90007 tecnologia de corte laser

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The extended foil solderless EXcapacitor introduced in 1986 by McGraw-Edison revolutionalized capacitor dielectricechnology and manufacturing methodsand created the foundation for further

major advancements. Next came the EX-7with the high stacking factor that resultedn lower dielectric losses and higher sys-em efficiency.

Now, as Cooper Power Systems, wecontinue to make history with the EX-7L,latest in a long, proud line of trendsetting

accomplishments:

1946Individual capacitor impregnation

1955

50- and 100-kvar capacitors1959

230-kV shunt-capacitor bank

1968Environmentally controlled clean room

for pack winding

1971All film dielectric

1975Non-PCB dielectric fluid

1977Complete conversion to all-film/

non-PCB production

1979300-kvar 1 capacitor NEMA-standard mounting centers

1981400-kvar 1 capacitor with NEMA-

standard mounting centers

1983500-kV/750-Mvar, metal-oxide-protected

series-capacitor bank

1986EX extended-foil/solderless capacitor

1987EX-7 high-stacking-factor capacitor with

Edisol XT dielectric fluid

1988Unified and definite tank rupturecurve up to 10 kA

9300-parallel kvar per series groupcapability in conjunction with

expulsion fuses

1990EX-7L capacitor using laser-cut foil

More than 40 years of progressthrough innovation.

ver the pasttwenty years,

three majorbreakthroughs have taken place incapacitor technology:

1. The elimination of paperdielectrics with the development

of the all-film capacitor;2. The development of non-PCB

dielectric fluids;3. The development of extendedfoil, mechanically crimped

capacitor pack construction.All of these developments were the

proud result of Cooper PowerSystems drive to do it better through

research and development. Now, withthe McGraw-Edison Type EX-7L capaci-

tor, we bring you a major technologicalbreakthroughlaser-cut foil that con-trols the electric field in the capacitor

dielectric system.

Laser Cut FoilThe Manufacturing Edge

Applying laser technology, CooperPower Systems has literally re-shaped

the foil edge in the EX-7L capacitor,and thereby reduced foil edge

electrical stress levels, substantiallyenhancing capacitor performance.

The new EX-7L dielectric

system uses foil that is slit by a laserbeam,replacing the mechanically

slit foil used in conventional powercapacitors.

Figure 1 is a micrograph of the fedge produced by conventional

mechanical slitting procedures. Youwill note the rough, non-uniformsurface of the foil edge, which is

where corona occurs.Figure 2 illustrates the consisten

rounded edge achieved through thelaser-cutting process. The round ed

significantly reduces dielectric stresat the foil edge, the critical point in t

capacitors dielectric system.Figure 3 shows the advancedlaser equipment used to slit the foil.

This foil manufacturing break-througmelts the foilinstead of tearing

itduring the slitting process, result

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ing in consistently rounded edges. Theuse of this foil significantly increases

the Discharge Inception Voltage (DIV)levels of the capacitor and endowsthe EX-7L with unprecedented perfor-

mance capabilities.

Reduced Electric

Field StressThe Technological Edge

Corona, often referred to as discharge,

occurs in a capacitor when theelectrical field stress exceeds the

dielectric strength of the fluid at thefoil edge. Discharge conditions are the

primary cause of premature capacitorwearout.

Figure 4 plots the electrical field at

the edge of mechanically slit foil. Thecloser the field lines, the higher the

edge stress.Figure 5 shows how the laser cut

foil edge reshapes the electrical field,thereby reducing stress. The lowered

edge stress levels result in a substan-tial increase in the voltage at whicha capacitor begins to go into corona.

This is what gives the Type EX-7L itsoutstanding performance.

Figure 6 illustrates the dramaticimprovement in the DIV performance

of the Type EX-7L capacitor over thatof a similar design using mechanicallyslit foil.

The EX-7L EdgeMatching ProductInnovation withManufacturingTechnology

The McGraw-Edison Type EX-7Lcapacitor combines all four mate-

rial advancements introduced to thepower capacitor industry by Cooper

Power Systems: All film dielectrics

Non-PCB dielectric fluids Mechanically crimped extended-foil

high-energy construction(No Solder!)

Laser-cut aluminum foil.

Again, Cooper Power Systemsmatches product innovation with high-

technology manufacturing. The resultis a capacitor thats unsurpassed in

the world for performanceperfor-mance you can count on down theline.

Unique Dielectric

Systems,

World Class

Manufacturing,

And Much,

Much More

Figure 4 Plot of the electrical field

around the foil edge of mechanicallyslit foil. Note the concentration of

stress at the foil edge. Figure 5 Plot of the electrical fieldaround the foil edge of laser-cut foil.

Note how the smooth foil edgereduces stress buildup.

The EX-7L capacitorincorporates the best

features of our field provenEX and EX-7 designs: Extended Foil Solderless Construction

All Film Solid Dielectric 10-kA Fault Current

Handling Capability

9300-kvar Parallel Energy

Capability Low 0.07 Watts per kvar*Losses

* AT 60 hZ

Give your system the

Edge with the EX-7L.


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2005 Cooper Power Systems or its affiliates 1045 Hickory Street

Bulletin 90007 February 2005 Supersedes February 1990 Pewaukee, WI 53072 USAwww.cooperpower.com

90007 tecnologia de corte laser

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