Quartz Kitchen Clock Movement

Sidereal Clock

© Brooke Clarke 2007

Quartz Movement

Background

Drive

Marking

Disassemble

In order to use the movement when driven from a more precise time base than the on board crystal this movement was removed from an old kitchen clock.  This was done by prying the clear cover tabs and pushing so the clear cover could be removed.  Then the tabs paper dial and hands were removed.  Finally the movement was pushed out the front after the tabs on the frame were held back.

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.

The small white plastic circle at the 10 o'clock position of the leftmost gear is the armature.










Here the three loose gears have been taken back out to show the metal magnetic path and the armature.  The armature is made from a permanent magnet, but I don't yet understand how it works.

Patents

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 structure
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

3969642 Step motor for electronic timepiece

Sidereal Clock

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.

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