859 lines
40 KiB
Plaintext
859 lines
40 KiB
Plaintext
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(word processor parameters LM=8, RM=75, TM=2, BM=2)
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Taken from KeelyNet BBS (214) 324-3501
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Sponsored by Vangard Sciences
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PO BOX 1031
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Mesquite, TX 75150
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There are ABSOLUTELY NO RESTRICTIONS
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on duplicating, publishing or distributing the
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files on KeelyNet except where noted!
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October 4, 1993
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CAPACITR.ASC
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--------------------------------------------------------------------
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This file shared with KeelyNet courtesy of Bert Pool.
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--------------------------------------------------------------------
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High voltage capacitor construction, by Bert Pool.
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First of all important warnings and disclaimers:
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High voltage capacitors are very dangerous for several obvious
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and some not-so-obvious reasons. Most experimenters know that a
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capacitor can contain a significant voltage even after power has
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been removed.
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Discharge all capacitors with a jumper cable before working on
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them. When discharging large capacitances, the jumper cable
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needs a high wattage 100 ohm resistor to limit discharge current.
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EVERY CAPACITOR IN A "SERIES" DESIGN TESLA CIRCUIT MUST BE
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DISCHARGED SEPARATELY! SHORTING ONE CAPACITOR WILL NOT DISCHARGE
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OTHER CAPACITORS IN THE CIRCUIT!
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Voltages and currents available on charged capacitors can be
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lethal. Use common sense. The capacitors described here are
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sealed and contain mineral oil. While mineral oil is not
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especially flammable, a catastrophic capacitor failure can result
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in pressure buildup and explosion if construction technique does
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not allow for release of pressure.
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Mineral oil will burn - a catastrophic capacitor failure can also
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result in the release of oil which could ignite. It is highly
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suggested that experimenters keep on hand a fire extinguisher
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rated for oil fires.
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Also, it is suggested that oil filled capacitor banks be stood in
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a metal pan large enough to contain the oil in case the capacitor
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container is breached or oil is released. This pan can prevent a
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mess, as well as help contain a potentially nasty fire!
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I have built over a dozen oil filled high voltage capacitors, and
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I have had several failures due to construction shortcuts or
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material failures and I have NEVER experienced a dangerous
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buildup of pressure or a fire - but I know it CAN happen and I
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take measures to be prepared for such an eventuality. Many high
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power Tesla coils use "power pole" transformers; these too are
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Page 1
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filled with oil and the same precautions for prevention of
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explosion and fire apply here too.
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As a high voltage experimenter, you take full responsibility for
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safe construction and operation of your capacitors and other high
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voltage devices.
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Be safe, be careful, use common sense!
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--------------------------------------------------------------------
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Keeping all these safety ideas in mind, presented is a method for
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building home-brew polyethylene capacitors which serve very well for
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Tesla coils, ZPE devices, etc.
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The original design is not mine, it was conceived by Richard Hull of
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the Tesla Coil Builders of Richmond (TCBOR). TCBOR has an excellent
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video showing step-by-step construction of this type of capacitor.
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Other available video tapes provide excellent info on Tesla coil and
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Tesla magnifier construction. Richard Hull may be contacted at:
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TCBOR,
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7103 Hermitage Rd,
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Richmond VA 23228.
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The capacitor described, using .0625 inch thick polyethylene will
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have a measured value of 0.0185 ufd with an a.c. working rating of
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7500 volts r.m.s. A .090 inch thick polyethylene dielectric
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capacitor will have a value closer to 0.010 ufd, and can be used in
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Tesla coil circuits using a power source up to 15 kilovolts a.c..
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As any coil builder knows, the resonant peak voltages go WAY above
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the source voltages! Power LOSS in one of these caps in a Tesla
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coil configuration is LESS than 0.5 watt per cap! Thus, they don't
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suffer from internal r.f. losses which translate into heat failure.
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A poly capacitor made with .060 poly should handle 36,000 volts d.c.
