Two Ways of Looking at a Thing (II)

Take a look at this:

An Electrical Switch, View 1

As I mentioned yesterday, this is a 24-volt double pole contactor for an air conditioning unit.

But it’s also akin to a computer program. It’s a simple mechanical switch, but it functions like any method or function in an application. It takes input from the main circuit board, a 24 volt current that triggers the switch. When the switch is triggered, the condenser and compressor come on and make the magic happen. When the current stops, the switch opens and the external unit shuts down.

So. What can happen to impede this process? How would you test it?

Of course, one would send a 23 volt current along to see if it triggered. And then 25. And then, if one was really sadistic, one would pipe the electric version of Hamlet at it (which would explain why the lights in the building just dimmed).

What happens if the switch sticks in the partially on position? What happens if current travels between the contacts incorrectly (a shower of sparks and a bad switch, which explains why this one is on my desk and not in my air conditioning unit). In many cases, the problems you would find would be the result of installation issues, that is, deployment of this object. That’s when the wires can get hooked to the wrong screws and whatnot. What happens then? Hopefully, just a failure of the device and not a cascading catastrophe.

When you’re looking at an application, try visualizing it as a physical object with access points and egresses. What happens if you cross the streams? Is it only partial protonic reversal? If so, log a defect.

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