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The right Cap for the job



Original poster: "Matt Skidmore by way of Terry Fritz <twftesla-at-qwest-dot-net>" <fox-at-woozle-dot-org>

Since today was my last day at the summer job i took the oppertunity to
research the right cap to use for a pole pig. i've be able to locate some
very compelling deals and decided to figure out what capacitance i would
need.

Ive been searching for 2 different types of pig voltages to see what i
could find. ive looked for 14400 and 19900 volt pigs both at 10kva. for
the 14400v pig i just ran a loose va divided by voltage to get 694mA
output and 502 mA output for the 19900 pig.

i started configuring MMCs using the geek cap specs and then tried
selecting various other caps from the cornell dub 942C cap series. i based
my prices off of the Richardson Electronics website (catalog.rell-dot-com) and
tried to find the cheapest possblie capacitor for the above mentioned
transformers.

my calculations show that for the 14400v 10kva pig the 1600v 0.56uF cap
(942C16P56K) yeilds the lowest cost. and the 1600v 0.69uF cap (942C16P68K)
would be the better for 19900 pigs.

no research was performed on the performance of the overall capaitor.
since all of these capacitors are of the same series and type i would
expect similar results from the group.

by request i have a color coded html table too.


Transformer 		10 KVA		10 KVA
Output (V) 		14400		19900
Output (mA) 		694		502
Input (V) 		240		240
Input (A) 		42		42
Capacitance Reqired (uF) 0.128		0.067



942C20P15K
Voltage 		2000
Capacitance (uF) 	0.15
Price ($) 		2.52


942C16P68K
Voltage 		1600
Capacitance (uF) 	0.68
Price ($) 		4.27


942C16P56K
Voltage 		1600
Capacitance (uF) 	0.56
Price ($) 		3.69


942C16P47K
Voltage 		1600
Capacitance (uF) 	0.47
Price ($) 		3.38



Transformer 			14400 		19900

942C20P15K
Caps Per String 		11 		15
Number of Strings 		10 		7
Total Number of Caps 		110 		105
Total Capacitance (uF) 		0.1364 		0.07
Rated Voltage (V) 		22000 		30000
Total Cost ($) 			277.2 		264.6

942C16P68K
Caps Per String 		13 		18
Number of Strings 		3 		2
Total Number of Caps 		39 		36
Total Capacitance (uF) 		0.1569 		0.0756
Rated Voltage (V) 		20800 		28800
Total Cost ($) 			166.53 		153.72


942C16P56K
Caps Per String 		13 		18
Number of Strings 		3 		3
Total Number of Caps 		39 		54
Total Capacitance (uF) 		0.1292 		0.0933
Rated Voltage (V) 		20800 		28800
Total Cost ($) 			143.91 		199.26


942C16P47K
Caps Per String 		13 		18
Number of Strings 		4 		3
Total Number of Caps 		52 		54
Total Capacitance (uF) 		0.1446 		0.0783
Rated Voltage (V) 		20800 		28800
Total Cost ($) 			175.76 		182.52