GE Industrial Solutions EntelliGuard R AKD-6 - Manual (Page 9)

8 EntelliGuard R Circuit Breaker Retrofill AKD-6 Installation Manual DEH-41548 02/12
History and Types
AKD
AK—Power Circuit Breaker Equipment
D—Drawout circuit breaker construction
Manufactured from 1951 to 1975 were these: all bolted, copper bus design, all drawout breakers—AK-1, —2, —3,—
15 / 25 / 50 / 75 / 100; the 4000A-max bus rating, 4 levels of bus, ring-bus used in all feeder sections, and the main
bus with provisions for future extension; sections in outdoor construction, which did not line up in the front; and
indoor construction, with extended frames allowing the section fronts to line up. Moreover, there were indoor
depths 49" (225 / 600A breakers), 59" (1600A breakers), and 63" (3200 / 4000-A breakers).
Back then, breakers had a ratcheting drawout mechanism, with an open-door drawout. Breakers were painted
ANSI 61, light gray, manufactured in Philadelphia from 1951 to the mid-60s and in Burlington from the mid-60s
to 1975.
The breaker compartment was a welded assembly, and the equipment frame was bolted. Breaker boxes were
stacked to make a vertical section with equipment frame around the breaker boxes. There were no bus
compartment barriers, just an open bus design. Ring silver-plating was applied to bolted connections.
AKD-6—AKR30H/AKR30L/AKR50H
The AKD-6 was manufactured in Salisbury, NC from 1977 to 1981. Some AKD-5s, which were built in Salisbury from
1975 until 1977, got name-plated as AKD-6. There is no “flash-butt” welded aluminum to copper. Aluminum bus is
tin-plated and bolted at shipping splits (but welded everywhere else). Copper bus design has ring silver plating at
bolted joints. AKR-75 / 100s were introduced during this time. Stab-and-finger connections on 3200A and 4000A
breakers were improvements, versus the round the primary disconnects located on the AKD-5s.
The AKD-6 uses inner-house drawout breaker compartments and tuning fork primary disconnects (extrusions) on
the 800—2000A breaker compartments. They have copper feeder breaker runbacks and 60"-deep frames with 18"-
optional rear extensions. They are painted ANSI 61 light gray and breakers have ECS or SST trip units.