locke suspension insulators

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LOCKE SUSPENSIONLOCKE SUSPENSIONINSULATORSINSULATORS

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GUIDE TO SELECTION OF LOCKE SUSPENSION INSULATORS

B A L L & S O C K E T T Y P E C L E V I S T Y P E M&E Without Zinc Sleeve With Zinc Sleeve Shed Diameter x Spacing Without Zinc Sleeve Shed Diameter x Spacing

Strength (ANSI Class) (ANSI Class) (Leakage Distance) (ANSI Class) (Leakage Distance)

20K 20S840 (52-3) 20S195 (52-3) 10” x 5 3/4”(12 5/8”) 20S580 (52-4) 10” x 5 3/4”(12 5/8”)

30K 30S255 (52-5) 30S295 (52-5) 10” x 5 3/4” (12 5/8”) 30S257 (52-6) 10” x 5 3/4” (12 5/8”)

40K 40S360 (52-8) 40S370 (52-8) 10” x 5 3/4” (12 13/16”) 40S290 (52-10) 10” x 6 1/2” (12 13/16”)

50K --- CA589MZ* (52-11) 11” x 6 1/8” (15 15/16”) CA589Q* (52-12) 11” x 7” (15 15/16”)

*We offer 50,000 lb M&E insulators under NGK part numbers. Please reference NGK catalog No. 14C.

L O C K E S U S P E N S I O N I N S U L A T O R SL O C K E S U S P E N S I O N I N S U L A T O R S

LOCKE INSULATORS, INC. SUSPENSION INSULATORS

Locke suspension insulators are designed and manu-

factured to give unparalleled performance and reliability.

Silent testimony to this fact is the continuing function of

the millions of units already in service. Although shapes

and appearances seem unchanging, today’s insulators

provide even greater benefi ts and reliability than in the

past. Special features and performance capabilities have

been added which signifi cantly assist the transmission

line designer.

LOCKE SUSPENSION INSULATORS

CONSTRUCTION DETAILS

Today’s insulators

provide even greater

benefi ts and reliability

than in the past.

3

1. CONNECTIONS

Insulators are furnished with either ball-and-socket or

clevis-eye confi gurations. The ability for either style to

be connected with other similar insulators is assured by

conformance to ANSI standards. Routine checks are

made with gages.

2. COTTER KEYS

Positive locking of both types is attained by using a

humped-type cotter key to prevent unintentional uncou-

pling during service or handling.

The ball-and-socket design has enjoyed a greater popu-

larity over the years because of the overall fl exibility and

the lack of loose parts. The self-contained split cotter

key, by virtue of its hump, can be maintained in either

the locked or unlocked position.

3. CAPS & PINS

Caps are manufactured of malleable iron or ductile iron.

Pins are forged steel.

Caps and pins are galvanized per ASTM A153.

A permanently fl exible coating on the inside of the cap

and on the pin protects the cap and pin from chemical

attack by the cement. The coating also provides more

uniform distribution of working stresses in the insulator

components.

4. PORCELAIN SHELLS

Proven manufacturing techniques provide the fi nest qual-

ity porcelain to ensure uniformly high mechanical and

electrical strength.

Each class of insulator has been designed with the

unique confi gurations required to develop the required

electrical and mechanical performance.

All exposed surfaces are glazed to provide a smooth

hard fi nish, which is easily cleaned of contaminants, and

which signifi cantly enhances the mechanical strength.

Glaze-bonded sand surfaces on the porcelain provide

reliable gripping areas for the cement to develop the full

strength of the insulator.

5. ASSEMBLY & TEST

Assembly of hardware and porcelain is made with

Alumina cement, which has superior characteristics over

the Portland cement which is normally used. The cement

is steam-cured under controlled conditions to achieve

optimum physical properties.

Each insulator is mechanically proof-tested at 50% of its

M&E rating and is electrically tested prior to shipment.

6. MARKING & COLOR

Each porcelain shell is permanently marked to show the

manufacturer name, year of manufacture, M&E Strength

and Proof-Test Value which has been applied to the

insulator.

Insulators are available in the following glaze colors: light

gray, dark gray, royal blue, and brown.

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LONG TERM STRENGTH

Experience shows that Locke suspension insulators

maintain their mechanical strength over long periods of

time without deterioration. This performance results

from using properly engineered materials, good design,

and modern manufacturing equipment and technology.

We think that it is important to be able to substantiate

that our insulators do indeed have long-term strength.

