Capacitor Polarity


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Old 07-11-13, 04:44 PM
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Capacitor Polarity

I have a wiring diagram for an air conditioning unit. On the diagram the run capacitors indicate that a "red dot" on the capacitors indicates which corresponding colored wire attaches there. However, the capacitors are rusted (an outside air conditioning unit) and no "red dot" can be seen on either capacitor nor any other indication of polarity. I can make out that the capacitors are rated at 370VAC. That being the case, AC vs. DC, can I not use non-polarized 370VAC capacitors with correct uF for replacement? Thanx.
 
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Old 07-11-13, 05:04 PM
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You are correct. The capacitors used in air conditioning applications do not have a polarity, so the polarity of the wires doesn't matter. However, be aware that if you have a dual capacitor (2 capacitors in one package), typically they have 3 terminals, with one of them being the common. In this case, it does need the common wire connected to the common terminal.
 
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Old 07-11-13, 06:35 PM
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Thanx Bob. I don't know why Ruud made a distinction with the "red dot" on the wiring diagram. Both the compressor and the fan capacitors are single so I don't have to worry about polarity in that sense.
 
 

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