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How Auto Set Movements Saves Time in Our Everyday Lives


Auto set movements have changed the way we adjust clocks for Daylight Saving Time (DST). For the past decade or so radio controlled movements were the best way to do this. The clock movement would receive a radio signal, and either stop or fast forward an hour when needed. In theory this was a great idea because the time broadcast is based on the Caesium -131 Atomic Clocks in Fort Collins, Colorado.

The accuracy is the result of the process of radioactive decay. The term decay in this case means “change.”  A radioactive substance naturally changes by emitting particles (protons, neutrons, or electrons) which results in the production of a different element. For example, uranium decays into lead.  Caesium decays into barium.

The detection of these particle emissions by a sensor (as in an atomic clock) generates the time signal.  The accuracy of this natural process is not affected by temperature, pressure or any other environmental factors. An atomic clock will work just as well in space as anywhere else.  Atomic clocks are accurate to better than one second over 200 million years.

Unfortunately, there are a variety of AM broadcast vulnerabilities which undermine the reception of the atomic clock signal.  Although AM (amplitude modulation) radio can achieve great distances, these vulnerabilities include interference from appliances, power tools, light dimmer switches and (especially) solar geomagnetic storms which are quite common.  At their strongest, they cause the atmosphere to “light up” in northern and southern regions of earth, producing the northern (and southern) lights.

Fort Collins, Colorado is a significant distance from many areas in the US, rendering locations in Maine and Florida susceptible to signal interruption. Further issues are the result of clock placement in basements or thick walled buildings with few windows. The thin metallic composition of some modern window coatings is sometimes cited is a factor in AM reception degradation.

Anyone who listens to AM radio while driving under an underpass will hear the momentary drop in signal strength. FM (frequency modulation) signals with their higher frequencies are barely affected, but FM does not have the ability to travel great distances as AM does.  Hence, the so called “short wave” radio is an AM band.

These clocks remain popular, but we at Clock Parts have introduced Auto Set movements which take advantage of a new technology which utilizes a digitally based chip which serves as a pre programmed movement. The main power source is the AA battery, but the time is sequenced by a miniscule quartz chip which oscillates at a very regular frequency and requires extremely low voltage. The common, and long lasting LR44 battery keeps the chip running when the standard AA battery is removed and replaced.

The AA battery also drives our high torque movements capable of operating clock hands nearly 18″ long. A common use is for large wall clocks that may be installed high up on a wall. Imagine not having to get out a ladder to change the time twice a year! In the Fall, the internal clock movement will signal the movement to stop operating for exactly one hour (fall back). In the Spring it will make the movement operate at a high speed for about 6 minutes to advance the time by one hour (Spring forward). You don’t have to do a thing, just sit back and watch if you are still up at 2:00 am.

We have Auto-Set movements for operation in the four time zones of the continental United States (MVT708USAS) as well as a “world” model (MVT708GSF) that can operate in all 26 time zones around the world. Pretty much amazing. Both of these movements have a 5/16″ threaded hand shaft length, which will work with a clock face or clock dial thickness up to ¼”.

They also use the common American “I” shaft configuration, which makes over 50 hand styles and lengths available for these movements. Use these movements to repair an existing wall clock or make your own design. You can even use one of our wall mounting cups to mount the US version to the wall, so you can use photos or stick-on numbers to tell the time. Get your creative juices flowing!