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and the .090 thick poly job should easily handle 54,000 volts d.c.
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These are very conservative ratings - good quality polyethylene
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might handle twice these ratings.
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Capacitors may be placed in series for higher voltage ratings,
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parallel for more capacitance.
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CAPACITOR FUNDAMENTALS:
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A simple capacitor consists of two conductive plates separated by
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an insulator. Capacitance is determined by the area of the
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plates, the distance between them and the "dielectric constant"
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of the insulator between the conducting plates.
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This dielectric constant is represented by a number called "K".
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On the next page is a table of materials and their "K" and their
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puncture voltages taken from the "Radio Amateurs Handbook":
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Page 2
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MATERIAL | "K" | PUNCTURE
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| | VOLTAGE PER
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| | MIL
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=============================================================
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AIR 1.0 240
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BAKELITE 4.4 - 5.4 300
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BAKELITE, MICA FILLED 4.7 325 - 375
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FORMICA 4.6 - 4.9 450
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WINDOW GLASS 7.6 - 8 200 - 250
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PYREX GLASS 4.8 335
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MICA 5.4 3800 - 5600
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PLEXIGLASS 2.8 990
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POLYETHYLENE 2.3 1200
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POLYSTYRENE 2.6 500 - 700
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PORCELAIN 5.1 - 5.9 40 - 100
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QUARTZ 3.8 1000
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TEFLON 2.1 1000 - 2000
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A vacuum or air has a "K" of 1. If you put a piece of teflon
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between your plates (same spacing), the capacitance will increase
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2.1 times and it will handle at least 5 to 7 times as much voltage.
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If you used a piece of good quality glass, the capacitance might
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increase 8 times! (the voltage rating would increase only slightly).
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The dielectric you choose will be determined by voltage, frequency
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(if using a.c.), durability (glass breaks very easily), cost and
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physical size.
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MATERIALS AND SOURCES:
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The capacitors we will build use polyethylene. Poly is very easy to
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work with, does not break, is inexpensive, readily available, has
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very good a.c. characteristics (very low loss), and has good high
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voltage properties. Mica would be even better, but it is VERY
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expensive and is not readily available.
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Glass is o.k. as far as availability and cost goes, but it has very
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high internal losses for Tesla coil use, compared to poly. Glass is
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also very fragile to work with. I've made glass capacitors weighing
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over 600 pounds -NEVER AGAIN! You just can't beat making capacitors
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out of polyethylene.
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Purchase two sheets of polyethylene sheet, 48 inches wide by 96
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inches long. Each sheet will be cut lengthwise into three sheets,
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each 16 inches wide. All together, you will have 6 pieces of poly
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16 inches wide by 96 inches long. This is enough material to make
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THREE capacitors.
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The thickness of the poly sheets is determined by the voltage you
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will be placing on the capacitor. You have to take into account
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whether you are using d.c. or a.c.
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If you are using d.c. voltage, calculate your poly thickness by
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using dielectric voltage rating of 600 volts per mil (one mil = .001
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inch). Some charts show that poly can handle 1200 volts per mil -
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Page 3
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Tesla coil experience shows that this value is NOT conservative
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enough, even taking peak-to-peak values into account!
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If you are using a.c., and especially with a Tesla coil, you have to
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de-rate the voltage ratings on the poly or you will have capacitor
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failure. For Tesla coils using input transformers from 9 kilovolts
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up to 15 kilovolts, use 90 mil thick polyethylene. If your input
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transformer is 7200 volts or less, you can use 60 mil poly.
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Polyethylene sheeting may be purchased in Dallas from
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Regal Plastics,
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2365 Merrell Rd.,
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Dallas TX 75229,
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Phone (214) 484-0741.
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Cost (8-83) is:
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.0625" thick 48" x 96" = 17.50 each x 2 = $35 plus tax
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.090" thick 48" x 96" = 30.00 each x 2 = $60 plus tax
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I've also bought .030" inch poly from
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Allied Plastics,
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4111 Billy Mitchell Dr.,
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Dallas, TX 75244,
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Phone (214) 392-2708,
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for $14.50 per sheet, not including tax.
