Throughout the ages, watchmakers have striven to perfect the power supplies which provide the energy to power the mechanisms. The process started with the mechanical watch, which uses the main spring to energize the mechanisms, followed by the automatic watch, quartz watch, kinetic watch, and finally, the solar watch.
The difference between automatic and kinetic watches is in how the energy is stored within the watch. Automatic watches store the energy in the mainspring, which slowly unwinds and moves the mechanism, whereas kinetic watches store the energy in a battery that powers the quartz mechanism.
Automatic watches store the energy in the main watch spring, which powers the mechanical mechanism. Kinetic watches have minute generators that power the wearer’s arm’s movement and store the resultant current in the batteries.
How Do Automatic Watches Work?
Automatic watches are sometimes called self-winding watches.
These watches have a mechanical movement (the watch’s mechanism) where, instead of the mainspring being wound manually by turning the crown, the movement of the wearer’s arm winds the mainspring.
The system in an automatic watch self-winds the mainspring is a basic oscillating weight that turns causes a rotor to rotate on a pivot. This mechanism is attached to a ratcheted winding mechanism.
As the wearer’s arm moves backward and forwards, the weight oscillates, which causes the rotor to turn on the pivot and the winding mechanism to turn, which loads the mainspring.
The most basic automatic winding mechanisms wind the mainspring while the weight swings in only one direction.
More advanced units have two oscillating weights, which are activated separately depending on which way the arm moves. These models wind the mainspring irrespective of which direction the arm moves.
Most mainsprings can be wound to a state where the watch will run for two days, ans so it can be left overnight and will continue to operate into the next day.
Automatic watches retain the winding crown, which allows for the manual winding of the watch if it is not regularly worn.
The Advantages And Disadvantages Of Automatic Watches
There are several advantages to automatic watches (and a few disadvantages.)
The advantages of Automatic watches are listed below.
- Automatic watches do not have to be manually rewound.
- There is no battery required in an automatic watch.
- High-end watches have a sweeping second hand and very smooth movement.
- High-end automatic watches are very reliable and need minimal maintenance.
The disadvantages of Automatic watches are.
- Automatic watches only hold the mainspring “wind” for forty-eight hours.
- High-end automatic watches will lose approximately one second per day, double the time loss compared to a kinetic watch.
- Automatic watches are more expensive than the equivalent manual watches.
How Do Kinetic Watches Work?
Kinetic watches use a very different technology to store energy than conventional automatic winding and mechanical movement watches.
The technology used to generate the energy is very similar to that used in conventional automatic winding watches.
Kinetic energy from the movement of the arm (when wearing the watch) causes the rotor to rotate.
The system includes the oscillating weight (called a peso oscillator) that turns the rotor on a pivot. Instead of winding the mainspring, the rotor is connected by a large gear to a pinion, which is turned. As the wearer moves during everyday activities, the pinion turns at exceptionally high speeds.
Depending on the model, kinetic watch pinions can rotate at speeds up to 100,000 rpm. When the pinion achieves these speeds, it generates an electric charge.
This generated electrical charge is stored in a capacitor and is used to recharge the battery, called the ESU (Electrical Supply Unit.)
The ESU functions similarly to a normal lithium-ion battery, providing a stable voltage to power the quartz movement.
This enables the watch movement to function very stably, provides high accuracy, and is continually recharged by the pinion.
The Electrical Supply Units used in the first generation of kinetic watches used capacitors to store electrical energy. The energy is subsequently released to power the watch’s mechanism at a regulated and stable voltage.
Later generations use a Lithium-Titanium ion battery, which provides greater power reserves for several months on some models.
One of the unique features of modern kinetic watches is that they will never overcharge the battery, as they have a safety cut-off feature built-in within the generating system to stop this.
Kinetic watches can also be recharged by turning the crown like a mechanical watch mainspring is wound up.
What Technology Activates The Kinetic Watch?
The stored current powers the watch’s standard quartz mechanism.
A current causes oscillations in a quartz crystal which vibrates 32400 times a second.
A sensor counts off these oscillations, and every second sends a current to an electromagnet which advances the watch’s second hand by a single unit. This is why the second hand appears to tick.
The second hand is tied to the minute hand, hour hand, and date mechanism.
Unlike an automatic watch which will unwind in two days, the battery charge in a kinetic watch can last several months if the watch is stored.
The Advantages And Disadvantages Of Kinetic Watches
There are several advantages to kinetic watches.
The advantages of kinetic watches are listed below.
- Kinetic watches can be left in storage for months and still display an accurate time.
- Kinetic watches use accurate quartz technology, which will only lose 15 seconds in time over thirty days.
- Most kinetic watches have indicators showing the amount of power used and how much is stored within the watch.
- Some kinetic watches reset themselves even if they have been stored and not recharged for more than a year.
The disadvantages of kinetic watches are.
- The mechanisms are a little heavier than manual and automatic mechanical watches.
- A kinetic watch’s main capacitor eventually wears out and must be replaced.
- Kinetic watches are slightly more expensive than the equivalent automatic watches.
Conclusion
Kinetic and automatic watches generate energy similarly; however, kinetic units store the energy in batteries, and automatic watches store the energy in the unit’s mainspring. Kinetic watches retain power for months, while automatic watches only retain energy for 48 hours.
