Theory Of Operation; The Power Supply - TWR Lighting E-1DBSL Manual

DUAL MEDIUM INTENSITY LED/STROBE
3.0

THEORY OF OPERATION

3.1

THE POWER SUPPLY

The AC line is sent to transformers T1 through fuse F1, MOVMOD, and relay K1.
In order for K1 to energize and complete the circuit to T1, the safety interlock
switches (CSS & BSS) must be closed. The BSS (beacon safety switch) is located in
the base of the beacon. In order for the system to operate, the beacons and the power
supply must be closed and secured. The CSS (cabinet safety switch) is located in the
enclosure door of the control cabinet. This switch is a three (3) position switch that
can be pulled out or depressed by closing the door to complete the circuit.
Transformer T1 secondary outputs are around 1,100V AC. These outputs are sent to
the high voltage rectifier PCB (PCB #2) and converts the 1,100V AC to around
+550V DC and -550V DC in daymode operation. This high voltage is then used to
charge energy storage capacitor bank C103-C109. Resistor R31 is bypassed through
K5 during daymode operation.
When the light level drops below 3 foot candles, the photocell supplies 120V AC to
relay K3, and energizes it. The power is switched from the T1 to the red beacon
control circuit. That consists of a flasher (M1) and a timing module (M4), which will
flash the beacon, and a current sensing module (M2), which detects failures.
In the event of LED beacon failure or flasher failure, the K9 relay (failsafe relay) will
remove power from the K3 relay, de-energizing it. The power is then switched back
to the strobe control circuit (T1). The photocell continues to supply 120V AC to the
controller. This voltage is supplied to the K5 relay, which removes C103-C109 from
the discharge path leaving capacitor C102 in the circuit for failsafe mode operation.
Transformer T1 secondary outputs are converted from 1,100V AC at the PCB #2 to
around +700V DC and -550V DC for failsafe mode operation. This high voltage is
then used to charge the energy storage capacitor C102 through the current limiting
resistor R31, and the steering diode D5. The energy storage capacitor bank is
connected to the flashtube through the interconnecting tower wiring.
M.2006 MANUALS.E-1DBSL
REV. 08/10/04, 12/09/05, 2/08/06, 04/11/06 (load resistor)
REV. 06/21/06 (part numbers), 7/13/06 (Appendix & 6.0 Major Comp. List)
REV 10/20/06 (Appendix & parts lists)
REV. 04/10/07 (text)
MODEL E-1DBSL
10