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We will make our conductive plates out of aluminum roof flashing.
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You can buy a fifty foot roll of 14 inch wide aluminum roof flashing
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here in the Dallas area from Home Depot for about $22 (4-93). This
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is almost exactly the length you will need for three caps. The
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aluminum flashing, by the way, is about 10 mils thick. The Home
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Depot item identification # off my receipt is 099137150504 - $21.80
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(4-93)
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For a capacitor container, we will use 6 inch diameter sdr 35 PVC
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pipe cut into 19 inch lengths. I got mine at
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Southwestern Underground,
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1696 W. Northwest Highway,
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Irving TX 75014
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(214) 556-0188.
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It comes in 13 foot lengths, $1.25 per foot, or $16.25 + tax (2-93).
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You will also need flat "glue on" pvc end caps for this pipe; $4.40
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each, or $26.40 for six (enough for 3 caps). Do not get the rubber
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gasketed end caps - they are not flat on the end and the seals will
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not hold up while immersed in oil.
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You will also need pvc primer and cement to glue the end caps to the
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pvc pipe.
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You will also need some 1/4 inch thick clear plexiglass sheet
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scraps, each piece large enough to cut a 6 inch diameter circle.
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You will need plastic tie-wrap straps about 24 inches in length, or
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enough 12 inch straps to link together to form nine 24 inch long
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Page 4
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straps. Try to get straps that do not contain metal teeth inside
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the lock of the strap.
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To make connection to the aluminum plates you will need some #10
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screws, washers, and nuts. You will need two split-bolt electrical
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connectors to go on the top of each capacitor - Home Depot #
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032076146020, $3.33 each. You will also need 3 or 4 feet of high
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voltage wire to connect the split-bolt output connectors to the
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aluminum plates.
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You will need two inexpensive radiator drain petcocks (valves) from
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Chief Auto (#852079) for $2.99 each. We will use these valves to
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fill the capacitor with oil and/or attach a vacuum pump.
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Finally, you need a very high quality mineral oil to fill the
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capacitor. I use SnapLube-100 from Tulco Oil in Arlington Texas,
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(817) 640-0051.
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It comes in a five gallon re-sealable pail for $43.10, including
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tax. I've never had an oil related capacitor failure using this
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oil. SnapLube 100 is a highly refined non-carcinogenic oil containig
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NO PCB's.
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PCB's, poly carbonanted bi-phenols, are a very evil, nasty stuff
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which used to be used in high voltage oils - it is not something you
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want to come in contact with, especially if you ever expect to bear
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healthy, normally formed children. Any way, just about any good
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quality, low moisture mineral oil will work in these capacitors.
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ACTUAL CONSTRUCTION:
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BOTTOM PVC end caps:
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Glue two 1/2 inch by 1/2 inch square pieces of plexiglass stock
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three inches long across the inside bottom of the BOTTOM end
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caps. Make sure these two strips are at least 1/4 inch away from
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the walls of the plastic end cap! You have to allow space for
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the wall of the pvc pipe to reach the bottom of the end cap.
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The purpose of these spacers is to prevent the rolled capacitor
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from sitting directly on the bottom pvc end cap. The space
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allows any moisture in the oil to settle to the bottom of the
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cap - the capacitor will sit on these plexiglass supports above
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the moisture contaminated oil.
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PVC case:
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Cut three pieces of 6 inch diameter pvc pipe 19 inches long.
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Clean the pieces with alcohol. Prime ONE end of each pipe with
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pvc primer. Immediately swab bunches of pvc cement on this
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bottom 3 inches of each pipe. Swab the inside walls of three
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end caps which you prepared in the first step. IMMEDIATELY push
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an end cap onto the glue coated end of each of the three pipes.
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YOU WILL NOT GLUE A CAP ONTO THE TOP OF EACH PIPE YET - JUST THE
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BOTTOMS! As you push the bottom end caps on, twist them to help
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insure a good seal.
