Quartz Kitchen Clock Movement
Sidereal Clock
© Brooke Clarke 2007
Background
Drive
Marking
Disassemble
A number of plastic hooks hold the mechanism
into the movement box. All but one of these can be seen and
with a small screwdriver pried enough to lift the mechanism up a
little. But the one under the printed circuit board seemed
impossible to get to, so I cut a hole in the box. Here a
bottom view. Note that three gears and a flat spring dropped
off and have been reassembled for this photo.
Patents
788762 Electromagnetic device, Albert Favarger, May 2, 1905, 310/163 - bipolar DC drive rotates clock hand
1405502 Electric motor, Dodds Lee L, Feb 7, 1922, 310/49.47 - intended for slave clocks, but is a bipolar DC drive using 4 coils.
1603646 Electrical transmission system, Jr Elmer A Sperry, Sperry Gyroscope Co Ltd, Oct 19, 1926, 318/695, 188/171, 377/89, 310/93, 340/319, 310/127, 310/406, 310/216.92 - up to 20 steps per revolution, works after power failure
2036917 Electric timepiece, Philippe Favre-Bulle Maurice, Apr 7, 1936, 368/47, 968/482, 310/21, 310/25 - a vibrating reed (half a tuning fork) drives gear wheel
2499316 Magnetic motor for visual indicator units, Johnson Ernest W, Transducer Corp, Feb 28, 1950, 377/82, 318/696, 340/317, 377/89, 235/61.0PK, 310/49.31 - includes a spring to return to starting position
2659853 Electric impulse motor device, Montford Morrison, Nov 17, 1953, 318/491, 318/443, 318/499, 968/550, 318/558, 310/49.22 - single direction stepping
2457637 ELECTRICAL MOTOR, Harrison D. Brailsford, Dec 28 1948, 310/46 ; 310/40MM; 310/40R - self starting (offset magnetics) pulsing clock drive motor, very low power
Fig 4 shows the structure3969642 Step motor for electronic timepiece
References:
362322 ELECTRIC MOTOR, EOBEET J. SHBBHY, May 3, 1887, 310/46 - 4 coil looks like start stop stock ticker drive
1367982 MOTOR, QTTSTAVE Lidseen, Feb 8, 1921, - AC/DC armature has teeth instead of windings
2185990 INDUCTION MOTOR, self starting
2214850 SELF-STARTING SYNCHRONOUS MOTOR, GE 1939 - uses permanent magnet for rotor
References:
1497394 Alternating Current Motor, Henry E. Warren (Warren Clock Co), Jun 10 1924, 310/163 ; 310/126 - self starting AC synchronous
In 2014 there was some interest in "Crazy Clocks" where the time would stop and then run fast. To make these a small printed circuit board was put on the market with a number of different versions of the Crazy Clock and one of those versions was for a clock that tells sidereal time (Wiki).
To be useful a sidereal clock needs to tell Local Sidereal Time (LST) not some universal sidereal time, i.e. to take into account your longitude offset from the center of your time zone. That way if you know the Right Ascension (Wiki) of a star that's the sidereal time when the star crosses your local North - South meridian.
To make this clock I started with a "10" Zulu Time 24 Hour Wall Clock" from eBay seller pilotmallaviationsuperstore and a "Crazy Clock" PCB with the Sidereal option.
Fig 1 Remove the clear plastic clock bezel by pressing the 3
fingers on the back in and out using a screw driver and remove.
Note the hands are all at midnight.
Pull off the second hand.
Remove the nut and minute hand.
Pull off the hour hand.
Remove the nut and washer and remove the Quartex 24h movement.
The instructions on how to open the Quartex are on the Crazy Clock web page.
Cut the two battery traces and the two motor traces as
shown below and solder wires as shown below.
Cut notches in the plastic cover to clear the wires.
Place "SIDEREAL" label over Zulu Time.
Solder red wire to Batt+ and black wire to Batt-.
I don't think it matters which motor wire goes to which terminal.
Fig 2 Crazy Clock board installed in clock.
Fig 3
To set the clock you can use the USNO LST web page: Compute Local Apparent Sidereal Time
PS. Since the clock comes with all three hands pointing to midnight, it makes is much easier to start up the clock at midnight LST or shortly thereafter. That way you do not need to rotate the time setting dial a million turns.
