Precision Digital PD650 - Manual (Page 82)

Model PD650 Large Display Process Meter Instruction Manual
82
Switching Inductive Loads
The relay contacts on the Options Board are already protected with suppression
components (snubbers).
If additional suppression is required, this suppression can be obtained with RC
networks assembled by the user or purchased as a complete assembly. Refer to
the following circuits for RC network assembly and installation:
AC and DC Loads
Figure 26. AC and DC Loads Protection
Choose R and C as follows
R: 0.5 to 1
Ω for each volt across the contacts
C: 0.5 to 1 µF for each amp through closed contacts
Notes:
1. Use capacitors rated for 240 VAC.
2. Snubbers may affect load release time of solenoid loads, check to confirm
proper operation.
3. Install the RC network at the meter's relay screw terminals. An RC network
may also be installed across the load. Experiment for best results.
Low Voltage DC Loads
Figure 27. Low Voltage DC Loads Protection
Use a diode with a reverse breakdown voltage two to three times the circuit
voltage and forward current at least as large as the load current.