I used the keyboard approach originally and then bought the tuning fork because it was relatively inexpensive, and like you said, a very neat accessory for the Teletype. Also, the governed motor wreaked havoc with the scope and triggering - even on a separate outlet and power filter.

When adjusting with the keyboard, there is a very good chance the 1 and 0 bits are not perfectly symmetrical. Type an "R" or "Y" and measure from falling edge to falling edge (or rising to rising) and shoot for 44 ms (two 22ms bit times).

Mike


On Monday, February 20, 2023, 08:37:29 AM CST, Eric Moore <mooreericnyc@gmail.com> wrote:


Thank you John, I was told a synchronous motor would need a new gear set.

I am concerned about the rubber part, is there a manual for these motors I can follow? I need to open it up and make sure the rubber looks ok.

I am torn on a tac or a tuning fork... I am leaning toward a tuning fork since it is such a neat accompaniment to this artifact, and as someone smartly mentioned I can dial in motor speed with the keyboard and a scope.

-Eric




On Mon, Feb 20, 2023, 8:24 AM John Nagle <nagle@animats.com> wrote:

 > From: Eric Moore <mooreericnyc@gmail.com>
 > Subject: [GreenKeys] Governed model 14 motor

 > Hello, I have a model 14 KTR that I have been working on.
 > I am looking for information on the governed motor it uses, picture
 > attached.
 > I am told it used a tuning fork for adjustment? Does anyone have one of
 > these, or a set of instructions?
 >
 > Thank you for any help!

Here's the tuning fork:


https://www.ebay.com/itm/vintage-military-teletype-tuning-forks-Nanasi-JC-Deagan-Jerico-180vps-120vps/124333026125

The motor has a centrifugal governor
to maintain the speed at 1800 RPM. The tuning fork is
to help adjust the governor.

The idea is that you look at the striped wheel through
the slits in the tuning fork, and adjust the speed until
the slits are stationary. It's like using a strobe lamp.

The little lever next to the flywheel on the motor adjusts
the speed. It presses against a rubber wheel on the flywheel
which turns a screw to increase or decrease the speed of
the motor.

I think you want a 90 or 180 or 360 vps tuning fork to get 1800 RPM.
The motor's data plate says 1800 RPM. That's 30 revs/second,
so if there are 12 white bars, you'd want a 360Hz flash.
You can use a strobe lamp if you have one around. Goal is
to get the motor running at 1800 RPM.

There will be a lot of arcing and RF hash. The model 14
is from the 1920s, before the widespread use of radio.
Later models have some filtering, but the originals do not.

Most Teletype machines still in use have a synchronous motor running at
1800 RPM, which makes everything simpler. Consider getting
a synchronous Teletype motor. It's an easy swap. These machines
are very modular.

                        John Nagle
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