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Take the remaining three end caps which will be used for the
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TOPS of the capacitors. Using a saber saw cut a five inch
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diameter hole in the end of each cap. This will leave a 1/2 inch
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Page 5
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pvc border surrounding the hole. Cut three 6 inch diameter
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circles out of your 1/4 thick plexiglass stock.
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Next, we will score the TOP of the plexiglass with a sharp metal
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scribe in the shape if a big +, going from edge to edge. Below
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is a crude picture of these two cuts. Make the scribe marks at
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LEAST 1/32 inch deep.
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/===========\
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/\ \
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Cut two scribe / \ / \
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marks at right | \ / |
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angles to each | \ / | <-- TOP of plexiglass
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other. | / \ | capacitor cover
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\ / \ /
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\ / \/
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\========/
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*************** Important Safety Note *******************
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The purpose of the scribe marks is to provide starting
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places for CRACKS to occur should the capacitor fail and
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excess pressure occur. The plexiglass will bow outward
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and crack at the scribe marks, releasing pressure. MAKE
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SURE THAT THE SCRIBE MARKS ARE ON TOP WHEN YOU INSTALL
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THIS COVER!
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*********************************************************
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Use pvc cement and glue a 6 inch plexiglass disk over the
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hole you just cut in the end of the top cap. MAKE SURE
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THE SCRIBE MARKS ARE ON TOP! Do this for all three top
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end caps. You just created three TOP end caps with clear
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windows in the ends!
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*************** Safety Notes *************************
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The plexiglass will seal to the pvc, but pvc cement does
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not effectively bond plexiglass to pvc. This is good!
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Should the capacitor experience a pressure buildup due to
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electrical failure we WANT the plexiglass to crack and
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come loose and let the gasses out! The plexiglass cover
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also allows us to SEE a capacitor failure - the light
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from the arc shines out! The plexiglass cover serves as
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at least two important safety needs! Do NOT build a
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capacitor without this or some other form of over-
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pressure release mechanism!
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******************************************************
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*** Now let all pvc cement dry for 24 hours before doing
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any additional work on the pipes or end caps! See "PVC
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CONTINUED" below for completion of the TOP end caps
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after the glue has dried.
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Aluminum:
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Cut your aluminum flashing into six pieces, 14 inches
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wide (natural width) by 93 inches long. Use large
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scissors to make cuts. Cut all corners round (use a
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fifty cent piece to mark the curves on the corners) to
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reduce corona. Using a hand operated paper hole punch
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(any office supply has these), punch a hole in ONE end
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of EACH sheet, about 1/2 inch from the end, midway between
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Page 6
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the end corners. Take wet/dry sandpaper and sand all
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burrs and rough edges off the flashing. Preparation of
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the aluminum edges and corners is VERY important! Any
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burrs or roughness will result in capacitor failure!
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Attach a length of high voltage wire to the hole in the
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aluminum using a wire terminal and # 10 hardware. The
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wire should be about 16 inches long. Do not do anything
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with the other end of the wire yet. Cut your screw off
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as short as possible, very close to the nut. DO NOT GET
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METAL FILINGS OR METAL DUST ON YOUR ALUMINUM FLASHING OR
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POLY! METAL DEBRIS MEANS CAPACITOR DEATH!
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Poly sheet:
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Place sheets of newspaper on a carpeted foor. Put one of
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your poly sheets down on the newspaper and clean both
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sides with paper towels and alcohol. Measure a line 16
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inches from the edge. Take a magic marker and draw a
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line down the length of your sheet, 16 inches from the
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edge. Go to the opposite edge and do the same, drawing
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another line down the length of the sheet. Your poly
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sheet should now be marked into THREE equal pieces, each
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16" by 96". Using a box knife, carefully cut along these
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lines. You will have three pieces 16" by 96" long. When
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you complete these two cuts, carefully set the three
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pieces aside on a clean piece of paper. Next, clean,
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mark and cut your second piece of poly stock into three
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pieces. It is important that the poly you use is
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scratch-free and umblemished! Any imperfections can
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cause capacitor failure. You now have six 16" by 96"
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pieces of poly.
