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Denis G. Denis G. is offline
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Default oh turds! compressor motor starting cap's 'blown out' but it's a"non-standard"

On Oct 8, 9:03*pm, dave wrote:
my ancient 4hp sears craftsman air compressor needs a starting
capacitor, I've determined (through a process of elimination). I still
have the original owners manual, and the capacitor is "part of the
motor", not shown in the parts blowup, or parts list, as a seperate
orderable part. further, the friggin' thing seems to be a 'non-standard'
mfd rating, too (it doesn't 'fall into' any capacitor size-groups of any
maker's starting cap's I can find online. matter of fact, it's not even
close):

the one in it now is
110 volt, 485-580 mfd
mallory #139852-49
seems a slightly non-standard SIZE as well:
diameter: 1 13/16ths inch, and
length, overall, excluding 'spades': hair over 4 5/16ths (but clearly
under 4 3/8ths)

atttempts to locate same by the mallory part number on it entirely
unsuccessful. so (physical size and 'look' issues aside) can I "daisy
chain" two cap's and achieve the same net effect, somehow? appearance
"not an issue", I just need a working compressor. I know I can replace
the cap with a higher voltage cap, and that'd be fine (maybe even
desireble) but what about the mfd rating? if I must, is it best to go
'bigger mfd numbers' or lesser?

thanks for tips on this, guys :-)


It looks like the value of the cap is not that critical. They give
you a range 485 to 580 microfarads. The average value is
approximately 540 microfarads. If you order from McMaster Carr, this
should work: http://www.mcmaster.com/#7245k114/=3z7b3b