Siemens SIMOTICS M-1PH8 - Page 192

DC connection
The basic curve of the voltage when the excitation winding (coil) (1.2) is switched o󹪜 is as
follows.
W
W
0
8
;0
8%
89PD[
W
W

0
U
B
Operating voltage (coil voltage)
U Transient voltage
Figure5-8 Basic curve of the voltage when turning o󹪜 the excitation winding
NOTICE
Overvoltages when switching o󹪜
The voltage peak U
Vmax
when switching o󹪜 can reach several 1000 V in the millisecond range
without a protective circuit.
The excitation winding (coil) (1.2), switching contacts and electronic components can be
destroyed.
Sparks form at the switch on switch-o󹪜.
• When it is switched o󹪜, the current must therefore be reduced via a snubber circuit. This also
limits the voltages. The maximum permissible overvoltage when switching o󹪜 must not
exceed 1500V.
If Kendrion Binder recti󹪝ers are used, the protective circuit for the internal electronic
components and for the excitation winding (coil) (1.2) is integrated. This does not apply
Motor components and options
5.2Options
1PH8 SIMOTICS M main motors
190 Con󹪝guration Manual, 12/2022, A5E51895839A