We have established an in-house specifi cation to use the

IEC Publication 60575, “Thermal-Mechanical Perfor-

mance Test and Mechanical Performance Test on String

Insulator Units”, as a design test for all Locke suspen-

sion insulators. This test consists of simultaneously

applying a mechanical cyclical load and a thermal cyclical

environment to the insulators. After four cycles, the

insulators are subjected to an M&E test. We feel that

the M&E results obtained after cyclical stressing of the

insulators should be substantially the same as the M&E

results obtained without cyclical testing.

A substantial amount of data obtained on a variety of

designs by many manufacturers shows a remarkable cor-

relation with extended fi eld performance Designs that

perform well on this test have performed very well in

service whereas those designs that perform poorly have

demonstrated generally unsatisfactory fi eld performance.

Contact your local sales representative for design reports

covering Long-Term Tests.

LOKGARD® SLEEVE

All Locke ball and socket suspension insulators can be

equipped with Lokgard sleeves where pin corrosion has

been or is expected to be a problem. Serious pin

corrosion can result from electrolytic action with the

most severe activity apparently related to areas having

high levels of contamination. Corrosion can take place

totally outside of the cement which results solely in loss

of pin cross-section and hence mechanical strength.

Or it can take place inside the cement causing bursting

pressure to the porcelain shell with subsequent

catastrophic electrical and mechanical failure.

The Lokgard sleeve is high purity zinc that is cast on to

the insulator pin prior to assembly. It too will corrode

in service at approximately the same rate as the steel

in the pin, but until the zinc is consumed, no corrosion

of the steel can occur. Additionally, the zinc oxidizes

without residue, and cannot build up the larger expansion

volume in the manner of rusted steel. Therefore, it is

impossible for a Lokgard protected insulator porcelain

shell to be subjected to corrosion-caused hoop

stress damage.

20,000 lb. M & E

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Catalog Number 20S840 20S580Cat. No. w/LOKGARD Sleeve 20S195 -ANSI Class 52-3 52-4

M&E Rating, lb. 20,000 20,000Leakage Distance in. 12 5/8 12 5/8Dry Arcing Distance, in. 7 9/16 7 9/16Mechanical Impact Strength, in.-lb. 100 100Tension Proof, lb. 10,000 10,000

Low Frequency Flashover Dry, kV 80 80

Wet, kV 50 50

Critical Impulse Flashover Pos., kV 125 125

Neg., kV 130 130Low Frequency Puncture, kV 110 110

“Test Voltage,

10 10 RMS to Ground, kV” “Max. RIV

50 50 at 1000 kHz, uV “

Net Weight Each, lb. 10.6 12.1Standard Package Quantity 6 6Packed Weight, lb. 78 82

“Radio infl uenceVoltage Data”

CHARACTERISTICS

20S840ANSI CLASS 52-3


30,000 lb. M & E

6




Wet, kV 50 50



“Test Voltage,


50 50 at 1000 kHz, uV “



CHARACTERISTICS



40,000 lb. M & E

7




Wet, kV 50 50



“Test Voltage,


50 50 at 1000 kHz, uV “



CHARACTERISTICS



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BALTIMORE, MARYLAND

S A L E S O F F I C E S

NGK-LOCKE INC. (BALTIMORE OFFICE)

2525 Insulator DriveBaltimore, Maryland 21230, U.S.A.

Tel: +1(410) 347-1700Fax: +1(410)347-1724

Email: [email protected]

NGK-LOCKE INC. (ATLANTA OFFICE)

1880 West Oak ParkwaySuite 104

Marietta, Georgia 30062, U.S.A.Tel: +1(404) 659-3153Fax: +1(678) 303-1374


NGK-LOCKE INC. (DALLAS OFFICE)

1452 Hughes RoadSuite 200

Grapevine, Texas 76051, U.S.A.Tel:+1(817) 410-5789 Fax:+1(817) 796-2290


NGK-LOCKE INC. (LOS ANGELES OFFICE)

21250 Hawthorne Blvd., Suite 500Torrance, California 90503, U.S.A.

Tel: +1(310) 316-3323 Fax: +1(310)316-3944


NGK INSULATORS OF CANADA, LTD.

(TORONTO OFFICE)

2700 Matheson Blvd. East, Suite 700East Tower, Mississauga, Ontario L4W 4V9, Canada

Tel: +1(905) 602-1266Fax: +1(905)238-8247


NGK INSULATORS OF CANADA, LTD.

(MONTREAL OFFICE)

1501, Avenue McGill College, Bureau 515Montreal (Quebec) H3A 3M8, Canada

Tel: +1(514) 281-8488 Fax: +1(514)281-8596


locke suspension insulators

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