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Types SDV-R and SDV-R-AR distribution circuit breakers |
Instruction manual
Manual spring-charging and
contact-erosion checks
Perform the manual spring-charging check
contained in the section describing the
installation check and initial functional
tests. The key steps of this procedure are
repeated here:
1. Insert the hand-charging crank into the
manual-charge socket at the front of
the operator control panel. Turn the
crank clockwise to charge the closing
spring. Continue cranking until the
CHARGED flag appears in the window of
the spring indicator.
2. Press the Close (black) pushbutton. The
contact-position indicator on the
operator control-panel should indicate
that the circuit breaker contacts are
closed.
3. Perform the contact-erosion check.
Contact erosion occurs when high fault-
currents are interrupted. Determination
of acceptable contact condition is
checked by the visibility of the white
contact-erosion mark shown in Figure
25: Contact-erosion mark dot (shown
with circuit breaker OPEN). The white
contact-erosion mark is located on the
movable stem of the vacuum
interrupters, near the plastic guide-
bushing.
The contact-erosion check procedure is:
• Be sure the circuit breaker primary
contacts are closed.
• Observe the white contact-erosion mark
(refer to Figure 17) on each pole. When
any part of the white contact-erosion
mark is visible, contact wear is within
acceptable limits. A mechanic’s mirror is
a convenient means for viewing the
contact-erosion mark on each vacuum
interrupter.
4. Press the Open (red) pushbutton after
completing the contact-erosion check.
Visually verify the discharged condition
of the closing spring and that the circuit
breaker contacts are open.
5. Press the Close (black) pushbutton.
Nothing should happen. The manual-
spring check should demonstrate
smooth operation of the operating
mechanism.
Electrical control checks
The electrical controls of the circuit breaker
should be checked during inspections to
verify absence of any mechanical damage,
and proper operation of the automatic
spring-charging and close and trip circuits.
Unless otherwise noted, all of these tests
are performed without any control power
applied to the circuit breaker.
High-speed moving parts.
Can result in serious injury.
Tripping spring is charged. If trip latch is moved, the stored-energy
springs will discharge rapidly.
Stay clear of circuit breaker components that are subject to sudden,
high-speed movement.
Figure 25: Contact-erosion mark
