Siemens 3RK1308‑0 00‑0CP0 Series Equipment Manual page 85

Switching cycle parameters
The following table shows all the parameters that you have to consider for calculation of the
permissible switching cycle:
Parameters
Starting time t
Startup
Starting current I
Startup
Motor operation time t
Motor
Rated operational I
e
current
Motor OFF time: t
Off
Switching cycle T [s]
interval
You use the switching cycle interval time to determine the permissible starting frequency per
hour as follows:
Motor starter (3RK1308‑0**00‑0CP0)
Equipment Manual, 11/2019, A5E34821005002A/RS-AC/003
Description
[s] Time during which the motor
accelerates up to its operating
speed from standstill
[A] Root-mean-square of the motor
current that flows during the
starting time. It is considered as a
multiple x of the rated value of the
motor I
rated_motor
parameterized rated operational
current I .
e
I [A] = x * I
Startup
[s] Time in which the motor is in
operation after startup.
[A] Root-mean-square of the motor
current in the operating phase after
the starting time or the
parameterized value I
motor starter
[s] Idle time of the motor within the
switching cycle
Total of t t
Off, Motor
Conditions
The maximum is determined by the
parameterized tripping class and the intrinsic
device protection (see also Overload protection
(Page 76)).
The maximum is the permissible current of the
relevant device class. Consider additional idle
times in the case of starting currents in excess
of 65 A (see example graphics).
or of the
(Also see: Overload protection (Page 76) and
the example graphics)
[A]
e
-
The permissible I
adjustment range of the motor starter used and
its ambient temperature (see also:
of the Overload protection (Page 76)).
e
Consider additional idle times in the case of
starting currents in excess of 65 A
(see example graphics).
and t The maximum time is 300 s.
Startup
Functions
6.6 Calculating switching cycles
is determined by the
e
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