CATALOG NUMBER
081
LOCKE SUSPENSION
INSULATORS
BALTIMORE, MARYLAND
L O C K E
S U S P E N S I O N
I N S U L AT O R S
GUIDE TO SELECTION OF LOCKE SUSPENSION INSULATORS
Without Zinc Sleeve
(ANSI Class)
BA LL & S O C K ET T Y P E
With Zinc Sleeve
(ANSI Class)
Shed Diameter x Spacing
(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”)
M&E
Strength
C LEV I S T Y PE
Without Zinc Sleeve
Shed Diameter x Spacing
(ANSI Class)
(Leakage Distance)
*We offer 50,000 lb M&E insulators under NGK part numbers.
Please reference NGK catalog No. 14C.
1
LOCKE INSULATORS, INC. SUSPENSION INSULATORS
LOCKE SUSPENSION INSULATORS
Locke suspension insulators are designed and manu-
Today’s insulators
factured to give unparalleled performance and reliability.
provide even greater
the millions of units already in service. Although shapes
Silent testimony to this fact is the continuing function of
and appearances seem unchanging, today’s insulators
benefits and reliability
provide even greater benefits and reliability than in the
than in the past.
been added which significantly assist the transmission
past. Special features and performance capabilities have
line designer.
CONSTRUCTION DETAILS
1. CONNECTIONS
4. PORCELAIN SHELLS
Insulators are furnished with either ball-and-socket or
Proven manufacturing techniques provide the finest qual-
clevis-eye configurations. The ability for either style to
ity porcelain to ensure uniformly high mechanical and
be connected with other similar insulators is assured by
electrical strength.
conformance to ANSI standards. Routine checks are
made with gages.
Each class of insulator has been designed with the
unique configurations required to develop the required
electrical and mechanical performance.
2. COTTER KEYS
All exposed surfaces are glazed to provide a smooth
hard finish, which is easily cleaned of contaminants, and
Positive locking of both types is attained by using a
which significantly enhances the mechanical strength.
humped-type cotter key to prevent unintentional uncoupling during service or handling.
Glaze-bonded sand surfaces on the porcelain provide
reliable gripping areas for the cement to develop the full
The ball-and-socket design has enjoyed a greater popu-
strength of the insulator.
larity over the years because of the overall flexibility and
the lack of loose parts. The self-contained split cotter
key, by virtue of its hump, can be maintained in either
5. ASSEMBLY & TEST
the locked or unlocked position.
Assembly of hardware and porcelain is made with
Alumina cement, which has superior characteristics over
3. CAPS & PINS
the Portland cement which is normally used. The cement
is steam-cured under controlled conditions to achieve
Caps are manufactured of malleable iron or ductile iron.
Pins are forged steel.
Caps and pins are galvanized per ASTM A153.
optimum physical properties.
Each insulator is mechanically proof-tested at 50% of its
M&E rating and is electrically tested prior to shipment.
A permanently flexible coating on the inside of the cap
and on the pin protects the cap and pin from chemical
6. MARKING & COLOR
attack by the cement. The coating also provides more
uniform distribution of working stresses in the insulator
Each porcelain shell is permanently marked to show the
components.
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.
3
LONG TERM STRENGTH
LOKGARD SLEEVE
Experience shows that Locke suspension insulators
All Locke ball and socket suspension insulators can be
maintain their mechanical strength over long periods of
equipped with Lokgard sleeves where pin corrosion has
time without deterioration. This performance results
been or is expected to be a problem. Serious pin
from using properly engineered materials, good design,
corrosion can result from electrolytic action with the
and modern manufacturing equipment and technology.
most severe activity apparently related to areas having
We think that it is important to be able to substantiate
high levels of contamination. Corrosion can take place
that our insulators do indeed have long-term strength.
totally outside of the cement which results solely in loss
®
of pin cross-section and hence mechanical strength.
