Fastener Check; Manual Spring Charging And Contact Erosion Checks; Figure 16 Contact Erosion Check Mark - Siemens 3AH Series Instructions Manual

Maintenance

Fastener Check

Inspect all fasteners for tightness. Both lock-n uts a n d retain­
ing rings are used. Replace a ny fasteners that a ppear to have
been frequently removed and replaced.

Manual Spring Charging and Contact Erosion Checks

Perform the M a nu a l Spring Charging Check conta ined in the
section describing the Installation Check and I n itia l Function­
al Tests. The key steps of th is procedure are repeated here:
1. I nsert the hand charg i n g crank into the m a n u a l charge
socket at the front of the operator control panel. Turn
the cra n k clockwise (about 45 revolutions) to charge the
closing spri n g . Conti nue cra n king until the Charged flag
a ppears 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 fau lt cu rrents are interrupted or when the
vacu u m interrupter is nearing the limit of its contact life.
Determination of acceptable contact cond ition is checked
by the visibility of the white contact erosion m ark shown
in Fig ure 1 6. The white contact erosion mark is located
on the movable stem of the vacuum interru pter, near the
plastic guide bushing.
The contact erosion check procedure is:
a . Be sure the circuit breaker pri mary contacts are Closed.
b. Observe the wh ite contact erosion mark ( Figure 1 6) of
each pole. When a ny part of the white contact ero­
sion mark is visible, contact wear is within acceptable
limits.
A
High Speed Moving Parts. Can cause
+
serious injury.
Opening spring is charged. If trip latch is
moved, the stored energy springs will dis­
charge rapidly.
Avoid physical contact with circuit breaker
parts su bjected to sudden, high speed move­
ment.
4. Press the red Open pushbutton after completing the con­
tact erosion check. Visually verify the Discharge condition
of the closing spring and that the circuit breaker contacts
are Open.
5. Press the black Close push button. Nothing should happen.
The manual spring check should d emonstrate smooth
operation of the operating mechanism.
WARNING
+
Figure 1 6. Contact Erosion Check Mark
Varnum
I nterrupter
White Contact
Erosion Mark
22