Eaton 120VCP-W25, Инструкции по установке, эксплуатации и техническому обслуживанию

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IB131006EN
Page 41
Effective 07/2017
5-5 INTERLOCKS AND INTERFACING
Refer to Paragraph 4-9 of this manual for detailed
information concerning circuit breaker interlocks and
their interfacing with a switchgear structure
compartment. In addition, refer to the instruction
manual supplied with the switchgear assembly.
5-6 LEVERING MECHANISM
The purpose of the levering device is to move the circuit
breaker between the TEST and CONNECTED
positions. For Type VCP-W circuit breakers, the device
is a drive screw and drive nut. Although the device is
mounted in the switchgear compartment, a brief
description here will help understand the operation
(Figures
4-2 and 4-4 ) . For additional information on the
insertion and removal of a circuit breaker from its
compartment refer to paragraph 4-8.1 in this manual.
The levering device consists of a drive screw, a drive
nut, two side rails and a sliding cage. In the TEST
position, the nut is all the way to the front. As the circuit
breaker is pushed in, the levering latch snaps on the
nut. Turning the crank clockwise while pushing forward
advances the circuit breaker toward the CONNECTED
position. During this travel, the floor tripper TRIP roller
is lifted up holding the circuit breaker trip free. When the
circuit breaker reaches the CONNECTED position, the
crank cannot be turned any further. A red flag indicates
that the circuit breaker is fully engaged.
If the circuit breaker is closed in the CONNECTED
position, the slider cannot be pushed forward to permit
engagement of the levering crank. After tripping the
circuit breaker, the levering crank can be engaged and
the circuit breaker withdrawn to the TEST position by
turning the levering crank counterclockwise. This
position is indicated by no further motion of the crank.
The circuit breaker levering latch can be disengaged
only when the circuit breaker is in the TEST position by
lifting the latch release. As the circuit breaker is
withdrawn, it comes out with the contacts open and the
springs discharged because of the floor tripping and
spring release interlocks.
5-7 OPERATIONS COUNTER
All circuit breakers are equipped with a mechanical
operations counter. As the circuit breaker opens, the
linkage connected to the pole shaft lever advances the
counter reading by one (Figure
3-3 ) .
5-8 GROUND
CONTACT
The ground contact is an assembly of spring loaded
fingers providing a disconnectable means for grounding
the circuit breaker chassis, after it has been inserted
into a switchgear structure. The ground contact is located
on the left side of the circuit breaker under the
mechanism bottom pan. An extension of the switchgear
ground bus is secured to the cell floor in such a position
to engage the ground contact automatically, when the
circuit breaker is moved into the TEST position. It
remains engaged in all other circuit breaker positions
within the cell (Figures
4-2 and 4-4 ) .
5-9
MOC AND TOC SWITCH OPERATIONS
The MOC (mechanism operated control) switch
operator is coupled to the pole shaft (Figure
4-4 ) . In the
TEST and CONNECTED positions of the circuit
breaker, the operator aligns directly above the MOC
switch bell crank levers in the compartment. As the
circuit breaker closes, the operator moves down and
pushes the bell crank lever to change the MOC switch
contact position. Thus, the MOC switch contacts operate
in the same manner as the auxiliary switch contacts in
the circuit breaker. Although the MOC switch operator is
provided on all circuit breakers, the compartment
mounted MOC switches are only provided when
specified with the switchgear order.
The TOC (truck operated control) switch operator is
mounted inside the right foot of the circuit breaker
(Figure
4-4 ) . It operates the TOC switch as the circuit
breaker moves to the CONNECTED position in the
switchgear compartment.
Courtesy of NationalSwitchgear.com