Definitions

electric clocks

Electric clock

An electric clock is a clock that is powered by electricity instead of powered manually or by other sources of energy, specifically in order to wind the mainspring or to drive the pendulum or oscillator.

Classification

There are actually four basic design classifications:

  • Electromechanical clocks that use mechanics to rewind the mainspring (via attachment of a motor or an electromagnet)
  • Electromechanical clocks that use mechanics to operate the pendulum or oscillator
  • Electromagnetic clocks that use electromagnetic impulses to operate the pendulum or oscillator
  • Synchronous clocks that use the 50 or 60 Hz oscillation of the AC power line as a timing source, by driving the clock gears with a synchronous motor.

History

In 1814, Sir Francis Ronalds (1788) of London invented the forerunner of an electric clock, the electrostatic clock. His prototype was powered with a dry pile battery. It proved unreliable in timekeeping, however, because of a strong dependence on a stable room temperature and 'weather conditions'.

In 1815, Giuseppe Zamboni (1776-1846) of Verona invented and showed another electrostatic clock run with dry pile battery and an oscillating orb. Over the test of time Zamboni's clock was praised "the most elegant and at the same time the most simple movement yet produced by the electric column". Zambodi's clock had a vertical needle supported by a pivot and was so energy efficient that it could operate on one battery for over 50 years.

Numerous people were intent on inventing the electric clock with electromechanical and electromagnetic designs around the year 1840, such as Wheatstone, Steinheil, Hipp, Breguet, and Garnier, both in Europe and America.

In 1840, Alexander Bain (1811-1877), a Scottish clock and instrument maker is the first to invent and patent the electric clock. His original electric clock patent is dated October 10, 1840. On January 11, 1841, Alexander Bain along with John Barwise, a chronometer maker, took out another important patent describing a clock in which an electromagnetic pendulum and an electric current is employed to keep the clock going instead of springs or weights. Later patents expanded on his original ideas.

Matthias Hipp (1815-1893), clockmaker born in Germany, is credited with establishing the production series, mass marketable electric clock. Hipp opened a workshop in Reutlingen, Switzerland, where he developed an electric clock to have the Hipp-Toggle, presented in Berlin at an exhibition in 1843. The Hipp-Toggle is a device attached to a pendulum or balance wheel that electromechanically allows occasional impulse or drive to the pendulum or wheel as its amplitude of swing drops below a certain level, and is so efficient that it was subsequently used in electric clocks for over a hundred years. Hipp also invented a small motor and built the chronoscope and the registering chronograph for time measurement.

The first electric clocks had prominent pendulums because this was a familiar shape and design. Smaller clocks and watches with a spiral-balance are made on the same principles as pendulum clocks.

Electromechanical Clock

Description

The configuration of this device is comparatively very simple and reliable. The typical deviation of the electromechanical clock is about 10 seconds per hour and it usually can run for about a year using the energy of the single battery. The electrical current powers either a pendulum or an electromechanical oscillator. The electromechanical oscillator component has an attached magnet that passes two inductors. When the magnet passes the first inductor or sensor, the simple amplifier opens the current across the second inductor, and the second inductor works as electromagnet, providing an energy pulse to the moving oscillator. This oscillator is responsible for the accuracy of the clock. The electronic part would not generate electrical pulses if the oscillator is absent or does not move. The resonance frequency of the mechanical oscillator should be about several times per second.

In the presented diagram of the 1968 year electromechanical clock, the resistor R1 can be about 27 kΩ, the capacitor C1 about 25 μF and capacitor C2 about 0,033 μF. Both inductors have about 2300 windings. The device is a common collector amplifier, opening current across the inductor Lu only when the oscillator magnet passes the sensor inductor L0, causing the base current and opening the transistor. This clock uses the 1.5 V battery (the most of devices used 1.5 - 4.5 V power source).

See also

Notes

References

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