Siemens Sentron 3VA Manual page 484

Glossary
Rated short-time current
Permissible rms value of the AC component of the prospective short-circuit current which the
switching device is capable of conducting for a specific time period, e.g. from 0.05 s to 1 s
(thermal short-circuit strength).
Rated short-time withstand current
The rated short-time withstand current
current and characterizes the thermal strength of a circuit of a switchgear assembly under
brief load conditions. The rated short-time withstand current calculation normally refers to a
period of 1 s. The reference time must be specified if it deviates from the above. The rated
short-time withstand current is specified for the distribution and/or main busbars of a
switchgear assembly.
Rated ultimate short-circuit breaking capacity
The rated ultimate short-circuit breaking capacity
a molded case circuit breaker is capable of interrupting (test O - CO, formerly test sequence
P III). After the molded case circuit breaker has cleared the short circuit, it is capable of
tripping with increased tolerances under overload conditions.
Limit value of rated ultimate short-circuit breaking capacity
Rated uninterrupted current
The rated uninterrupted current
is a current that the device can conduct in uninterrupted operation (for weeks, months or
years). This current is specified by the manufacturer.
Rating
The rating is the power that a switching device is capable of switching at the associated
rated operational voltage in accordance with the utilization category, e.g. power contactor
utilization category AC-3:37 kW at 400 V.
Remote control
Or AUTO; method of remote operation of the motor operators via control cables, e.g. PLC.
Short circuit
Connection with a negligibly low impedance between two points of different potential in an
electric circuit. The short-circuit current is a multiple of the rated operating current. Short
circuits can cause thermal or mechanical damage to switching devices and other parts of an
electrical installation.
482
I
is specified as an rms value of the short-circuit
cw
I
is the maximum short-circuit current that
cu
I
of a switching device, e.g. a molded case circuit breaker,
U
3VA molded case circuit breakers with UL and IEC certification
I
.
cu
Manual, 01/2019, L1V30435333-01