Switching Frequency - Siemens SIRIUS M200D Manual

Technical data

8.7 Switching frequency

8.7 Switching frequency
The switching frequency specifies how many switching cycles can be performed in one time
unit (e.g. in 1 hour) with the switching device under normal operating conditions.
If motors are switched too often, this causes the thermal motor model to respond.
The maximum permissible switching frequency depends on the following operating data:
● Rated current I
● On time motor
● Degree and type of protection
● Ambient conditions such as
– Temperature
– Mounting position
On time motor
The relative on time in % is the ratio between the load duration and the cycle duration on
loads that are switched on and off frequently.
The on time can be calculated using the following formula:
ED
t
s
t
b
t
p
Graphics-based representation:
Figure 8-1
148
of the motor
e
ON duration [%]
Starting time [s]
Operating time [s]
Idle time [s]
On time motor
M200D AS-Interface Standard
Manual, 08/2014, A5E02548958A/RS-AA/004