Too much capacitance on capacitor start motor??
Too much capacitance on capacitor start motor??
(OP)
Is there such a thing as having too much capacitance on a capacitor start motor? In other words, is it possible to have too many uF worth of start capacitors?
What I have run into is a 15 HP 1ΓΈ 3450 RPM centrifugal fan. Some of the run capacitors where a bit corroded at the terminals so I replaced them. In the process, I checked the starts too. One was bad so I replaced it with an identical start (216uF 250V). Upon starting the fan, the new capacitor promptly blew its top (the other 2 where cool to the touch yet).
I double checked the wiring and installed another. Same results. Each time the fan would start, but not without blowing the newly added capacitor. In all I toasted 3, till finally I started it on the remaining 2 and left the third off. Seemed to work great, at least for now.
Any ideas what might have been doing this?
What I have run into is a 15 HP 1ΓΈ 3450 RPM centrifugal fan. Some of the run capacitors where a bit corroded at the terminals so I replaced them. In the process, I checked the starts too. One was bad so I replaced it with an identical start (216uF 250V). Upon starting the fan, the new capacitor promptly blew its top (the other 2 where cool to the touch yet).
I double checked the wiring and installed another. Same results. Each time the fan would start, but not without blowing the newly added capacitor. In all I toasted 3, till finally I started it on the remaining 2 and left the third off. Seemed to work great, at least for now.
Any ideas what might have been doing this?





RE: Too much capacitance on capacitor start motor??
Just a thought,
Raisinbran
RE: Too much capacitance on capacitor start motor??
RE: Too much capacitance on capacitor start motor??
RE: Too much capacitance on capacitor start motor??
respectfully
RE: Too much capacitance on capacitor start motor??
RE: Too much capacitance on capacitor start motor??
Is it possible you got a single electrolytic cap instead of a dual? It could be that the markings would look similar. But the single elctrolytic cap I think would have a + / - marked on it.
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RE: Too much capacitance on capacitor start motor??
"electrolytic capacitors by themselves cannot tolerate ac"
duhhh, Sorry
=====================================
Eng-tips forums: The best place on the web for engineering discussions.
RE: Too much capacitance on capacitor start motor??
RE: Too much capacitance on capacitor start motor??
You have the symptoms of over voltage so by all means try the 330 volt caps.
respectfully