14
WIKA operating instructions gas density monitor model GDM-63
EN
14502554.01 07/2021 EN/DE
Overcurrent protectors
The instruments do not provide for incorporated overcurrent protectors. Should protec-
tors be required, the following values in accordance with EN 60947-5-1 are to be
recommended.
■
Voltage 24 V: 2 A
■
Voltage 250 V: 1 A
5.2.2 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.
For capacitive or inductive loads we recommend one of the following protective circuits:
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.
Inductive load with AC voltage
With AC voltage two protective measures are possible:
Example:
Contact protection
measure with free-
wheeling diode
Contact
Diode
Load
Example:
Contact protection measure
with voltage-dependent
VDR resistor
Example:
Contact protection
measure with RC element
Load
Load
5. Commissioning, operation
