Everybody has seen Telechron clocks and even. US Navy Warren Telechron Clock System. by Robert Simon (CA)

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1 Figure 1. Front view of clock with 8'' dial in heavy, perhaps fully, waterproof Phenolic US Navy specification plastic case. US Navy Warren Telechron Clock System by Robert Simon (CA) Everybody has seen Telechron clocks and even chiming Revere Telechron clocks all using Henry Warren s patented 115/120 volt, 60-cycle alternating current (AC) motor. For many years millions of these clocks required only an AC socket to operate. The clocks operation was similar to a master clock and slave clock system based on Warren s 60-cycle AC motor. Consider the Telechron motor as a slave clock movement it keeps perfect time as long as the power station generator, controlled by a special Telechron master clock, is putting out exact 60-cycle current. The power generating station s high-quality Telechron master clock allowed operators to regulate the generator rotation to keep an average output of 60 cycles. Generators will just slightly slow down with heavy loads applied during the heavy demand of hot days and afternoons and slightly speed up with the much lighter electrical demands during the late night when many workplaces are closed. During these high and low demand times the Telechron master clock helped keep the generators at 60 cycles. 1 This article covers a unique Telechron clock the Telechron Marine clock (Figure 1). I have seen these clocks, on rare occasions, at New England Chapter meetings and once or twice at a National Convention and never paid much attention until I stumbled upon the patent and then understood how interesting and complicated these clocks really are. The clock s mechanism in- 408 September/October 2016 NAWCC Watch & Clock Bulletin

2 Figure 2. US Patent No. 2,026,368 dated December 31, Note exploded view and wiring diagram. The figure was rotated to present the drawings more clearly. COURTESY OF US PATENT OFFICE. cluded three clock motors to operate the clock hands fast forward or fast backward. This mechanism, which could also synchronize multiple clocks, was needed because ships crossed longitudes hour by hour and date lines. Before this design it was not possible to move clock hands forward or backward. Warren invented this design that was patented on December 31, 1935, as US Patent 2,026,368. The design titled Electric Clock And System was described in the first paragraph of the patent as particularly suitable for use on ocean-going ships, such as naval vessels although not limited to such use (Figure 2). The genius behind this clock design is the remote reset of all clocks simultaneously in the circuit and its significant additional functionality. In the 1920s the typical hourly reset or noontime signal synchronizer reset on stationary land-based clocks was fixed to hourly only, and only corrects the actual hour that the clock is showing. The hour on the landbased clock cannot be remotely advanced or retarded to any chosen hour. In later years auto reset systems were developed by Standard Electric Time Co. and other companies, allowing hourly change, say for Daylight Saving Time. This Telechron clock not only can have any hour set for synchronization but it will also set the 60th second on the second hand and then synchronize new times on all the clocks on the ship. A special Telechron design of control switches can set a new exact hour, minute, and second time on all clocks and have time held at any full hour waiting for the start by a radio time signal or a chronometer synchronization. Using control switches ensures that all clocks are coordinated at the same time at any location on the ship to the second. The ship must have an accurate generator supplying the 60-cycle frequency along with 115 volts AC to be the master clock for exact timekeeping or motor speed on the Telechron motors. Also one master set of electric clock control switches are wired between the 60-cycle source and all the clocks. Using the Telechron schematic, I constructed a homemade box with three toggle switches for the master control, mounted to the left side of the clock (Figure 3). The top left toggle turns all motors on and off. The top right toggle will energize the magnet latch that places a hard stop on the hour, minute, and seconds hands. The bottom toggle is rapid hour advance and retard control. As the ship moves east or west, the clocks will have to be adjusted hour by hour. For longitude, the rapid advance or reverse motor would have to be used. 2 The wiring diagram calls this a magnetic latch. A separate block locked from the magnetic latch on the back of the NAWCC Watch & Clock Bulletin September/October

3 Figure 3. View of clock with master toggle switch control panel that controls all slave clocks on the ship. I assume the panel was next to a clock to monitor and confirm the system setting. movement will lock and hold the minute hand at the top of the hour, which would be the 60th minute or the zero minute of the next hour. Holding the minute hand also stops the hour hand at whatever full hour it is on. You must prepare the clocks ahead of time for synchronization, perhaps two minutes ahead of the new synchronizing time to ensure that the seconds hand on all clocks has at least a full minute to make a full rotation and now is at the holding position. You must monitor a clock next to these control switches that is in the line circuit with all the other clocks. At the start signal time you would open the synchronizing hold magnet latch relay switch, and on all the clocks the three hands will start moving and keep a new time. The US Navy contract nameplate shows the clock manufacture date of as compared with the patent date of December 31, 1935 (Figure 4). 3 Let s take a closer look. The heavy Bakelite clock case has almost watertight seals and has easy to read bright gold numbers on a 9'' dial and gold hands against a black background. The clock, dial, and movement have a protective inner case with electrical contact points on the back to marry the fixed contact points in the Bakelite wall-mounted case. 4 The wall-mounted outer Figure 4. Clock nameplate with date of manufacture. case has matching contacts (Figure 7). When the sealed clock unit is secured into the wall-mounted case, the six contacts are made. The wiring diagram (Figure 6) shows the magnetic latch coil, 1 revolution per minute (rpm) 60-cycle motor with coil, and one motor with two separate coils on a long shaft, whereby this rare, high-speed 30 rpm, two-coil motor can run the hands in either direction based on which coil is energized. This motor will rapidly advance the minute and hour hands, forward or backward, doing 1 hour in 18 seconds. On the right side of the clock case is a key that can be inserted through the normally plugged opening at the 2 o clock position for an individual clock, manual 410 September/October 2016 NAWCC Watch & Clock Bulletin

