5-2.2 Contact Erosion Indicator; Type Vcp-Wr Series 20 Interrupter Assemblies; Type Vcp-Wr Series 18 Interrupter Assemblies; Type Vcp-Wr Series 29 Interrupter Assemblies - Eaton Cutler-Hammer VCP-WR 18 Series Instructions For The Use, Operation And Maintenance

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Figure 5-2 Type VCP-WR Series 20 Interrupter
Assemblies
Figure 5-3 Type VCP-WR Series 18 Interrupter
Assemblies

5-2.2 CONTACT EROSION INDICATOR

The purpose of the contact erosion indicator is to moni-
tor any erosion of the vacuum interrupter contacts.
Contact erosion is, however, very minimal over time with
Cutler-Hammer vacuum interrupters utilizing copper-
chrome contact material. If contact erosion reaches 1/8
inch, the interrupter must be replaced. A contact erosion
indicator mark is located on the moving stem of the
interrupter (Figures 7-2 and 7-3)
In order to determine if the contacts have eroded to the
extent that the interrupter must be replaced, observe the
erosion mark placed on each moving stem from the rear
of the breaker with the breaker closed. The interrupter is
satisfactory if the mark on the stem is visible with the
breaker closed. The entire interrupter assembly must be
replaced if the mark is no longer visible.
The erosion indicator is easily viewed from the rear of
the breaker on Series 18 and 29 VCP-WR breaker ele-
ments. Because the Series 20 VCP-WR breaker ele-
ment's interrupter assembly is inverted relative to Series
18 and 29 configurations, the erosion indicator is not
easily viewed. It is possible to observe the Series 20
indicator using a light and a dental type mirror.
Figure 5-4 Type VCP-WR Series 29 Interrupter
Assemblies
I.B. 8295A61H03
Effective 7/97