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4.6 INTERLOCKS
m DANGER
INTERLOCKS ARE PROTECTIVE DEVICES FOR PERSONNEL AND
EQUIPMENT. DO NOT BYPASS, MODIFY, OR DISABLE ANY INTERLOCKS.
DOING SO COULD CAUSE DEATH, SEVERE PERSONAL INJURY, EQUIPMENT
DAMAGE AND/OR IMPROPER OPERATION.
There are several interlocks built into the VR-Series + vacuum
replacement circuit breakers. Each of these interlocks, though
different in form, duplicate or exceed the function of the original
circuit breaker's interlocks. These interlocks exist to safeguard
personnel and equipment. The basic premise behind the interlocking
arrangement on the vacuum replacement circuit breaker is that
the circuit breaker must not be inserted into or removed from a
live circuit while the main contacts are closed. Also considered in
the interlocking is that the circuit breaker should pose no greater
risk than necessary to the operator in or out of the circuit breaker
compartment.
4.6.1 RACKING-IN INTERLOCK
The racking-in interlock is designed to prevent moving the circuit
breaker into or out of the operating position, if the circuit breaker
contacts are closed. DHP-VR + interlocks are completely compatible
with the existing racking screw located in the existing DHP or DVP
assembly structure.
DHP-VR + circuit breakers utilize a racking-in interlock design that
is very similar to the design used on DHP circuit breakers. A key,
which is spring operated by the closing and opening action of the
circuit breaker, prevents racking of the circuit breaker, unless the
circuit breaker is open. Opening the circuit breaker removes the key
from the racking shaft key-way, and allows the circuit breaker to be
racked.
4.6.2 CIRCUIT BREAKER - CODE PLATE
This is a combination of a notched plate in the circuit breaker
compartment and interference bars on the circuit breaker, so that
only appropriately rated circuit breakers can be put into the circuit
breaker compartment of the metal-clad switchgear (Figure 4.5).
m WARNING
DO NOT REMOVE THE CODE PLATE FROM THE CIRCUIT BREAKER OR
CIRCUIT BREAKER COMPARTMENT UNLESS INSTRUCTED BY EATON'S
POWER BREAKER CENTER.
Figurt 4.5. Codt Platt
VR-Series
4.6.3 ANTI-CLOSE INTERLOCK
The anti-close interlock prevents discharging of the closing springs if
the circuit breaker is already closed (Figure 4.9, Item 11). When the
circuit breaker is closed, the interlock component moves away from
the spring release clapper so that it cannot lift the spring release
latch (9).
4.6.4 FLOOR TRIPPING AND CLOSING SPRING RELEASE
INTERLOCKS
The floor tripping and closing spring release interlocks operate to trip
the circuit breaker and discharge the closing spring when the circuit
breaker is inserted into the circuit breaker compartment to the 'Test'
position, or removed from the circuit breaker compartment. Cam
plates, on the circuit breaker compartment floor, lift trip levers on
the underside of the circuit breaker to trip the circuit breaker and/or
discharge the closing springs (Figures 4.6).
The floor tripping interlock also operates to hold the circuit breaker
trip-free while it is traveling between the 'Test' and 'Connect'
positions. This is to prevent accidental closing of the circuit breaker
in an intermediate position.
4.6.5 RAIL LATCH
Figurt 4.6. Floor Tripping Ltvtrs (Undtrntath Front Vitw)
The main function of the rail latch is to prevent damage to the
racking screw and nut. It also functions to latch the circuit breaker
in the 'Test' position, as described in the Inspection and Installation
section of this manual (Figure 4.7).
m DANGER
DO NOT FORCE THE CIRCUIT BREAKER INTO THE CIRCUIT BREAKER
COMPARTMENT. DOING SO MAY DAMAGE PARTS THEREBY RISKING
DEATH, SEVERE PERSONAL INJURY, EQUIPMENT DAMAGE AND/OR
IMPROPER OPERATION.
Figurt 4.7. Rail Latch
Instruction Book
IB182917EN September 2018 www.eaton.com
DHP-VR
+
Replacement Circuit Breaker
+
19
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