Introducing the Accutron Electrostatic Concept Movement
Wednesday - 09 December 2020
Not all horological innovations need to come from Switzerland. Seiko, founded in Tokyo, has been refining the art of precision instruments since 1881 and pioneered the first quartz wristwatch. But let’s rewind to a time even before this. In 1952 the dynamics of precision timekeeping changed when Bulova realised that for it to stay ahead of the game, it would need to look further into a new technology brought to the table by watchmakers, Elgin and Lip. It was the concept of an electrical watch. After carrying out some deeper research, Bulova predicted that these new battery-driven watches would never give the wearer complete, unparalleled precision whilst still being powered by a balance wheel. The secret to the success would instead be the newly developed transistor, which before then, had only ever been used in the music industry.
The history of the Accutron Tuning Fork technology
Bulova’s Accutron watch was defined by the use of a tuning fork which divided each second into three hundred and sixty equal parts. The ‘Accutron Project’ was governed by Max Hetzel, a Swiss engineer recruited by Bulova in Bienne in 1950. The first official Bulova Accutron watch with the tuning fork concept was released in 1960 adopting the name ‘Spaceview’ since it had no proper dial and instead featured an open-worked display that exposed the workings of the tuning fork sitting inside. Two of the signature features of the Accutron were its accuracy to run within a minute or less per month and the high-pitched humming sound it emitted whilst its sweeping seconds hand graced the surface of the display. The Accutron tuning fork made a remarkable impact on the watch industry, the concept of which still makes for a popular talking point amongst watch connoisseurs today.
Amongst Bulova’s many ground-breaking achievements, its Accutron watches were used as a cockpit instrument, in aviation experiments and also assisted NASA’s Apollo missions. Furthermore, they were used before this in space as a timekeeping instrument, integrated into communication satellites. Accutron watches were forced into a quiet period during the 1970s as a result of the quartz crisis and its devastating effects on many prestigious independent watch companies during this time. Gradually it ceased production altogether.
The new Accutron Electrostatic movement concept
Citizen and Bulova now mark a new generation of movement with the unveiling of an electrostatic movement which launched officially in 2019 at Baselworld. Interestingly, it borrows some features from the Accutron tuning fork technology but also generates power in a new way. Powering the Spaceview 2020 watch and the Accutron Spaceview DNA watch, which we covered here (link), the dial exposes the movement but goes without the tuning fork. Instead, if you look towards the bottom half of the dial, two turbine-like structures can be seen. These are balanced by a larger turbine (the electrostatic motor) seen at the top of the dial and rotate rapidly when the watch is in motion.
Now, here’s where things get a little more technical. The motor sits within two electrodes and uses the direct repulsion and attraction of negative and positive electrical charge. Just as identical charges repel one another, when the rotor passes an electrode with an identical charge it pushes the rotor away and causes it to turn. One advantage of the electrostatic motor compared to an electromagnetic motor (which operates slightly differently), is that the electrostatic motor requires no coil wound rotor, resulting in a more compact construction, but also one that uses less energy.
Accutron’s proprietary electrostatic movement is powered by the same arm movements you see in an automatic watch. The system drives the second hand around the dial in a sweeping-like motion, echoing the behaviour and character of the original Accutron tuning fork mechanism. The hour and minute hands are propelled by a stepping motor – both systems of which are controlled by quartz timing.
Aside from its complex construction, the Accutron electrostatic motor is quite a spectacle to see in the flesh. It provides visuals unlike any other watch on the market and differs from other innovations like the Seiko Spring Drive (since this mechanism is powered by an electromagnetic rotor and relies on a mainspring). Incorporated into the Accutron Spaceview DNA watch, which you can learn more about here, Accutron’s electrostatic timekeeping technology also offers an innovative power-saving feature where the second hand ceases at 12 o’clock after five minutes of non-activity. At the same time, the hour and minute hands continue to power on, keeping accurate time. To resume the motion of the seconds hand, the wearer simply swings his arm up and down for a few seconds and the power reserve motion is cancelled.
Accutron’s electrostatic motor technology is also integrated into the Accutron Spaceview 2020 watch which you can check out here on the Jura Watches website. Shop all the latest Accutron watch releases and more by getting in touch with the team on 01335 453453 or send us a message at help@jurawatches.co.uk.
