Maintaining The Main Contact System - Siemens SINOVA Manual

Arc chute article numbers
Size 1
Breaking capacity S, 1 pc.
Size 2
Breaking capacity S, 1 pc.
4.7

Maintaining the main contact system

The main contacts can be replaced as often as required until the circuit breaker has reached
its maximum mechanical service life including maintenance. As soon as the circuit breaker
has reached its maximum mechanical service life with maintenance, it must be replaced.
The maximum mechanical service life of the circuit breaker depends on the total number of
operating cycles achieved. A distinction is made between electrical and mechanical operating
cycles.
• Electrical operating cycles:
Every switching operation (ON or OFF) of an air circuit breaker with current flow via the
main contacts up to the maximum rated current is considered an electrical operating
cycle. Due to the current flow, wear of the contacts is higher here than in case of a purely
mechanical operating cycle.
• Mechanical operating cycles:
Every switching operation (ON, OFF) of an air circuit breaker, with or without current
flow, is considered a mechanical operating cycle.
The electrical operating cycles are thus a subset of the mechanical operating cycles. The
number of mechanical operating cycles is usually greater than the number of purely
electrical operating cycles; they can be equal at most.
3WJ mechanical service life
Endurance (operating cycles)
3WJ1108, 3WJ1110, 3WJ1112, 3WJ1116
With maintenance
(one time)
3WJ1220, 3WJ1225
With maintenance
(one time)
3WJ1232, 3WJ1240
With maintenance
(one time)
6)
3WJ Air Circuit breakers
Operating Instructions, 12/2022, L1V30828903001-01
Mechanical
6)
Electrical (up to
440 V AC)
Mechanical
6)
Electrical (up to
440 V AC)
Mechanical
6)
Electrical (up to
440 V AC)
Maintenance means: Replace main contacts and arc chutes.
Inspection & Maintenance
4.7 Maintaining the main contact system
Article number
3WJ9111-0AP31
3WJ9111-0AP32
12000
8000
10000
4000
10000
4000
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