Many people add watches to their collections because of the intricate mechanisms and ingenious ways the watchmakers have made different systems work. When a chronograph is included in a watch mechanism, it adds complexity and fascination in working how it functions.

It is possible to leave a chronograph running, and it won’t damage the unit. While leaving the chronograph running permanently may cause it to wear faster, the main problem is that this type of usage will increase the power consumption and cause the batteries to need replacing sooner.

While it is possible to keep the chronograph running, there are some good reasons why it is not the optimal thing to do so.

You Can Leave A Chronograph Running

While it is possible to leave a chronograph running,

there is rarely a need to keep it running permanently, and it is prudent to deactivate the chronograph function deactivated when not in use.

For the following reasons, keeping the chronograph running continuously is not recommended:

  1. The large second hand of the chronograph watches stops when it is not timing which makes it appear as if the watch has stopped.
  2. The large and small second-hand are two-stepping motors and consume a lot of power.
  3. A quartz chronograph battery can last for between three to four years under normal conditions if the timekeeping function has been turned off; however,  if the chronograph runs consistently, the battery will use nine times as much power.
  4. While a good quality chronograph is designed to measure elapsed time over twelve or twenty-four hours,  if it is left running, there will be an increased wear rate on the mechanism.
  5. A possible consequence is that the chronograph may need more maintenance at more frequent intervals.

Horizontally coupled gears (e.g., Omega Speedmaster Pro)  experience an amplitude drop of up to 40 degrees if the chronograph is run constantly. To prevent this, stopping the chronograph watch running when it is not being used is worthwhile.

Vertically coupled gears do not have this issue and are not affected by continuous running.

How To Operate A Chronograph?

A Chronograph is a category of watch that can be used as a conventional timepiece and a stopwatch.

Generally, chronographs can perform the following functions:

  1. Telling time.
  2. Displaying elapsed time.
  3. Calculating speed based on travel time.
  4. Calculate distance based on speed.

Most chronographs use a quartz movement and are only automatic on the most expensive watches.

Chronographs are started using the following methodology:

  1. To start a chronograph, press the indicated button on the watch.
  2. The chronograph is generally stopped by re-pressing the same button.
  3. Reset the chronograph by pressing the relevant button on the watch.

Most chronographs have three dials.

  1. The first shows seconds elapsed.
  2. The second shows minutes elapsed.
  3. The third shows hours elapsed.

The Tachymeter is the series of numbers around the circumference of the watch face.

The tachymeter can be used to calculate speed (based on travel time) or distance traveled (based on speed).

How Do Chronographs Work?

There are two main types of chronographs.

  1. A cam system.
  2. A column wheel.

These refer to the mechanism within the chronograph that drives all functions.

The Cam System

The cam system consists of an upper and lower cam.

The Column Wheel System

The column wheel system consists of a gear with ratcheting teeth around it and corresponding columns sticking out of it.

Apart from the different mechanisms, the rest of the systems are very similar.

These two systems activate the different systems, as follows:

  1. The Start system.
  2. The Stop system.
  3. The return to zero function.

The Start System

The system below describes the action of a chronograph with a horizontal clutch.

  1. When the start button is pushed, it activates the main operating lever.
  2. The main lever pushes the intermediate operating lever, which pushes the lower cam clockwise.
  3. This action causes the cam jumper spring which falls into an indentation on the lower cam and lock into place.
  4. The movement activates the Intermediate chronograph lever
  5. This action causes the chronograph driving wheel to mesh with the  Intermediate chronograph driving wheel.
  6. The wheels are moved forward and make contact with the center chronograph wheel, which is attached to the rotating second-hand dial on the screen.
  7. The rocking lever spring keeps the tension on the rocking lever and returns the intermediate operating lever to the starting position when the button is released.

The Stop System

Most actions are reversed when the button is pressed for the second time.

  1. Pushing the start button reactivates the main operating lever.
  2. The main operating lever pushes the intermediate operating lever, which pushes the lower cam ANTI clockwise.
  3. The movement activates the Intermediate chronograph lever
  4. This action causes the chronograph driving wheel to move away from the  Intermediate chronograph driving wheel.
  5. The chronograph driving wheel and the  Intermediate chronograph driving wheel remain meshed but are moved backward and out of contact with the center chronograph wheel.
  6. The brake lever is activated, pushes against the center chronograph wheel, and stops turning, allowing the user to read the elapsed time.

The horizontal system can have trouble engaging which causes the center chronograph wheel to jump at the start.

To overcome this, the vertical clutch system was developed.

The difference between the vertical system is that the Intermediate chronograph driving wheel drops down vertically instead of from the side.

This system is more complex and, therefore, more expensive.

The Return To Zero Function

When the return to zero pusher is depressed, the following happens.

  1. The buttons cause the locking pin to move out of the way.
  2. When the locking pin is moved out of the way, it disengages with the hammer.
  3. A “heart” cam is mounted on the center chronograph wheel and a second wheel.
  4. The heart cams correspond with the second and the minute hands.
  5. The hammer swings out and connects with the two heart cams, forcing them to move into an orientation corresponding to zero.


The watch’s chronograph mechanism is intricate and designed to measure elapsed time for a relatively short period. While it will not damage the watch to keep it running, it is a waste of battery capacity and, over time, will cause a higher wear rate.


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