TM 5-3895-374-24-1
GP470FA
APPENDIX B:
INTERMEDIATE RELAYS
When the damper actuator requires more than 3-1/2 Amps or 120 Vac, intermediate relays are required for controller
protection. The relays must be enclosed to protect personnel from electrical hazard. A NEMA 4 enclosure is required for
outdoor installations.
Provide a suitably sized fuse to protect the actuator. Wiring to the actuators and solid state relay terminals 1 and 2 should
be sized to accommodate the maximum expected current. #18 AWG wire is suitable for connections between the DPS
and solid state relay terminals 3 and 4.
Consult the manufacturer for the current required to drive the damper actuator. Solid state relays are available with 10
Amp, 25 Amp and 40 Amp ratings. Hauck recommends * Crydom relays which require a 6.8K Ohm 2W resistor between
terminals 3 and 4 as shown in the schematic diagram below.
Crydom Model
Rating
Voltage
A2410
10 Amps
48-280 Vac
A2425
25 Amps
48-280 Vac
A2440
40 Amps
48-280 Vac
*Manufactured by:
International Rectifier Inc.
1521 E. Grand Ave.
El Segunda, CA 90245
Phone: 213/322-4987
(page 3-48)
