GE Gerapid 2607 User Manual page 6

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3.2.3 Mechanism
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The Gerapid is equipped with a modular designed
mechanism, which is wear-resistant and nearly mainte-
nance-free. This mechanism ensures an extended electri-
cal and mechanical endurance of the breaker as well as a
high level of safety under all operation conditions.
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Breaker c an operate 20 000 cycles when opened by the
shunt trip or zero voltage release, and 1 000 operations
by means of ED impulse coil or OCT releases.
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This mechanism is mechanic ally latc hed in the CLOSED
position. The principle of a mechanically latc hed mecha-
nism offers a big advantage compared to often used
electro magnet holding system. No auxiliary control
power source is required to keep breaker closed.
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The mechanism is provided with two tripping latches [Fig.
6]. First latch, c alled "slow latch", is used f or opening un-
der normal conditions, like actuation of shunt trip or zero-
voltage release. The second one, "quick latc h", de-
clutches the main contact arm from the mechanism and
opens the c ontacts with an extremely short delay. This is
used when interrupting short-circ uit or overloads. All
safety releases operate onto "quick latch" latch.
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Different main springs are used in mechanisms for differ-
ent breaker f rames. Therefore mec hanisms cannot be
exchange between breakers of different frame.
Fig. 6 Latching and tripping system
3.2.4 Over-Current Tripping release (Code 7)
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The OCT release is a magnet with two magnetic circ uits,
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 con-
trol voltage to operate.
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The OCT consists of the holding circuit [6], the mov able
armature [3] and the tripping circ uit [7]. The holding and
the tripping magnetic circ uits are both excited by load
current [1]. Until the static overload release's response
threshold has been reac hed, the armature [3] is held in
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Design and specifications are subject to change without notice
position by the holding flux (ΦH) [2] and the c ounter
spring's force [4]. Once the load c urrent exceeds the set
static response threshold, the attraction flux (ΦA) [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.
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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.
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When supplied with the optional transparent side protec-
tion c overs (Code 15), a fixed mounted insulated knob is
provided to enable OCT adjustment [Fig. 16].
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Fig. 7 OCT device.
Default tripping bands for the OC release
No
OCT band 2607 4207 6007 8007
1 1,5 kA - 2,5 kA
2 1,5 kA – 3 kA
3 1,5 kA – 4 kA
4 1,5 kA – 5 kA
5 2 kA – 6 kA
6 2 kA – 7 kA
7 2 kA – 8 kA
8 2,5 kA - 5,5 kA
9 3 kA – 7 kA
10 3 kA – 8 kA
11 3 kA – 9 kA
12 3 kA – 12 kA
13 5 kA – 10 kA
14 6 kA – 14 kA
15 7 kA – 15 kA
16 8 kA – 18 kA
17 10 kA – 16 kA
18 12 kA – 24 kA
1) Customer specific bands on request.
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1)
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S47183e rev.03 2009-09-02