We have established an in-house specification to use the
Or it can take place inside the cement causing bursting
IEC Publication 60575, “Thermal-Mechanical Perfor-
pressure to the porcelain shell with subsequent
mance Test and Mechanical Performance Test on String
catastrophic electrical and mechanical failure.
Insulator Units”, as a design test for all Locke suspension insulators. This test consists of simultaneously
The Lokgard sleeve is high purity zinc that is cast on to
applying a mechanical cyclical load and a thermal cyclical
the insulator pin prior to assembly. It too will corrode
environment to the insulators. After four cycles, the
in service at approximately the same rate as the steel
insulators are subjected to an M&E test. We feel that
in the pin, but until the zinc is consumed, no corrosion
the M&E results obtained after cyclical stressing of the
of the steel can occur. Additionally, the zinc oxidizes
insulators should be substantially the same as the M&E
without residue, and cannot build up the larger expansion
results obtained without cyclical testing.
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.
A substantial amount of data obtained on a variety of
designs by many manufacturers shows a remarkable correlation with extended field performance Designs that
perform well on this test have performed very well in
service whereas those designs that perform poorly have
demonstrated generally unsatisfactory field performance.
Contact your local sales representative for design reports
covering Long-Term Tests.
4
20,000 lb. M & E
CHARACTERISTICS
Catalog Number
Cat. No. w/LOKGARD Sleeve
ANSI Class
M&E Rating, lb.
Leakage Distance in.
Dry Arcing Distance, in.
Mechanical Impact Strength, in.-lb.
Tension Proof, lb.
Dry, kV
Low Frequency Flashover
Wet, kV
Pos., kV
Critical Impulse Flashover
Neg., kV
Low Frequency Puncture, kV
“Test Voltage,
“Radio influence
RMS to Ground, kV”
Voltage Data”
“Max. RIV
at 1000 kHz, uV “
Net Weight Each, lb.
Standard Package Quantity
Packed Weight, lb.
20S840
ANSI CLASS 52-3
20S840
20S195
52-3
20,000
12 5/8
7 9/16
100
10,000
80
50
125
130
110
20S580
52-4
20,000
12 5/8
7 9/16
100
10,000
80
50
125
130
110
10
10
50
50
10.6
6
78
12.1
6
82
20S580
ANSI CLASS 52-4
5
30,000 lb. M & E
CHARACTERISTICS
Catalog Number
Cat. No. w/LOKGARD Sleeve
ANSI Class
M&E Rating, lb.
Leakage Distance in.
Dry Arcing Distance, in.
Mechanical Impact Strength, in.-lb.
Tension Proof, lb.
Dry, kV
Low Frequency Flashover
Wet, kV
Pos., kV
Critical Impulse Flashover
Neg., kV
Low Frequency Puncture, kV
“Test Voltage,
“Radio influence
RMS to Ground, kV”
Voltage Data”
“Max. RIV
at 1000 kHz, uV “
Net Weight Each, lb.
Standard Package Quantity
Packed Weight, lb.
30S255
ANSI CLASS 52-5
6
30S255
30S295
52-5
30,000
12 5/8
7 9/16
100
15,000
80
50
125
130
110
30S257
52-6
30,000
12 5/8
7 9/16
100
15,000
80
50
125
130
110
10
10
50
50
11.7
6
84
12.1
6
82
30S257
ANSI CLASS 52-6
40,000 lb. M & E
CHARACTERISTICS
Catalog Number
Cat. No. w/LOKGARD Sleeve
ANSI Class
M&E Rating, lb.
Leakage Distance in.
Dry Arcing Distance, in.
Mechanical Impact Strength, in.-lb.
Tension Proof, lb.
Dry, kV
Low Frequency Flashover
Wet, kV
Pos., kV
Critical Impulse Flashover
Neg., kV
Low Frequency Puncture, kV
“Test Voltage,
“Radio influence
RMS to Ground, kV”
Voltage Data”
“Max. RIV
at 1000 kHz, uV “
Net Weight Each, lb.
Standard Package Quantity
Packed Weight, lb.
