FB120A Beacon Failure Alarm Relay

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SKU: SSA-FB120A Category:


FB120A Beacon Failure Alarm Relay


The FB120A and FB230A are used to monitor the operation of one two-lamp incandescent beacon and one beacon flasher (or auxiliary module). The flasher and lamps are monitored by sensing the flow of current in the circuit. If the lamp(s) or the flasher fail to operate properly, a solid-state output and an isolated SPDT relay energize. When connected to a site monitoring system, this unit provides the remote beacon monitoring protection required by the FAA/FCC. On a multiple beacon structure, one unit is required for each two-lamp incandescent beacon (one unit per beacon for LED beacons).


If one lamp in an incandescent beacon fails, the relay and solidstate lamp failure outputs energize after 10s. If the flasher fails in the ON or OFF condition, the relay and the solid-state flasher failure output energizes after 6s. If both failures occur, all three outputs energize after their trip delays.
Note: If both incandescent lamps fail, all three outputs will energize. The relay and solid-state flasher failure output energizes after 6s, and the solid-state lamp failure output energizes after 10s.



  • Toroidal current sensing
  • Failsafe beacon monitoring
  • One isolated, 5A, SPDT alarm output plus two, 1A, solid-state line voltage alarm outputs
  • Fixed trip delays for flasher (6s) and lamp (10s) failures



Input Voltage
FB120A 120VAC ±15%
FB230A 230VAC ±15%
AC Line Frequency 50/60Hz
Lamp Socket Voltage ±10%; 50/60Hz
Alarm Outputs
Type 3 total - 1 relay, 2 solid state;
One isolated SPDT relay rated 5A resistive
Two solid-state line voltage outputs rated
0.5A steady, 5A inrush
Lamp Failure Detection
FB120A For two 620W or 700W lamps
FB230A For two 500W or 700W lamps
Trip Delays
Flasher Failure Fixed at 6s; -0/+40%
Lamp Failure Fixed at 10s; -0/+40%
Lamp Failure (Red) Glows when one or both lamps fail
Flasher Failure (Red) Glows when the flasher fails
Circuitry Encapsulated
Mounting Surface mount with two #6 (M3.5 x 0.6) screws
Dimensions H 88.9 mm (3.5”); W 63.5 mm (2.5”);
D 44.5 mm (1.75”)
Termination 7 position barrier block for 20 AWG (0.5 mm2)
to 14 AWG (2.5 mm2) wire
Temperature -55° to 60°C / -55° to 85°C
Weight ≅ 7 oz (198 g