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Assembly:
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Place a 16" by 96" length of poly on your newspaper.
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Place one of your aluminum sheets on top of this first
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poly sheet. Align the aluminum so that you have an even
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1 inch border of poly showing all the way down it's 93
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inch length. Now scoot the aluminum towards the screw
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end so that the aluminum hangs over the END of the poly
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one inch.
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Note the 1 inch overlap of
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the aluminum end over poly! | |
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Top
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|--------------------------------------|
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| |=======================================
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Poly--->| | Aluminum sheet #1 O|<--hole and
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| | | screw for
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| | | wire
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| | |
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| |=======================================
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Left |--------------------------------------| Right
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Bottom
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Place poly sheet #2 on top of the first aluminum sheet.
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Align this poly exactly on top of the first poly sheet.'
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Page 7
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Place the final aluminum sheet on top of the second poly
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sheet. The screw end should be on the far end of the
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capacitor, OPPOSITE the first screw.
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| | Note the 1 inch overlap of the
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end of the aluminum over the poly!
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Top
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|--------------------------------------|
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|======================================= |
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| | |<- Poly sheet
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Hole & -> |O Aluminum sheet #2 | |
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screw | | | (poly and alum
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for wire | | | sheets #1
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| | | omitted
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|======================================= | for clarity)
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Left |--------------------------------------| Right
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Bottom
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You should have a capacitor sandwich consisting of, from the
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bottom of the stack up, poly, aluminum, poly, and aluminum. Make
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sure that the screws on the two sheets of aluminum are NOT ON THE
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SAME END OF THE CAPACITOR!
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Now carefully roll the capacitor up, starting on the left end.
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Make the core hole in the center of the roll about 2 inches
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across. Roll the capacitor up as TIGHT as possible! KEEP THE
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BORDERS ON EACH SIDE OF THE ALUMINUM STRAIGHT! If your aluminum
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gets too close to the edge of the capacitor, high voltage can arc
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around the edge of the poly, causing catastrophic failure. I
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really suggest getting a helper to help keep things lined up
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straight as you roll!
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Once the capacitor is rolled up, you should have a cylinder 16
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inches tall and about 4.5 to 5 inches in diameter. If your
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capacitor is much over 5 inches in diameter, then it won't fit
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inside the PVC pipe.
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Take three plastic tie-wrap straps and tie the rolled capacitor
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up so that it can't unroll. The two wires should come out of the
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top of the capacitor - one from the inside of the roll, one on
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the outside. Place a scrap piece of poly between the head of the
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screw and the underlying poly sheet so that the screw won't
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puncture the underlying poly sheet.
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PCV PREPERATION CONTINUED:
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Carefully slide your rolled capacitor into one of the pvc
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pipes, making sure the wires are "up". You should have
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about a 1/2 inch space between the outside of your capacitor
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and the inside wall of your pvc pipe. The capacitor will
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sit on the two plexiglass spacers which keep the capacitor
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1/2 inch above the bottom of the end cap (see step one).
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Take two of the split-bolt connectors and set them on top of
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the plexiglass window on the TOP end cap. The head of the
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bolt will sit on top of the plexiglass. Place the two bolts
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opposite each other, about 5 inches apart.
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Page 8
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/===========\
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Split bolt ----> / O \
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/ \ <-- 6 inch round cap with
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| | 5 inch plexi window
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| |
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| |
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\ /
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Split bolt ----> \ O /
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\========/
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Mark the plexiglass with a marker right around the edges of
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the bolt where it sits on the plexiglass. Next, clamp the
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bolt in a vise. Drill two holes through the head of the
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bolts. We will use two 1.5 inch long # 10 screws through
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these holes to attach the bolts to the plexiglass.
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Take the plexiglass window and prepare to drill holes in it.
