© 2016 Littelfuse Protection Relays & Controls
Flashers and Tower Lighting Controls
Tower and Obstruction Lighting Controls
www.littelfuse.com/fb
Rev: 1-A-062316
Wiring Diagram
FB SERIES
Flasher & Incandescent Beacon Alarm Relay
Description
The FB Series is 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).
Operation
If one lamp in an incandescent beacon fails, the relay and solid-
state 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.
Features & Benefits
FEATURES BENEFITS
Toroidal current sensing
Reliable low cost monitoring of the flasher and
lamps through built-in CT and provides isolation
from the monitored circuit
Failsafe beacon
monitoring
Alarm monitors for failed incandescent lamps in
addition to flasher function
One isolated, 5A, SPDT
alarm output plus two,
1A, solid-state line
voltage alarm outputs
When connected to a site monitoring system, it
provides the remote beacon monitoring protection
required by the FAA / FCC.
Fixed trip delays for
flasher (6s) and lamp
(10s) failures
Prevents nuisance alarms
V = Voltage
B = Beacon
F = Flasher
T = Toroid
BRC = Flasher Bypass Relay Contacts
AR = FB Alarm Relay
BR = Bypass Relay Coil
FL = Flasher Failure LED
LL = Lamp Failure LED
AXL = Lamp Alarm Relay Coil
NOTE: Flasher module may be located on either the line or load side of the toroidal sensor.
Ordering Information
MODEL LINE VOTAGE LAMP TYPE
FB120A
120VAC
Incandescent Beacon
FB230A
230VAC
Incandescent Beacon
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