Switching inductive loads – Fluid Components International FS10A User Manual

Page 11

FS10 Series

Fluid Components International LLC

(OEM)

Switching Inductive Loads

If the FS10A relay contacts are to be used to energize or de-energize an external relay, diode suppression must be used across the external relay coil.

Use the guidelines in the following example to select the proper diode.
A Tyco Electronics relay K10P-11D15-24 is used as a slave relay. The DC coil voltage is specified at 24 Vdc and the specification indicates a coil

resistance of 650

Ω. The DC coil current is calculated by dividing the Rated coil power by the Rated Voltage Vdc or dividing the Rated Voltage Vdc by

the Coil resistance. In this case the current through the coil will be around 37mA (24/650). Refer to the K10P-11D15-24 data sheet.
It is recommended the Diode Reverse Voltage (Vr) rating be twice or greater the voltage across the relay and the diode forward current (IF) rating be

greater than the relay current. Diodes 1N914 or 1N4148 meet these limits for this case.