Siemens 3VA1 100 A Manual page 128

Applications
3.2 Use of the 3VA1 breaker as a switch disconnector
Utilization categories for switch disconnectors
Utilization categories are differentiated according to the following criteria:
● The relationship between operational current and rated operational current
● The relationship between operational voltage and rated operational voltage
● Power factor (p.f.)
● Time constant
The utilization category is also identified by a letter:
A - for frequent operation
B - for infrequent operation, e.g. disconnectors which are used only to isolate parts of
electrical installations for maintenance purposes.
It is important to note, however, that the term "frequent operation" does not mean that the
switch disconnector may be used to start up, accelerate or shut down individual motors in
normal operation.
For example, a switch disconnector with a rated operational current I
operational voltage U
resistive and inductive loads including moderate overload only if it can conduct a making
current I of 480 A (3 x I
power factor of 0.65. This capability corresponds to utilization category AC-22A.
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of 400 V AC may be used for frequent switching of a mixture of
e
) and withstand a making voltage U of 420 V AC (1.05 x U
e
of 160 A and a rated
e
) with a
e
3VA molded case circuit breakers
Manual, 04/2015, A5E03603177010-02