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Re: power factor correction?



Original poster: "Crow Leader by way of Terry Fritz <teslalist-at-qwest-dot-net>" <tesla-at-lists.symmetric-dot-net>

I've seen applications where electrolytic motor start caps (yes the
phenolic cases, and a blow from a hammer shows they were electrolytic) are
used as run caps in short duty devices, such as change machines. I
converted the bill feed mechanism from an 1980's Rowe International change
machine into a door opener. The motor would overheat and cutout and the
start cap never even warmed up, and this was after 15 minute runs of
smashing pop cans in the door. I don't believe motor start caps blowup
after 2 seconds of use. They can't be that inefficient, DC electryolytics
take along time to warm up under heavy ripple.

KEN

On Mon, 7 Jul 2003, Tesla list wrote:

 > Original poster: "by way of Terry Fritz <teslalist-at-qwest-dot-net>" 
<Tesla729-at-cs-dot-com>
 >
 > In a message dated 7/7/03 4:07:52 PM Pacific Daylight Time,
 > tesla-at-pupman-dot-com writes:
 >
 > >This describes my cap from the dump! Mine is the size of a fat, black soda
 > >can.
 > >Well what now? It works so "if its not broke don't fix it".
 > >Unless, that is, I can expect to get better sparks.
 > >
 > >Read you later
 > >Josh
 >
 >
 > Josh,
 >
 > Can you tell us what the voltage/capacitance rating of your mystery
 > "black soda can" cap is? If it is a non-precise cap rating (ex: 145-210 ufd)
 > as opposed to a single 35 uFD or 50 uFD rating, then it most likely is
 > a non-polarized electrolytic START cap. If this is indeed the case, then
 > the real mystery is why isn't your cap smoking within 15 seconds ??
 > The only thing that I could figure is that the voltage rating is much
 > higher than what you are using it for, so the short duty cycle design
 > doesn't come into play as much (i.e. like you are applying to 120 volts to
 > a start cap unit rated for 330 VAC)
 >
 > David Rieben
 >
 >
 >