Quote:
Originally Posted by kuehl
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That "inductive kick" that sent the diode's plastic encapsulation into "orbit" (luckily no one lost an eye) should have been isolated from the diode circuit through the opening of the thermostatic switch.
What kind of poor circuit design are you selling that exposes the circuitry to such a huge electric surge?
I see. You used a dual color LED, green to indicate the system is on, enabled, with a red LED element connected to clutch coil side to indicate that the compressor is cycled on. Even a junior engineer could have advised you of the probable outcome of that circuit design.
"..even-better-service..." Yes, most certainly so, especially when you screw up such a simple design aspect in a way wherein someone might lose an eye. Did you issue a TSB right away, recall...? Any attempt to notify customers who had previously purchased your flawed circuit design..?
How did you get that far along with such a FLAWED design absent someone noticing the LEDs bright flash, as OP obviously had, each time the compressor clutch circuit was opened? Or was it observed but without understanding of what it meant, pro-tended?
Did you know that using a simple high power diode to "swamp" the compressor clutch coil inductive kick might well result in premature failure of the clutch? That approach results in a "slow" clutch release. To prevent that possibility you need a high power resistor of fairly low resistance in series with the diode. And a high voltage low microfarad value capacitor in parallel with the diode resistor to slow the inductive voltage risetime would also help.
The fix you should have used (now use?) is a 16 volt high power zener diode (motorcycle alternator voltage output regulator, voltage LIMITER) in parallel with the RED LED and its current limiting resistor.