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Place a drilled split-bolt on the plexiglass where we marked
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it earlier, and mark the new hole positions on the plexi.
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Drill the two holes. Coat the bottom of the split bolt with
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epoxy and attach the split-bolt connectors to the plexiglass
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window with 1.5 inch # 10 hardware as shown below. The
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epoxy is important to prevent oil leaks. Place epoxy on the
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screw threads where they pass through the split bolt and
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where they pass through the plexiglass:
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|| || <-- SPLIT BOLTS --> || ||
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|| || || ||
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|| === || || === ||
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====|==== < --- glop epoxy! -----> ====|====
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=======|=========================================|======<--plexi
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=======|=========================================|====== glass
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nuts ->=== ===
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| <-- SCREWS --> |
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| |
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Note: each split-bolt is held on with TWO sets of screws and nuts!
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Next, we drill and tap two holes in the plexiglass window for
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our two valves. Locate the holes for the valves as shown
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below:
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/===========\
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Split bolt ----> / O \
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/ \ <-- 6 inch round cap with
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| | 5 inch plexi window
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Valve holes --->| O O |
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| |
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\ /
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Split bolt ----> \ O /
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\========/
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This arrangement keeps the split-bolts far apart, and the
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two valves will be far enough away to prevent problems.
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The holes for the valves should be slightly smaller than
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the threaded portion of the valve. Be very careful tapping
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the plexiglass else it will split!
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Page 9
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Coat the threads of the threaded end of the valves with
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epoxy and screw the valves into the holes. The epoxy will
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seal the threads closed to the plexiglass and will prevent
|
|
oil leaks. Do not get epoxy inside the valve itself!
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|
Give the expoy a several minutes to dry. Hold the end cap
|
|
over the top of the capacitor. Test it to see how it fits
|
|
down over the 6 inch pvc pipe. Make sure the screws holding
|
|
the split-bolts do not come too close to the top of the
|
|
capacitor. Lift the end cap off the capacitor. The wire from
|
|
the inside of the capacitor will connect to a screw on one
|
|
split-bolt connector; the other wire from the outside of the
|
|
capacitor will connect to the OTHER split-bolt connector.
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Measure and cut the wires so that they are as short as
|
|
possible, YET STILL LONG ENOUGH TO REACH THE SCREWS HOLDING
|
|
THE SPLIT-BOLTS. Crimp and solder a round terminal connector
|
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on the end of the two capacitor wires. Attach each wire to
|
|
one of the split-bolts using another couple of #10 nuts and
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washers.
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|
Again, temporarily slide the top end cap on and check your
|
|
wires for fit. If all looks ok, it is time to glue this
|
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puppy on!
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First, open both vlaves so air can go through them. If you
|
|
forget this step, you won't be able to push the TOP down
|
|
over the pipe because of the trapped air!
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|
Slather the outside top three inches of your pvc pipe with
|
|
primer. Coat the inside walls of the end cap with primer
|
|
too. Next, coat over the primer with lots of pvc cement.
|
|
Quickly push the cap on the pipe, twisting back and forth
|
|
to make a good seal.
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|
|
Connect a vacuum pump to one of the valves with a length of
|
|
5/16 hose. While running the pump, apply additional glue
|
|
around the lip of the cap where it touches the pipe. Listen
|
|
for the hiss of air getting sucked in. If you find a leak,
|
|
add pvc cement until it stops. Now is the time to find and
|
|
fix any leaks! Once oil is introduced into the capacitor,
|
|
leaks cannot be sealed with cement - the oil will prevent
|
|
bonding!
|
|
|
|
Once you are satisfied the capacitor is leak-tight, let it
|
|
sit for at least 24 hours to allow the pvc cement to
|
|
completely dry. DO NOT PUT OIL IN A FRESHLY GLUED PIPE,
|
|
OR YOU WILL HAVE ONE HELL OF A MESS!
