Unveiled at SIHH 2016 haute horlogerie exhibition, the URWERK EMC “Time Hunter” is a fully 100% mechanical watch with electronically enhanced indications. It launches in two limited editions of 15 pieces each: one in natural titanium/steel and one with a military green ceramic-coated titanium/steel case.
EMC watch introduced by the brand in 2013. The state of the art EMC Calibre assisted with electronic components enables the wearer to both monitor the health (amplitude) of the watch and its precision as worn on the wrist.
When a watch is regulated (its precision tested and adjusted) by the watchmaker before it is sold, it is usually placed on a continually rotating arm in a fairly temperature-stable room. The rotating arm ensures that the watch spends fairly equal time all positions. But the timing of a mechanical watch changes slightly in each position as well as with changes in temperature. So in the real world of a watch on the wrist, how long it spends in each position (on average) will depend on the wearer's activities: work, leisure, and how long each day it is actually worn. Two different people wearing the same watch for a week will find that its accuracy differs because the watch will have experienced different positions in different activities over the week.
EMC enables the wearer to note how many seconds the watch gains or loses in a week (or month), to adjust the precision, and then test that precision using the EMC function to confirm that the adjustment is correct. This concept of interactivity allows EMC to be as precise as possible for a specific wearer's lifestyle and even to evolve with any changes.
How it works?
The fold-out crank handle is first wound to generate powerfor the EMC indications,– there are no batteries –which is then stored in a super capacitor. After winding, a hand indicates either δ(processing underway) or P (not enough power). The EMC hand will then first indicate the movement's precision to +/- 15 seconds per day for a few seconds, followed by the amplitude of the balance, the latter being a good indicator of the health of a movement and if it requires servicing. As well as these two indications, a LED on the precision display between -5 and -15 seconds will shine either green for “all okay,” or red if one or both of the EMC indications fall outside acceptable parameters.
The precision of the movement can then be simply adjusted faster or slower by turning the screw on the back of the watch. This allows the user to adjust the time to suit their own lifestyle.
What is amplitude and why does EMC measure amplitude?
While the concept of precision (as in how many seconds a day a watch is running fast or slow) is fairly easy to understand, amplitude of the balance is less obvious. The precision of a grandfather clock is regulated by a pendulum swinging back and forth, and the precision of a wristwatch is regulated by a balance wheel with a hairspring inside oscillating back and forth. "Amplitude" is how far in degrees the pendulum or the balance wheel moves through each oscillation.
While in theory both pendulums and balance wheels should be isochronous at all amplitudes, i.e. each oscillation should take exactly the same time whether swinging through a small or large distance, in practice the balance in most wristwatch movements should oscillate with an amplitude between 220° and 280° for maximum efficiency. Because the tiny balance wheel has relatively low mass and oscillates so quickly (back and forth four times each second), the slightest degradation in the lubricating oil of the balance staff (axel) manifests in lower amplitude. So balance amplitude is a good indicator for a movement being "healthy" or needing service. The balance is the very "heart" of nearly every mechanical watch movement. And as with our own heart, the strength of its beat (amplitude) and the regularity of its beat(precision) are good indicators of health.
What's on the back?
Two things to note on the back of EMC before we delve into the nicely finished movement are the timing precision adjustment screw at the top for fine tuning the precision of the movement and the neat pusherat the bottom between the lugs that cleverly pops the crown out. Looking through the display back into the movement we see the cover over the balance housing the optics that measure the precise rate of oscillation of the balance, with a tiny cable leading to the electronics visible through a grill on the right. The vertically stacked double mainspring barrels are also prominently visible beside the electronic circuit board.
The audacious idea of incorporating a Witschi-like measuring instrument in a mechanical watch became a veritable quest for URWERK.
At its heart, EMC has a triple objective: to show how external parameters (positional changes, temperature, and pressure) influence the timing of the movement; to enable the wearer to adjust the timing; and to facilitate interactivity between the timepiece and its owner.
EMC is inherently a precision mechanical watch with an in-house movement conceived, developed, and crafted in the URWERK ateliers in Zurich and calibrated by URWERK in Geneva. The movement meets the most stringent quality control, with its chronometric performance tested in five positions during a 30-day cycle to ensure that it meets the highest standards for a precision watch.
EMC’s movement is equipped with the following features:
- A bespoke balance wheel made of ARCAP, an alloy long admired by URWERK for its non-magnetic and anti-corrosion properties. From the very first glance, the originality of this specially developed balance is striking. Itsperfectly linear morphology is the result of careful calculations to optimize data from the optical sensor, maximize aerodynamic efficiency, and minimize loss of amplitude.
- Power is provided by two large mainspring barrels in series mounted vertically on a single shaft. These provide a long 80-hour power reserve, which is conducive to stable linear timing performance.
- The timing adjustment screw is accessible on the back of the watch and allows the owner to make very fine adjustments to the balance rate regulator by changing the active length of the balance spring by turning a simple screw.
The innovative EMC timing rate monitoring unit has been developed to include the following:
- An optical sensor on the balance wheel capturing the precise rate of oscillation of the 4 hertz / 28,800 vph regulator, over a period of 3 seconds. This sensor consists of a transmitter and a receiver positioned either side of the balance, and is triggered manually by pressing a button on the left side of the case.
- A 16,000,000 hertz electronic oscillator provides EMC’s reference timing rate. The performance of the balance of EMC (4 Hz) is compared against this lightning-fast oscillator to obtain the most accurate measurement possible.
- Artificial intelligence (the computer) determines the difference between the timing rate of the movement and that of the reference oscillator. Each microsecond difference between the two values is expressed as a gain or loss of a second per day of the timing rate. A variation of just 0.0000014 of a second per half-vibration translates as a variation of a second per day.
- Manual-winding generator (the generator). EMC’s monitoring unit (the optical sensor and the computer) is powered by a micro-generator made by the Swiss company Maxon, which is well known for developing motors for NASA’s Mars rovers.
Material: Grade 5 titanium/steel or green ceramic-coated grade 5 titanium/steel
Dimensions: 43mm width, 51mm length, 15.8mm height
Crystal: Sapphire crystal
Water resistance: Pressure tested to 30m / 3ATM
Finishing: Satin finish; bead-blasted
Caliber UR-EMC2 caliber conceived, developed and manufactured by URWERK
Escapement: Swiss lever escapement
Balance wheel: In ARCAP P40, linear balance coupled to the optical sensor
Frequency: 4 Hz /28,800 vph
Balance spring: Flat
Energy source: Vertically mounted double mainspring barrels connected in series
Power reserve: 80 hours
Winding: Manual winding
Finishing: Côtes de Genève, snailing, micro-bead blasting, polished bevels on screw heads
Generator: Maxon® generator with manual winding charging super capacitor
EMC system : Optical sensor controlled by an integrated circuit board ; 16,000,000 Hz reference oscillator
Hours, minutes, seconds; precision delta, amplitude, power reserve.
Timing adjustment screw