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4 Hz is 14,400 BPH. A usual beat rate for an old pocket watch is 5 Hz 18,000 BPHThat is a big question.
A timing machine listens to five knocks or shocks in the escapement in the running of the watch.
The escapement What is an escapement? The escapement is a distributing organ. It releases energy to the regulating organ in equal measured increments. It sustains oscillation by delivering energy via the mainspring barrel and gear train. Working in tandem with the regulating organ, the...slideplayer.com
Look at slides 37 to 40.
These impacts, in relation to the frequency of the watch (4Hz or 28,800 BPH for example) are compared to a source timing signal, usually a quartz timing reference.
The timing of these impacts also determines the beat error. The escapement is most efficient when in beat, that the impacts to both sides of the pallet fork are equal in timing, which indicates that the impulse stone is centered in relation to the escapement. When the impulse stone is favoring one side or another, the watch is out of beat, as one side is favored and is less efficient.
You can hear beat error in clocks with a pendulum. The sounds will be out of sync with each other. When in beat the tick tock of a clock will be equal.
This is keeping is simple.
I apologize, but your math is off. A frequency is a measurment of one oscilation per second.4 Hz is 14,400 BPH. A usual beat rate for an old pocket watch is 5 Hz 18,000 BPH
I stand corrected! My maths is indeed off. I am confusing beats with cycles per second. It’s rather late here. Brain not working!I apologize, but your math is off. A frequency is a measurment of one oscilation per second.
Consider a pendulum. From the center point it recieves an impule and swings to one direction, slows, stops, comes back to center where it recieves a second impluse, slows, stops and returns to center. This would be one oscillation, but two beats.
If a watch runs at 4hz, it has eight beats per second.
8 beats per second times 60 seconds = 480 beats per minute.
480 beats per minute * 60 minutes = 28,800 beats per hour.
Karl,Dewey Clark has written a very comprehensive document on static and dynamic poising on this matter. I highly recommend finding and reading it.
Beat error is another common adjustment where vintage watches usually rely on rotating the hairspring collet on the staff and some modern movements have a moveable stud carrier to accomplish the same. Then comes more involved and delicate adjustments such as correcting aspects leadning to variance in beat error depending on the position of the watch or position of the regulator arm, which is also something a time grapher will tell you.
Finally, a timegrapher with a "paper strip" function will show you a line of dots where you will be able to spot variances in rate that are inconsistent in relation to the rotation of a certain wheel or pinion, making the troubleshooting process a little easier and provides clues for your Sherlock Holmes like horological inductive reasoning. .
Best of luck!