|
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|
|
After the glue has completely dried, test the end caps for
|
|
complete seal one more time. DO NOT TEST FOR LEAKS BY
|
|
PRESSURIZING THE PIPE! PRESSURIZING THE PIPE CAN RESULT IN
|
|
A VERY DANGEROUS EXPLOSION SHOULD THE PLASTIC FAIL!
|
|
|
|
Once you are satisfied the plastic-to-plastic seals are good
|
|
we can charge the capacitor with oil. The easiest way to do
|
|
this is to run a 5/16 inch rubber hose from one valve down
|
|
into the 5 gallon pail of oil. Attach your vacuum pump to
|
|
the other valve. The vacuum pump will produce a condition
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Page 10
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|
of reduced pressure in the capacitor, causing the oil to
|
|
flow up the hose from the pail through the second valve
|
|
into the capacitor!
|
|
|
|
WARNING: Do allow oil to enter the vacuum pump or permanent
|
|
damage to the pump can result!
|
|
|
|
Be sure to slowly open the oil valve - the oil will want to
|
|
foam up and enter the vacuum pump. Regulate the flow of
|
|
oil so that this does not happen. Stop the flow of oil
|
|
once the poly capacitor is under about 3/4 inch of oil.
|
|
|
|
Close the oil valve completely and let the vacuum pump suck
|
|
air out between the plates of the capacitor. Again, the
|
|
oil will want to foam up from all the entrapped air, so you
|
|
will have to monitor the vacuum valve very closely to
|
|
prevent oil from foaming up and entering the vacuum pump.
|
|
|
|
After a half hour or so, most of the air will be out of the
|
|
capacitor - at least enough where you can open the vacuum
|
|
valve so that the vacuum pump is going wide open. Be aware
|
|
that you will get air bubbles coming up out of the
|
|
capacitor even if you pump from now on 'til doomsday!
|
|
|
|
You will actually suck air THROUGH microscopic channels in the
|
|
pvc pipe and end caps! Your goal is to get as much air out
|
|
of the capacitor as is practicable - usually a couple of
|
|
hours of vacuum pumping will do the job.
|
|
|
|
After the capacitor has been thoroughly pumped down, shut off
|
|
the pump, disconnect the hoses. Slowly open one of the valves
|
|
and let air into the space above the capacitor to relieve the
|
|
vacuum. Close both valves on the capacitor to prevent
|
|
additional air and moisture from entering the capacitor.
|
|
|
|
Next comes the really hard part: set the capacitor aside
|
|
for at least one week, preferrable two weeks.
|
|
|
|
***********************************************************
|
|
DO NOT ATTEMPT TO USE THE CAPACITOR IMMEDIATELY AFTER
|
|
PUMPING IT DOWN! If you do, entrapped air will cause it to
|
|
fail. I have learned this the hard way! The capacitor
|
|
needs to sit for one to two weeks to allow air to rise out
|
|
of the capacitor.
|
|
***********************************************************
|
|
|
|
To break in your capacitor do the following:
|
|
|
|
Wait the required week or two weeks (see above).
|
|
|
|
Open one or both of the valves to act as additional
|
|
pressure relief ports in case the capacitor does fail.
|
|
|
|
************ Important Safety Note **********************
|
|
|
|
Set up the capacitor in a protected outdoor area. Make
|
|
sure kids, pets, nosey neighbors, etc. cannot get shocked
|
|
from the capacitor or test transformer. It is important
|
|
that the chosen test sight be outdoors because the capacitor
|
|
|
|
Page 11
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|
|
|
|
|
|
|
|
|
|
will be on high voltage for an extended period of time, and
|
|
you probably won't be around if the capacitor fails. If
|
|
the capacitor experiences a failure, and if power is not
|
|
IMMEDIATELY disconnected, there is a very real chance for
|
|
an oil fire! Better the fire burn a hole in your lawn than
|
|
your house or business to the ground!
