Contact Erosion And Wipe; Insulation - Eaton VCP-W Instructions For Installation, Operation And Maintenance

IB131006EN
Figure 6-2 Vacuum Interrupter Showing Contact Erosion
Indicator with Breaker Open (Shown Here for Clarity
Purposes Only)
SOME DC HIGH POTENTIAL UNITS, OPERATING AS
UNFILTERED HALF-WAVE RECTIFIERS, ARE NOT
SUITABLE FOR USE TO TEST VACUUM
INTERRUPTERS BECAUSE THE PEAK VOLTAGE
APPEARING ACROSS THE INTERRUPTERS CAN BE
SUBSTANTIALLY GREATER THAN THE VALUE
READ ON THE METER.

6-5 CONTACT EROSION AND WIPE

Since the contacts are contained inside the interrupter,
they remain clean and require no maintenance. However,
during high current interruptions there may be a minimum
amount of erosion from the contact surfaces. Maximum
permitted erosion is about 1/8 inch. To determine
contact erosion, close the breaker and observe the
vacuum interrupter moving stem from the rear of the
breaker. If the mark on each stem is visible, erosion has
not reached maximum value thus indicating satisfactory
contact surface of the interrupter. If the mark is not
Visible, the pole unit assembly must be replaced (Figures
6-2 and 6-3).
The adequacy of contact wipe can be determined by
E f f ec t iv e 0 7/ 2 0 1 7
Courtesy of NationalSwitchgear.com
CAUTION
Figure 6-3 Vacuum Interrupter Showing Contact
Erosion Indicator with Breaker Closed (Indicators
are Checked Only When Breaker is Closed)
Observing the vacuum interrupter side of the operating
rod assembly on a closed circuit breaker. Figure 6-4
shows the procedure for determining the contact wipe. If
the wipe is not adequate, the vacuum interrupter
assembly (pole unit) must be replaced. A field
adjustment is not possible. Refer to paragraph 7-3.2 for
a replacement procedure.
FAILURE TO REPLACE A POLE UNIT ASSEMBLY
WHEN CONTACT EROSION MARK IS NOT VISIBLE
OR WIPE IS UNSATISFACTORY, WILL CAUSE THE
BREAKER TO FAIL TO INTERRUPT AND THEREBY
CAUSE PROPERTY DAMAGE OR PERSONAL
INJURY.

6-6 INSULATION

Type VCP-W Circuit Breaker insulation maintenance
primarily consists of keeping all insulating surfaces
clean. This can be done by wiping off all insulating
surfaces with a dry lint free cloth or dry paper towel. In
case there is any tightly adhering dirt that will not come
off by wiping, it can be removed with mild solvent or
distilled water. Be sure that the surfaces are dry before
placing the circuit breaker
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