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MAINTENANCE
ELECTRICAL SERVICE LIFE
The electrical service life of the vacuum
interrupter is defined by the electrode wear and
the
number
of
(mechanical life).
Contact with energized
DANGER
components can cause
severe injury, death and
property damage. Turn off
and lock out primary and
auxiliary circuit power
before performing these
checks. Control voltage
must be present to perform
these checks. Use extreme
caution.
Checking moving interrupter
WARNING
or auxiliary contact can
pinch or damage fingers or
hands. Keep clear of
interrupters and auxiliary
parts when closing
contactor.
To determine electrode wear, measure the
distance between the lever and washer in the
closed (ON) state, as shown in. This dimension
is called the "wipe".
values. If the 0.5mm contact wear gauge
cannot be inserted, then the end of the service
life has been reached. The maximum number
of open/close operations is 500,000 regardless
of the magnitudes of the currents interrupted.
Contact Toshiba for information regarding
replacement of the vacuum interrupters.
Figure 14 – Interrupter Wipe Measurement
open/close
operations
See Table 3 for wipe
To determine the wear of the auxiliary contacts,
measure the auxiliary contact overtravel.
measure this distance, close the contactor,
depress the auxiliary contact operating lever to
the end of its travel.
contactor operating bracket and the operating
lever.. (Figure 14). See Table 3 for values.
Figure 15 – Aux. Overtravel Measurement
LUBRICATION
To maximize service life at each inspection
check the movable interrupter shafts (Figure 10
– Point A) and the nut and bearing surfaces
(Figure 10 – Point B) for lubrication. If they are
dry or the grease is old and stiff, clean surfaces
and apply a thin layer of Toshiba B7 grease.
Wipe
Figure 16 – Grease Application Locations
Measure between the
Overtravel
A
B
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