Fig. 27: Pin assignment, plug socket,
change over contact (SG-30 with con-
nector in compliance with
EN175301-803)
5.9 Contact protection
measures
The Reed-switches used in the switch
contacts are designed to be very sen-
sitive to overload. To prevent destruc-
tion of the switch contact, the values
specified on the rating plate of the
switch contact must never be
exceeded (not even temporarily).
There is a risk of overload from:
n
inductive loads
n
capacitive loads
n
ohmic loads
Suitable measures must be taken to
protect against overload (see following
examples):
Inductive load
There is danger of voltage peaks from
inductive loads when switching off (up
to 10 times the rated voltage). Induc-
tive loads are caused by, e.g.:
n
Contactors, relays
n
Solenoid valves
n
Electric motors
Examples of protective measures:
Fig. 28: Example 1
Fig. 29: Example 2
Capacitive loads
There is a danger of high current
peaks from capacitive loads when
switching-on the switch contact
(exceeding rated current). Capacitive
loads are caused by, e.g.:
Installation und initial startup
Contact protection measures
03.09.2018
DWG Module BASICS Flow Monitor
45