Beat error on vintage timegrapher paper trace

[GuyMontag]

I am reading Fried's The Electric Watch Repair Manual and in the section on the ESA 9154 it says, "As the mechanical beat has a negligible influence in this calibre, a distance up to 5mm between the strokes forming the timing machine traces can be tolerated".

Is a 5mm distance between the 'strokes' equivalent to a 5ms beat error?

[JohnR725]

The simplistic answer would be no. Typically with the paper tape timing machines they did not tell you that X number of millimeters equals so many milliseconds. I have only seen one manual that does have a scale that tells you how many milliseconds corresponds to their ruler that they include. Then the milliseconds spacing will change depending upon which rate you're on.

[praezis]

Sometimes yes.
You can find out yourself. Usually the manual tells the rotation speed of the drum, e.g. f=30 Hz @ beat x. The width of the paper equals 1/f sec. From here you can find your beat error.

Frank

Edited March 8 by praezis

[Neverenoughwatches]

6 hours ago, GuyMontag said:

I am reading Fried's The Electric Watch Repair Manual and in the section on the ESA 9154 it says, "As the mechanical beat has a negligible influence in this calibre, a distance up to 5mm between the strokes forming the timing machine traces can be tolerated".

Is a 5mm distance between the 'strokes' equivalent to a 5ms beat error?

No 5ms is the time difference between the impulse reaching its dead on beat point, from one beat to its opposite beat. The distance travelled difference will change depending on what the amplitude is at that time.

[JohnR725]

24 minutes ago, praezis said:

Sometimes yes.
You can find out yourself. Usually the manual tells the rotation speed of the drum, e.g. f=30 Hz @ beat x. The width of the paper equals 1/f ms. From here you can find your beat error.

The amusing problem is the service manual does not specify a timing machine.  Not specifying an exact timing machine considerably that would be some variations but probably on paper tape machines they're all approximately the same. So that you don't have to do the math I've scanned the transparent ruler that comes with the Greiner timing machine manual. Although I don't see the frequency we need which is  28,800. Which I believe would be the one labeled 36 although I am mathematically challenged so Frank may have to verify that that is indeed correct.

 I'm also attaching the service manual at least what there is of it in PDF form. 

Then for those nitpicky observant people of exactly how big is the image versus the original image I will measure the last one Number 36 5 mm  Is equal to 4 ms exactly.

3540_ETA 9154.pdf

[praezis]

1 hour ago, JohnR725 said:

Frank may have to verify…

In John‘s picture, left paper: drum rotates @ 30 Hz (see circle). That is the speed, if shown beat rate group was selected.

Assuming the paper width is 33mm. Then the paper width equals 1/30 s = 33ms or 1mm equals 1ms.

If the paper is 40mm:
1mm equals 33ms/40mm * 1mm = 0.825ms

If nitpicky, replace paper width by printing width, if not the same.

You can make cardboard rulers for your machine like Greiner showed.

[RichardHarris123]

Where does the 30Hz refer to?  I'm asking because the outer edge of a rotating object is spinning faster than further towards the axis of rotation. 

[praezis]

1 hour ago, RichardHarris123 said:

Where does the 30Hz refer to?  I'm asking because the outer edge of a rotating object is spinning faster than further towards the axis of rotation. 

It is the rotating frequency of the drum: 30 rotations per second.

[GuyMontag]

Thanks guys! The collective knowledge here is impressive.

 

7 hours ago, JohnR725 said:

he amusing problem is the service manual does not specify a timing machine.  Not specifying an exact timing machine considerably that would be some variations but probably on paper tape machines they're all approximately the same. So that you don't have to do the math I've scanned the transparent ruler that comes with the Greiner timing machine manual. Although I don't see the frequency we need which is  28,800. Which I believe would be the one labeled 36 although I am mathematically challenged so Frank may have to verify that that is indeed correct.

 I'm also attaching the service manual at least what there is of it in PDF form. 

Then for those nitpicky observant people of exactly how big is the image versus the original image I will measure the last one Number 36 5 mm  Is equal to 4 ms exactly.

 

3540_ETA 9154.pdf 2.24 MB · 2 downloads

Thanks for scanning that, very interesting. I hadn't really had an appreciation for how those old timegraphers worked.

 

5 hours ago, praezis said:

In John‘s picture, left paper: drum rotates @ 30 Hz (see circle). That is the speed, if shown beat rate group was selected.

Assuming the paper width is 33mm. Then the paper width equals 1/30 s = 33ms or 1mm equals 1ms.

If the paper is 40mm:
1mm equals 33ms/40mm * 1mm = 0.825ms

If nitpicky, replace paper width by printing width, if not the same.

You can make cardboard rulers for your machine like Greiner showed.

So it sounds like up to around a 4ms to 5ms wold be acceptable and I'm getting around 1 to 1.5 so I'm not worrying about it. Not that I would have been able to do anything about it anyways