15
WIKA operating instructions gas density monitor model GDM-100
EN
14300397.03 07/2021 EN/DE/FR/ES
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:
Capacitive load
With capacitive loads elevated switch-on currents arise. These can be reduced by
series-connecting resistors in the supply line.
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
Examples: Contact protection measure with current-limiting resistor
Load
Load
U
B
R
1
U
B
R
1
5. Commissioning, operation
