Eaton 36W-VAC25, Instructions For Installation, Operation And Maintenance

Page: 35 / 48

I.B. 3A74499B
Page 29
Effective 11/97
Figure 6-2 Vacuum interrupter showing contact erosion
indicator with breaker open (shown here for clarity pur-
poses only).
Figure 6-3 Vacuum interrupter showing contact erosion
indicator with breaker closed (indicators are checked
only when breaker is closed).
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
In W-VAC breakers, 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 of dry paper towel. In case there is
any tightly adhering dirt that will not come off by wiping,
it can be removed with a mild solvent or distilled water.
Be sure that the surfaces are dry before placing the
breaker in service. If a solvent is required to cut dirt,
use Stoddard’s Solvent Cutler-Hammer 55812CA or
commercial equivalent. Secondary control wiring
requires inspection for tightness of all connections and
damage to insulation.
6-7 INSULATION INTEGRITY CHECK
Primary Circuit:
The integrity of primary insulation may be checked by
the AC high potential test. The test voltage depends
upon the maximum rated voltage of the breaker. For
the breakers rated 12 kV and 15 kV the test voltages
are 21 kV and 27 kV rms respectively.
Conduct the test as follows:
Close the breaker. Connect the high potential lead of
the test machine to one of the poles of the breaker.
Connect the remaining poles and breaker frame to
ground. Start the machine with output potential at zero
and increase to the test voltage. Maintain the test volt-
age for one minute. Repeat for the remaining poles.
Successful withstand indicates satisfactory insulation
strength of the primary circuit.
If a DC high potential machine is used, make certain
that the peak voltage does not exceed the peak of the
corresponding AC RMS test voltage.
Secondary Circuit:
Isolate the motor by pulling apart the two insulated quick
disconnecting terminals in the two motor leads provided
for this purpose. Connect all points of the secondary
!
WARNING