4 Figure 5, top. Entire clock is removed from the wallmounted case as a unit. Shown is the back cover plate with six electric spring contacts, which marry to the wallmounted case. Figure 6, center. Wiring diagram specific to this type and series clock. Figure 7. Inside view of heavy wall-mounted case with contacts. time adjustment (Figures 1 and 7). Removing the inner black dust cover reveals on the movement s back plate, a round 60-minute disk with a notch at the 60th or zero minute, and when energized the magnet latch will drop a block into the notch to hold the top of the hour time fixed (Figure 8). At the same time this same magnet latch will lower a hard stop metal strip to block the movement of the second hand at the 60th or zero second, and a small slip and friction washer on the seconds hand shaft allows the 1 rpm motor to keep moving while the hand is waiting for the exact sync time when the block will be removed (Figure 9). Figure 10 shows a view looking down on the mechanism from the top of the clock. Figure 11 shows the 30 rpm motor with a long shaft to allow for two separate coils that make it operate in either direction for rapid hourly advance or retard as a function of which coil is energized. Figure 12 shows the motor and two coils out of the movement. There is a normal 1 rpm motor for the seconds dial and the same motor is also geared into the minute hand and hour hand (Figure 13). To understand the internal operation of the Telechron motor, you can see a sealed motor and a motor with its outer case removed and re-mounted in the AC coil in Figures 14 and 15. The AC coil is wrapped around layered iron plates that will be magnetized at each cycle of the 60- cycle per second frequency. The Telechron fixed magnet has two copper metal straps on opposite ends of the iron plates, and these straps affect the magnetic field to force rotation in one direction only. There is a 1 rpm motor that runs the hands as a normal clock through a set of differential gearing, and the 30 rpm motor also through the same differential gears for rapid advance and retard. Concurrent with the 1 rpm motor, the clock uses the differential gearing with the 30 rpm motor in either direction to reset clocks at any top of the hour. 5 Figure 16 shows the differential gearing allowing safe concurrent motor operation. Note the beveled gear (upper right) and shaft going to the top of Figure 16. This top shaft goes to an opening in the case where a key can manually adjust that specific clock. Figure 17 shows the magnet latch arm with its pin that projects out the back of the movement to hold the minute hand on the top of the hour simultaneously moving a metal lever that drops NAWCC Watch & Clock Bulletin September/October

5 Figure 8. View of hour rotating wheel with notch at the 60th or zero minute, and when energized, the magnet latch will drop a block into the notch to hold the top of the hour time fixed until released for the synchronization event. Figure 10. View looking down on the mechanism from the top of the clock, magnet latch on left above the 1 rpm motor and 30 rpm motor at the very bottom on right. Figure 11. View of 30 rpm motor with a long shaft to allow for two separate direction coils that make it operate in either direction for rapid hourly advance or retard. Figure 9. Close-up of seconds dial and drop magnet latch block to hold seconds hand until synchronization. Note slip clutch on the seconds hand shaft that allows the 1 rpm motor to run while hand is held. the stop arm to block the seconds bit at the 60th second for time synchronization. Early twentieth-century Marine master clocks allowed exact minute advance and retard control of the ship clocks, 6 but they did not have seconds hands. These Telechron clocks can be challenging to work on, and in my case, the motors had to be professionally overhauled. You do need to design and build a simple set of control switches. These clocks are rare and unusual. 412 September/October 2016 NAWCC Watch & Clock Bulletin

6 Figure 12. View of rapid advance motor and coils removed from movement. Figure 13. View of typical 1 rpm motor. About the Author Robert A. Simon retired after 40 years of a diversified career in all aspects of railroad civil engineering. He and his wife have been clock collectors since 1976, and they now live in the San Francisco Bay area. Their horological interests are diversified under the electromechanical and commercial and industrial timepieces genre. Simon has written for the NAWCC Bulletin on Marine master clocks and railroad operations clocks. Figure 14. Motor in case housing, left. Motor movement, right, as it would fit in electromagnets that go through AC coil. Note two copper bars pressed on the magnets, which induce a slight change to the magnetic field to force the motor to run in one direction. Figure 15. Side view of motor movement in electromagnet. Notes 1. For additional information, the author recommends Robert Simon, The Marine Master Clock, NAWCC Bulletin, No. 373 (April 2008): The bottom toggle switch moves the minute and hour hands in either direction, rapidly, at about 18 seconds per one full hour. 3. I have tried to obtain information from the US Navy archives in Washington, DC, and none could be found. 4. See the six electrical spring contact fingers on the clock above the wiring diagram in Figure As noted earlier, the 30 rpm motor gearing sets the minute hand and therefore the hour hand as well. 6. This was in the traditional sense of putting out electrical minute impulses to the ship s slave clocks. References Anderson, John M. Henry Warren and His Master Clocks. NAWCC Bulletin, No. 273 (August 1991): Electric clock and system: US A. Google Patents. Accessed August 19, com/patents/us ?dq=us+patent &hl= en&sa=x&ved=0cb0q6aewagovchmittrtmqw2xwi VQzU-Ch1lSgIr. NAWCC Watch & Clock Bulletin September/October

7 Figure 16. View shows the differential gearing that allows safe concurrent motor operation on left. Note the beveled gear (upper right) and shaft going to the top of case. This top shaft goes to an opening in the case where a key can manually adjust that specific clock. Figure 17. Close-up of magnet latch in nonenergized position. The seconds and minute hand stop blocks are clear for normal timekeeping. Closing the circuit with the toggle switch moves this lever and blocks the clock for synchronization. 414 September/October 2016 NAWCC Watch & Clock Bulletin