Checking Contact Erosion - Siemens UL 1066 Operating Instructions Manual

23.5

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 device 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- Move the circuit breaker into the withdrawn position in the cradle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 contact system must be replaced.
The contact system must also be replaced if:
- the end of the circuit breaker's mechanical service life according to its technical data has been reached (due to wear on the copper
braids).
- heavy wear of the arcing tip is visible
(triangular tips have lost approx. 5/16" of their original length)
23 – 10
DANGER
WARNING
 (page 6-4)
 (page 6-7)
 (page
23-6).
(5)
 (page 23-2)
 (page 23-3)
(1)
0071-1
(4)
(2)
(3)