Question about using run/start capacitors

DrewE wrote:
Start capacitors (and run capacitors) for single-phase induction motors all work by altering the phase angle for different motor windings; without that, the motor would not start at all. (There are some induction motor designs that use other means to generate the phase shift, but that's a different matter entirely. Probably the most common of them is the shaded-pole induction motor used in many relatively low-power, low-starting-torque settings.)

Micro-air sells and has pictures of their boards out of their enclosures on their web site. Theirs are clearly a lot more complex than the one you show above.

I would guess the gizmo you pictured probably just acts as an AC current limiter, based on an opamp/comparator that samples the current via one of the power resistors and switches whatever semiconductor switching device that is on the heatsink. If so, it seems like a good way to kill off a pesky air conditioner compressor you didn't really want to be carrying around on your roof. I can't make out the part numbers on the little IC, so I may be way off base in what it does or how it works.

I agree, it is nowhere near a clone of the micro air. I have the micro air. it has way more circuitry, a learn circuit with reset mode, AND guess what, it's own starting cap to replace the start cap in the factory AC unit. And it's wiring is more complex. It also has a delay circuit to let the fan start and get the generator rpm up a bit before it kicks in to start the AC compressor.

And the micro air has an overload detector that kicks in if it sees the compressor power source appearing to overload and will kick off the compressor before it is damaged.