GE Industrial Solutions EntelliGuard R AKD-5 - Manual (Page 10)

9 EntelliGuard R Circuit Breaker Retrofill AKD-5 Installation Manual DEH-41547 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 / 4000A 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-5—AK25/AK50
Manufactured from 1960 until 1977, the aluminum bus had copper that was “flash-butt welded” to the
aluminum at bolted connections. During that time, AK-2A, 3A -25 / 50 / T50 / 75 / 100 (“A” signifies AKD-
5 drawout) were produced. Pull-lanyard drawout mechanism on early design was replaced by a single
jackscrew mechanism and then later replaced by a double jack-screw mechanism. Featured is a closed-
door, drawout with inner house breaker compartment. There is a 60"-deep frame with the 18"-extension
option. Outdoor protected aisle uses 60"-deep indoor frame. Two bus levels are available with a ring bus
used at 4000A. Particulars include: welded/riveted frame, bus compartment barriers, line/load
separation barriers on mains and ties, isolation barriers on transformer transitions, copper runbacks on
feeder breakers, ring silver-plating on copper, and aluminum bus un-plated (welded connections). The
switchgear is painted sand-gray (beige), with some instrument doors painted blue. AKR-30/50 in 22"-
wide sections were introduced in AKD-5 construction, early 70s. AK25s and AK50s were also available
as substructure kits for OEMs to build around customer gear.
Unpack Retrofill Circuit Breaker
By following the procedures below, you should be able to install the breaker with minimum effort
and time.