[GreenKeys] Lorenz Motor Speed Control

[Jeffrey D Angus]

Today was a good day.
As a career engineering technician, I used to tell my engineers "If this
stuff worked, you wouldn't need me." Well, as the engineer on this
project, I needed me. ;-) As with any project, what looks good on the
drawing board doesn't always go quite like it was planned. Little
things like the Set and Reset lines go to ground, not Vcc. Or that Q is
NOT equal to /Q and things like "Oh, it triggers on the rising edge."
Then there's other little annoyances, like forgetting to solder a pin
on an IC, or folding a pin up under the chip instead of inserting it
into the socket. And lastly, getting the design speed wrong. 2727
RPM instead of 1500 RPM. That was entirely my fault for missing
the part in the Lorenz manual that clearly stated 1500 RPM.

This evening when I turned out the lights at the shop at 9 PM and
went home, everything was working as it should be except for the
speed. That's easily correctable with a new reference oscillator.

But for now, here's a short video of the controller doing what it's
supposed to. Acting like a centrifugal switch to speed up or slow
down the motor around a giving set point. The first half is with it
running at 495 Hz +/- 10% and switching at 1010 uS, The second
half is it running at 450 Hz +/- 10% and switching at 1111 uS. The
top trace is the output to the solid state relay. The lower trace is
the speed sensor input sweeping back and forth +/- 10%.

Once I get the reference oscillator set right for 1818 uS and 2000
uS, I'll install it in the Lorenz Lo-15b and see if it does what it's
supposed to do. At this point, I have a fairly high confidence rate.

As I mentioned at the beginning of this, the goal here is to be
able to switch back and forth between 45 and 50 baud operation
with the flick of a switch. Without having to do any adjustments
requiring a tuning fork, strobe or tachometer.


-- 
Jeff-1.0
wa6fwi
http://www.foxsmercantile.com

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