*Last modified: 2023-11-12 08:53:47*

Well it hasn't stalled yet, that's good news. It seems pretty resistant to stalling if I even press my finger
against it, and even once stalled manually it still won't run backwards and starts up again on its own.
So the *performance* in the current state is acceptable.

However it currently has the big electromagnet in series with one of the coils, and it gets even hotter than it did before.

I've ordered a 9v transformer, maybe this will be better. Failing that, I can add a fan like Jay suggested.

In the mean time, it would be good to understand why the electromagnet works, and see if I can come up with some sort of circuit that will give a more convincing phase shift on 6v, and see if the clock will run on 6v after all.

I can't believe there are no decent DuckDuckGo results on how to phase-shift an AC supply by a given angle. Surely this is something other people have wanted to do? ChatGPT says:

To achieve a 90-degree phase shift in a 50Hz AC power supply, you can use a component called a capacitor or an inductor, depending on whether you want the phase shift to be leading or lagging.

Capacitor for Leading Phase Shift:

- Connect a capacitor in series with the load.
- The formula for calculating the capacitive reactance (Xc) is Xc=1/(2.pi.f.C), where f is the frequency (50Hz in your case) and C is the capacitance.
- To achieve a 90-degree phase shift, the capacitive reactance should be equal to the load impedance.
- Xc=Zload
Inductor for Lagging Phase Shift:

- Connect an inductor in series with the load.
- The formula for calculating the inductive reactance (Xl) is Xl=2.pi.f.L, where f is the frequency (50Hz in your case) and L is the inductance.
- To achieve a 90-degree phase shift, the inductive reactance should be equal to the load impedance.
- Xl=Zload
Keep in mind that the actual impedance of the load may include resistance (R) along with any reactance. The total impedance (Zload) is given by:

Zload = sqrt(R^2 + X^2)

Is this right? How can I work out the impedance of my load? I'll just measure the resistance for now.

I measured about 30 ohms across the coil of the stepper motor.

I asked it about a 91 degree phase shift and it said to set Xc to Zload * tan(91 degrees), which implies that for 90 degrees it should be Zload * tan(90 degrees), but it says to use just Zload, and tan(90 degrees) is not 1. Oh well, let's continue.

```
Zload = 30 ohms
Xc = Zload = 1/(2.pi.f.C) = 1 / (2 * 3.142 * 50 * C)
30 = 1 / (100.pi.C)
100.pi.C = 1/30
C = 1/(3000.pi) = ~0.0001 Farads = ~100uF
```

So I want to try a 100uF capacitor in series with the load. I think that is pretty big. My "104Z" (big ones) are 100nF, which is a factor of 1000 too small, which explains why I didn't get any different results no matter which capacitors I used. So I'd be looking for some marked "107" I think.

Most of the capacitors that I can find with that much capacitance are electrolytic, which is no good for AC.

There are some available described as "motor start" capacitors. I've ordered one. I think it is bigger than I need because it is rated for 250v, but if it works it works. In the mean time I can try and rummage around and see if I can find a non-electrolytic capacitor a bit bigger than 100nF.

Disheartened by the trouble I am having making these small parts, I want to lay out a new design using a larger escapement and a larger balance wheel.

I still intend to "finish" the escapement prototype I'm working on at the moment, in the sense that I want to make the escape wheel pinion and try running it with a weight. But I don't expect it to work, and I won't put much effort into making it work. Just consider it good experience in making small parts, and move on.

Maybe it would be a good idea to make a 2x scale prototype of the actual watch, but 3d printed where possible. Can I print module 0.8 gears?

Yes, actually, looks reasonably decent:

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