this time had a production of somewhere around
400 and would explain the fact that there is only one example of the Type C, while dozens
of the the Type A are known.
The completed movement, less the tilt-table and movement contact block. The rear view
shows the motor before re-wiring.
The clock was wired up using NOS type cloth wire, with the exception of the coiled wire
that attached the mercury switches to the tilt table. The photos from the NAWCC article
showed very thin, probably 35 AWG, solid core coils. I tried this type of wire, magnet
wire with clear insulation and it did not look right, and it was still rather stiff. So I
used a 24 AWG, braided, insulated wire and this had the right look and flexibility that I
thought was appropriate.
Unlike all other master clocks from the Telechron company this clock could not be wired
up as originally from the factory and be expected to work normally. The clock was designed
to run in a DC current environment and so needed rotary converters to operate properly.
These converters were never a part of the clock itself, but were provided, along with a
large control panel as additional units to be connected to the clock. These converters can
be seen on page six describing the theory and
functionality of the clock. They look to be quite large, certainly too large to fit within
the case of the clock itself. Without these components the clock cannot function as
designed. So I wired the synchronous motors to the tilt table. For this plan to work,
however, the motor must run just a bit too fast, in other words run at a rate in excess of
60 cycles. This way the fast motor will cause the weight to rise faster than the clock
unwinds the chain, thus raising the table and causing the circuit to open, stopping the
motor. Now the clock can 'catch up' allowing the weight to fall and the table to tilt
back, closing the switch and re-energizing the motor beginning the cycle again. Thus the
weight is continuously raised to keep the clock running. If the motor run too slowly the
clock will run down and if it run exactly as the master clock it will still not
work because if the exact rate is achieved when the switch is open the clock will run
down. If it is running when the switch is energized it will work but only as long
as it is exactly in synch with the master clock. Suppose that the frequency today is
controlled by atomic clocks, this will exceed the performance of the master clock and so
they will not be exactly in synch. At some point an error will occur between the two rates
and the clock will eventually stop.
The fail-safe way is to have a slightly fast motor. To do this I obtained a European 50
cycle synchronous motor made by Telechron, which, by the way is of the same dimensions as
their US 60 cycle counterpart. So I simply slipped the 50 cycle rotor into a US coil and viola!
You now have a rotor that would rotate at once per minute at 50 cycles per second now
being driven at 60 cycles so the output is now 20% faster. It works perfectly for