40S360
ANSI CLASS 52-8
40S360
40S370
52-8
40,000
12 13/16
7 11/16
100
20,000
80
50
125
130
110
40S290
52-10
40,000
12 13/16
7 11/16
100
20,000
80
50
125
130
110
10
10
50
50
14.7
6
97
15.4
6
102
40S290
ANSI CLASS 52-10
7
8
10” x 6 1/2”
10” x 5 3/4”
Disc Dia.
x Spacing
715
735
Critical
Impulse
Flashover kv Negative 640
315
490
625
270
Low
Frequency
Flashover kv Wet
Positive
425
Dry
660
Critical
Impulse
Flashover kv Negative 575
280
640
240
Low
Frequency
Flashover kv Wet
440
7
560
380
Dry
Positive
6
Number of Units
830
805
365
550
745
720
320
495
8
925
895
410
610
825
800
360
545
9
520
745
13
560
795
14
600
840
15
640
880
16
680
925
17
720
965
18
20
21
22
23
24
25
26
27
28
29
30
760
805
845
885
925
965
1005 1045 1085 1125 1165 1205
1005 1045 1080 1120 1155 1190 1220 1255 1285 1320 1350 1380
19
545
775
590
825
635
875
680
920
725
970
770
815
860
905
950 1000 1045 1090 1135 1180 1225 1270 1315 1360
1015 1055 1100 1140 1180 1215 1255 1290 1325 1360 1395 1425 1460 1490
1080 1165 1250 1335 1420 1505 1590 1675 1760 1845 1925 2010 2095 2180 2265 2350 2435 2520 2605
1040 1120 1200 1280 1360 1440 1520 1600 1680 1760 1835 1915 1995 2075 2155 2235 2315 2395 2475
480
700
12
1075 1165 1255 1345 1435 1525 1615 1705 1795 1885 1975 2065 2155 2245 2335 2425 2515 2605 2695 2785
500
720
995
960
440
650
11
1020 1120 1215 1310 1405 1500 1595 1690 1785 1885 1980 2075 2170 2265 2360 2455 2550 2650 2745 2840 2935
985
455
665
910
880
400
600
10
STRING FLASHOVER CHARACTERISTICS (Based on ANSI 29-1 Test Procedures)
S A L E S
O F F I C E S
NGK-LOCKE INC. (BALTIMORE OFFICE)
2525 Insulator Drive
Baltimore, Maryland 21230, U.S.A.
Tel: +1(410) 347-1700
Fax: +1(410)347-1724
Email: NLBALT@ngkus.com
NGK-LOCKE INC. (ATLANTA OFFICE)
1880 West Oak Parkway
Suite 104
Marietta, Georgia 30062, U.S.A.
Tel: +1(404) 659-3153
Fax: +1(678) 303-1374
Email: NLATL@ngkus.com
NGK-LOCKE INC. (DALLAS OFFICE)
1452 Hughes Road
Suite 200
Grapevine, Texas 76051, U.S.A.
Tel:+1(817) 410-5789
Fax:+1(817) 796-2290
Email: NLDA@ngkus.com
NGK-LOCKE INC. (LOS ANGELES OFFICE)
21250 Hawthorne Blvd., Suite 500
Torrance, California 90503, U.S.A.
Tel: +1(310) 316-3323
Fax: +1(310)316-3944
Email: NLLA@ngkus.com
NGK INSULATORS OF CANADA, LTD.
(TORONTO OFFICE)
2700 Matheson Blvd. East, Suite 700
East Tower, Mississauga, Ontario L4W 4V9, Canada
Tel: +1(905) 602-1266
Fax: +1(905)238-8247
Email: NCTOR@ngkus.com
NGK INSULATORS OF CANADA, LTD.
(MONTREAL OFFICE)
1501, Avenue McGill College, Bureau 515
Montreal (Quebec) H3A 3M8, Canada
Tel: +1(514) 281-8488
Fax: +1(514)281-8596
Email: NCMON@ngkus.com
BALTIMORE, MARYLAND