Junghans Electromon Master Clock
Circa 1929
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I think this is one of the most fascinating clocks in my collection. This Junghans clock that
is wound by a "Heat Pump". A tag on the back of the clock reads "Luftpumpe Night Olen!" which
means "Don't oil the air pump". The air pump is a heating element inside a sealed canister.
The dial has been removed so you can watch the mechanism wind once every minute. Because it winds once a minute, power to
the spring that drives the escape wheel stays consistant so the clock can be very accurate. In 1929 the 60 cycle standard had
not yet been addoped by the power companies so an electric clock was out of the question. If you made an electric clock at that
time, the clock would run either fast or slow depending on the power company providing your power.
What they could do before the 60 cycle standard was addopted about 1932, was to build mechanical clocks that were wound by electric power.
The problem with mechanical clocks being wound by electrical power was that they either used a vibrator solenoid to wind the clock or
a large electric motor. The vibrators made a lot of noise, and the motors were too large to be practical for domestic use. The Junghans Electronom
was the answer. Once a minute a contact would close and for one second 120 volts would go to a heating element that was sealed inside a small canister.
During this one second, the electric heating element would cause the air inside the canister to expand.
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This expanded air would travel through a small
rubber tube to a small cyclinder and would push a piston up. This piston was connected to a ratched that would wind the clock.
Electricity heating air does not make any noise so it became the first practical electric clock for home use.
The heated compressed air could also be delivered to slave clocks that were designed to advance by air pressure. Because of the design,
this Electronom was not only a great clock for home use, it was a master clock that could advance other slave clocks without making any noise.
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