5. Commissioning, operation
5.2.7 Contact protection measures
Mechanical contacts must not exceed the specified electrical values for switching
current, switching voltage and switching power independent of each other, not even for
a short time only.
EN
For capacitive or inductive loads one of the following protective circuits is
recommended:
Inductive load with DC voltage
With DC voltage the contact protection can be achieved via a free-wheeling diode,
connected in parallel to the load. The polarity of the diode must be arranged so that it
closes when the operating voltage is on.
Example:
Contact protection
measure with free-
wheeling diode
Inductive load with AC voltage
With AC voltage two protection measures are possible:
Example:
Contact protection
measure with voltage-
dependent resistor VDR
Example:
Contact protection
measure with RC element
18
Contact
Diode
Load
WIKA operating instructions, model GDM-RC-100
Load
Load