Checking Contact Erosion - Siemens UL 489 Operating Instructions Manual

24.5

Checking contact erosion

It is strongly recommended that the breaker's internal contacts be inspected on a regular basis. Load breaking and short-circuit trips cause
contact erosion. The WL circuit breaker is equipped with a contact erosion indicator for monitoring wear of the circuit breaker's internal
contacts.
Hazardous voltage.
Will cause death, serious personal injury, or equipment damage.
Turn off and lock out all power supplying this equipment before working on this device.
High speed moving parts.
Will cause serious personal injury.
Do not place hands or objects within the arc chamber.
- OPEN circuit breaker the circuit breaker and discharge the closing spring
- Move the circuit breaker into the withdrawn position in the cradle
- Manually charge the closing spring
- Close the circuit breaker
- Remove the arc chutes
View with the circuit breaker closed
(1) Indicator pin
(2) Indicator pin is visible in the big recess
(3) Indicator pin is no longer visible
(4) Arcing tip
(5) Arc Chamber
If the indicator pin is no longer visible, the circuit breaker must be replaced.
For the visual inspection of fixed-mounted circuit breakers, use a mirror if required.
-
24 – 9
DANGER
WARNING
 (page 6-4)
 (page 6-7)
 (page
24-6).
(5)
 (page 24-2)
 (page 24-3)
(1)
0071-1
(4)
(2)
(3)