TWR Lighting E-2/3DB - 3 Theory of Operation; The Power Supply; The Flashtube

E-2/3DB CONTROLLER
E:\Documents and Settings\Administrator\Local Settings\Temporary Internet Files\OLK3\E2-3DB.doc
Rev. 01/13/00; Rev. 07/2000 o2L/H
Rev. 10/2000 (dwgs. 100239, 601, 601-01, 601-02, H02-258, 100031, 279L, 274S, 100089)
Rev. 06/21/00 (Reformatted Text; Revised Pg. 3 (2.4.1, 20 amp to 30 amp)
Pg. 12
3.0 THEORY OF OPERATION
3.1 THE POWER SUPPLY
The AC line is sent to transformers T2, and T2A through fuses F2, F3,
MOVMOD1, and relay K1. In order for K1 to energize and complete the
circuit to T2 and T2A, the safety interlock switch CSS, BSS, must be closed.
The BSS 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.
Transformers T2, and T2A secondary outputs are around 1,000V AC. These
outputs are sent to the high voltage rectifier PCB (PCB #2) and converts the
1,000V AC of each transformer to around +550V DC and -550V DC in
daymode and +700V DC and –550V DC in nightmode. This high voltage is
then used to charge the energy storage capacitors C102, C112, and C122
through current limiting resistors R31A, R31B, and R31C, and steering
diodes D5, D6, and D8, for nightmode operation. Resistors R31A, R31B,
and R31C are bypassed through K5A, K5, and K5C for daymode operation.
Energy storage capacitors bank C103-131 is used for the daymode
operation and are connected to the high voltage through the normally closed
contacts of relays K5A, K5B, and K5C. When the light level drops below 3
foot candles, the photocell supplies 120V AC to relays K5A, K5B, and K5C,
which removes C103-131 from the discharge path leaving capacitors C102,
C112, and C122 in the circuit for nightmode operation. The energy storage
capacitor banks are connected to the flashtube through the interconnecting
tower wiring.
3.2 THE FLASHTUBE
The flashtubes FTW1, FTW2, and FTW3 (daymode) and FTR1, FTR2, and
FTR3 (nightmode) are quartz tubes containing two (2) electrodes each. The
electrode at the positive (+) end is called the anode and is connected to the
positive side of the storage capacitors through inductors L1, L11, L2, L22,
L3, and L33. The electrode at the negative (-) end of the tube is called the
Cathode and is connected to the negative side of the energy storage
capacitors banks.