GE Industrial Solutions GERAPID 2508, 4008, 5008, 6008 WITH ARC CHUTE 1X2 - Manual (Page 6)

6 Design and specifications are subject to change without notice S47183De rev.02 2011-03-14
3.2.3 Mechanism
 The Gerapid is equipped with a modular designed
mechanism, which is wear-resistant and nearly maintenance-
free. This mechanism ensures an extended electrical and
mechanical endurance of the breaker as well as a high level
of safety under all operation conditions.
 Breaker can operate 20 000 cycles without maintenance
when opened by the shunt trip or zero voltage release coils,
and 1 000 operations by means of impulse coil or OCT
releases.
 This mechanism is mechanically latched in the CLOSED
position. A mechanically latched mechanism offers
advantage compared to often used electro magnet holding
system. No auxiliary control power source is required to keep
breaker closed.
 The mechanism is provided with two tripping latches [Fig. 6].
One latch, called “slow latch”, is used for opening under
normal conditions, like actuation of shunt trip or zero-voltage
release. The second one, “quick latch”, de-clutches the main
contact arm from the mechanism and opens the contacts
with an extremely short delay. This is used when interrupting
short-circuit or overloads. All safety releases operate onto
“quick latch”.
 Different main springs are used in mechanisms for different
breaker frames. Therefore mechanisms cannot be exchanged
between breakers of different frame.
Fig. 6 Latching and tripping system
3.2.4 Overcurrent release OCT
 The OCT release is a magnet with two magnetic circuits,
optimizing the twin magnetic field principle [Fig. 7]. This
technology ensures equally fast tripping in both current
directions. This system does not require an auxiliary control
voltage to operate. It is a direct acting and instantaneous
tripping device.
 The OCT consists of the holding circuit [6], the movable
armature [3] and the tripping circuit [7]. The holding and the
tripping magnetic circuits are both excited by load current [1].
Until the static overload release’s response threshold has
been reached, the armature [3] is held in position by the
holding flux (H) [2] and the counter spring’s force [4]. Once
the load current exceeds the set static response threshold,
the attraction flux (A) [2] takes over and rapidly pulls down
 the flexible armature [3]. During this operation, the armature
hits the seesaw, which releases the quick latch in the
mechanism. The latch and contacts are opened immediately.
 The OCT is available in either a fixed setting or adjustable over
specific ranges. On the adjustable OCT, the response
threshold can be easily adjusted by turning the adjustment
nut with a SW6 hexagon wrench. The available ranges are
described in the table below. Other ranges might be possible
on request.
Fig. 7 OCT device.
Default tripping bands for the OCT release 1) .
1) Customer specific bands on request.
Code OCT bands 2508 4008 5008 6008
A 1.5 kA – 2.5 kA
B 1.5 kA – 3 kA
C 1.5 kA – 4 kA
D 1.5 kA – 5 kA
E 2 kA – 6 kA
F 2 kA – 7 kA
G 2 kA – 8 kA
H 2,5 kA - 5,5 kA
J 3 kA – 7 kA
K 3 kA – 8 kA
L 3 kA – 9 kA
M 3 kA – 12 kA
N 5 kA – 10 kA
P 6 kA – 14 kA
Q 7 kA – 15 kA
S 8 kA – 18 kA
T 10 kA – 16 kA
U 12 kA – 24 kA
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