Quote:
Originally Posted by mrd
Can you give any more details on the interface and control of the EEV?
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The EEV is simply a 4 phase (or 8 half-phase) unipolar stepper motor. There is zero public information on this EEV, so the hardest part was figuring out the phasing.
Basically I lubed up the valve and put it in the coil upside-down (pipes up). When the valve wound closed internally the stator stopped turning inside the valve, and thus the entire valve body rotated. I could then see the individual steps and change the sequencing in the software until I got it right.
The valve has about 45 steps to begin opening, and then about 450 usable steps of valve travel. About another 100 steps and it starts clicking as it runs off the end of the thread. Worst case I was going to sacrifice one of them so I could watch the stator rotate, but I didn't have to thankfully.
I'm *hoping* it'll flow about 7KW worth of refrigerant (It needs about a 1.6-2mm orifice to do that). If not then I have a much bigger one I can try. That one will be a lot easier to figure out as the valve motor head unscrews and you can physically see the pin rise and lower as the motor rotates (it pushes on a bellows in the valve which moves the valve in the body).
Now the dilemma, Valentines night with a cool house and a hot wife, or AC Hacking with a warm house and a cold wife...