21
Instruction Book
IB182017EN February 2017 www.eaton.com
5kV, 7.5kV, & 15kV DHP-VR
Replacement Circuit Breaker
The erosion indicator is easily viewed from the rear on the 7.5 or
15kV designs. Because of the nature of the 5kV 20WR element
inverted design, the erosion indicator is not easily viewed, although
it is possible with the use of a light and an inspection type mirror.
WARNING
FAILURE TO REPLACE THE INTERRUPTER ASSEMBLY WHEN INDICATED BY
THE CONTACT EROSION INDICATOR COULD CAUSE THE BREAKER TO FAIL,
LEADING TO DEATH, PERSONAL INJURY OR PROPERTY DAMAGE.
4.1.3 CONTACT WIPE AND STROKE
Contact wipe is the indication of the force holding the vacuum
interrupter contacts closed and the energy available to hammer the
contacts open with sufficient speed for interruption.
Stroke is the gap between fixed and moving contacts of a vacuum
interrupter with the breaker open.
The circuit breaker mechanism provides a fixed amount of motion
to the operating rods. The first portion of the motion is used to
close the contacts (i.e. stroke) and the remainder is used to further
compress the preloaded wipe spring. This additional compression
is called wipe. Wipe and stroke are thus related to each other.
As the stroke increases due to the erosion of contacts, the wipe
decreases. A great deal of effort and ingenuity has been spent in the
design of VR-Series breakers, in order to eliminate any need for field
adjustment of wipe or stroke.
WARNING
THERE IS NO PROVISION FOR IN-SERVICE ADJUSTMENTS OF CONTACT
WIPE AND STROKE. ALL SUCH ADJUSTMENTS ARE FACTORY SET AND
SHOULD NOT BE ATTEMPTED IN THE FIELD.
4.2 PHASE BARRIERS
Phase barriers are sheets of insulation located between the
interrupter pole assemblies and on the sides of the breaker frame.
The phase barriers are designed to isolate energized conductor
components in each phase from the adjacent phase and ground.
WARNING
ALL PHASE BARRIERS MUST BE IN PLACE BEFORE PLACING THE
CIRCUIT BREAKER INTO SERVICE. FAILURE TO HAVE THEM IN POSITION
CAN CAUSE DEATH, SERIOUS PERSONNEL INJURY AND/OR PROPERTY
DAMAGE.
4.3 BUSHINGS AND DISCONNECTING CONTACT
ASSEMBLIES
The line and load bushing assemblies, which are the primary
circuit terminals of the circuit breaker, consist of six silver plated
conductors. Multiple finger type primary disconnecting contacts
at the ends of the conductors provide means for connecting and
disconnecting the breaker to the bus terminals in the switchgear
compartment.
4.4 STORED ENERGY MECHANISM
The spring-type stored energy operating mechanism is mounted on
the breaker frame and in the front of the breaker. Manual closing
and opening controls are at the front panel (Figure Set 3.3). They
are accessible while the breaker is in any of its basic installation
positions. (See Section 5 in this manual)
The mechanism stores the closing energy by charging the closing
springs. When released, the stored energy closes the breaker,
charges the wipe and resets the opening springs. The mechanism
may rest in any one of the four positions shown in Figure 4.16 as
follows:
Figurt 4.3. DHP-VR Inttrrupttr Asstmbly
(29WR Shown)
Figurt 4.4. DHP-VR Inttrrupttr Asstmbly
(29WR Shown) (All Thrtt Polt Units)