|
|
**********************************************************
|
|
|
|
Attach a neon transformer controlled by a Variac (variable
|
|
115 volt transformer) to the capacitor. You may also use a
|
|
variable high voltage d.c. power supply. Slowly bring the
|
|
high voltage up to about 50% of the capacitor's rated
|
|
voltage. Let sit for eight hours. During this time, you
|
|
will see additional air bubble up out of the capacitor.
|
|
|
|
Air is a very real enemy! After this 8 hour time, slowly
|
|
bring the voltage up to 75% of the rated voltage. Let sit
|
|
another 8 hours. Finally bring up to rated voltage and let
|
|
sit for 30 minutes. If the capacitor is going to fail, it
|
|
will usually do so by this time.
|
|
|
|
Failure can result from poor quality or imperfect
|
|
polyethylene, insufficient poly thickness, burred aluminum
|
|
edges, oil containing moisture (1 part water in 10,000 parts
|
|
oil reduces the oil's insulation factor by 50% !!!) or
|
|
entrapped air. Insufficient border spacing around the
|
|
aluminum can also cause capacitor failure.
|
|
|
|
A properly constructed polyethylene capacitor will provide
|
|
very long service life at a very reasonable cost.
|
|
|
|
It is highly suggested that you open one of the valves on
|
|
the capacitor when using with a Tesla coil or other high
|
|
peak power source in case the capacitor should fail.
|
|
|
|
Having a valve open will vent a sudden build-up of pressure
|
|
from the gases which come from the vaporized plastic which
|
|
occurs when a capacitor fails. Close the valves whenever
|
|
the cap is NOT in use to prevent moisture in the air from
|
|
entering the capacitor.
|
|
|
|
The capacitor should be stored and transported standing
|
|
upright. If the capacitor gets turned on its side, the air
|
|
in the space above the capacitor will get back into the
|
|
layers of poly and aluminum - and you don't want to have to
|
|
go through the pump/wait process again!
|
|
|
|
Theoretically you could completely fill the capacitor with oil
|
|
- providing you left a way for the oil to expand and contract,
|
|
AND if you could build a 100% sealed PVC container. I assure
|
|
you that that is harder than one would suspect! The pvc end
|
|
caps may seep a tiny amount of oil THROUGH the plastic - pvc
|
|
is not nearly as non-permeable as we would be led to believe!
|
|
Keep the caps in a large pan to contain any oil leakage.
|
|
|
|
The pan should be large enough to contain all the oil stored
|
|
in one of the capacitors. The pan will contain leakage, and
|
|
should you have a capacitor container failure and oil fire,
|
|
the pan will contain the burning oil - definitely a plus!
|
|
|
|
Page 12
|
|
|
|
|
|
|
|
|
|
|
|
Again, remember one reason why we put a clear plexiglass
|
|
window on the top of the capacitor: it lets you see when
|
|
you have a capacitor failure! If the capacitor fails, the
|
|
high voltage arc will be visible through the clear window.
|
|
|
|
If you do have a capacitor failure, DISCONNECT POWER
|
|
IMMEDIATELY! FAILURE TO DISCONNECT POWER CAN RESULT IN A
|
|
CATASTROPHIC CAPACITOR FAILURE! DANGERS INCLUDE EXPLOSION
|
|
AND AN INTENSE OIL FIRE!
|
|
|
|
If you have questions concerning construction of these
|
|
capacitors, I may be reached through Keely Net. - Bert Pool
|
|
|
|
--------------------------------------------------------------------
|
|
|
|
If you have comments or other information relating to such topics
|
|
as this paper covers, please upload to KeelyNet or send to the
|
|
Vangard Sciences address as listed on the first page.
|
|
Thank you for your consideration, interest and support.
|
|
|
|
Jerry W. Decker.........Ron Barker...........Chuck Henderson
|
|
Vangard Sciences/KeelyNet
|
|
|
|
--------------------------------------------------------------------
|
|
If we can be of service, you may contact
|
|
Jerry at (214) 324-8741 or Ron at (214) 242-9346
|
|
--------------------------------------------------------------------
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Page 13
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