GE Industrial Solutions EntelliGuard 800–2000 A Frames, 240–600 Vac Maintenance Manual - Manual (Page 13)

EntelliGuard™ 800–2000 A Power Circuit Breakers
Chapter 2. Description
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2.1 Introduction
EntelliGuard low-voltage power circuit breakers control
and protect power circuits up to 600 volts. They will safely
switch loads and automatically clear circuits during abnor-
mal conditions when used with the EntelliGuard
Messenger™. These include short circuits, sustained
overloads, and ground faults.
EntelliGuard breakers contain a “quick-make, quick-
break” mechanism, which stores energy in a closing spring
for quick release. During closing, some energy is
transferred to an opening spring to be used subsequently
for fast tripping.
The three main functional components of the breaker are
its mechanism, an assembly consisting of the conductive
components, and the interrupter.
The mechanism is designed to receive energy, store it, and
later deliver it to close the breaker contacts. It must be able
to reverse the closing operation at any point upon receipt
of a trip signal from the EntelliGuard Messenger (that is,
it must be “trip-free”). Finally, it must also open a closed
breaker quickly enough to minimize contact erosion and
to effectively transfer the arc to the arc chutes.
The current-carrying components are assembled on the
back frame, which provides the required mechanical sup-
port and insulating structure. The conductive compo-
nents are the studs for external connections, the movable
and stationary contact sets, and the pivots for the movable
contacts.
The interrupter components are the arcing contacts, the
arc runners mounted on the back base, and the removable
arc chute assemblies.
In addition to these basic components, a breaker may be
equipped with a combination of accessories and interlock-
ing devices.
2.2 Frame Sizes
The EntelliGuard breakers covered in this manual are
available in 800-ampere, 1600-ampere, and 2000-ampere
frame sizes. These values represent the maximum
continuous-current rating of each frame. In addition,
each breaker carries a specific rating that is determined by
the current sensor ampere rating or the maximum setting
of the EntelliGuard Messenger™ with which it is used.
2.3 Operation
EntelliGuard breakers are available with either manual or
electric operation. The mechanism closing springs of
manually operated breakers are charged by operating the
charging handle on the front of the breaker.
Electrically operated breakers contain an electric
Charging Motor that charges the closing springs, a
Remote Close accessory with antipump to close the
breaker, and a Shunt Trip to open the breaker. External
control power is required to energize the motor and its
control circuit. All breakers are equipped with a manual
charging handle so that the closing springs can be
charged without motor control power.
2.4 Fused Models
Internally fused breakers are available in 800- and 1600-
ampere frame sizes. They are not interchangeable with
unfused breakers, since fused breakers require deeper
compartments to accommodate the fuses.
2.5 Mounting
EntelliGuard breakers are designed for draw-out
mounting. Draw-out breakers are easily installed into or
removed from their switchgear cubicle. They are
equipped with a racking mechanism, which is used to
insert or withdraw the breaker, and primary and
secondary disconnects, which connect and disconnect
automatically.
2.6 EntelliGuard Messenger™
EntelliGuard low-voltage power circuit breakers are
intended for use in Entellisys™ Low-Voltage Switchgear
only. The breaker frames do not contain trip units or
current transformers. Thus, the EntelliGuard circuit
breaker must be used in concert with the EntelliGuard
Messenger and the current transformers mounted within
the switchgear cubicle. For installation and operation of
the EntelliGuard Messenger, see DEH231 and DEH234.
2.7 Interruption Ratings
Table 2 lists the short-circuit current that each breaker
type is rated to interrupt for each maximum rated voltage.