Specifications

The middle winding provides 12 Volts AC to the AC input of
bridge rectifier CR44. The negative output of CR44 is connected
to filter capacitor C11 and bleeder resistor R11. This supply is
further filtered by L3 and C14. Bleeder resistorR38 is connected
across C14. This forms the -12VDC or unregulated B- supply.
The positive output of CR44 is connected to filter capacitor C8
and bleeder resistor R8. This supply is the +12VDC or unregu-
lated B+ supply. Filter capacitor C210 and bleeder resistor R210
are installed to further filter the supply.
The lower winding provides 10 Volts AC to the AC input of
bridge rectifier CR45. The negative output of CR45 is connected
to filter capacitor C13 and bleeder resistor R13 and is the -8VDC
output. The positive output of CR45 is connected to filter
capacitor C12 and bleeder resistor R12 and is the +8VDC
output.
4.6.1.4 Power Distribution Boards
The Power Distribution Board distributes + and -8V, + and -12V
and + and -22V to other transmitter printed circuit boards. The
only components on the Power Distribution board are seven
connectors.
4.6.1.5 Servo Power Supply
The Servo Power Supply provides +24VDC, +20VDC, and
-20VDC. All Servos and switching relays are operated from this
supply.
Transformer T7 is a single phase transformer, with a tapped
primary winding for operation from different input voltages.
Circuit breaker CB6 protects the supply against overloads or
shorts on the supply output. T7 has a secondary winding with
taps to provide the different supply voltages.
The top winding provides AC to bridge rectifier CR49, which
forms the +24VDC supply. The output is connected to filter
capacitor C18 and bleeder resistor R39.
The middle winding provides AC to bridge rectifier CR48. The
negative output is connected to filter capacitor C19 and bleeder
resistor R41, and this forms the -20VDC supply.
The positive output is connected to filter capacitor C20 and
bleeder resistor R39, and this forms the +20VDC.
4.6.1.6 2L1 Motor Switch Supply
Two sets of wires are connected across the primary taps of T7,
that provide 110VAC for the 2L1 motors.
4.6.2
3 Phase AC Input
NOTE: 480V is used for simplicity, however the 3 Phase A\C
MAINS input can be from 365-505VAC.
3 Phase AC input conductors are directly wired to the top set of
contacts of K2 (SEE VIEW 5). RV1/RV2, RV3/RV4, and
RV5/RV6 protect the RF Amplifier Power Supplies from AC
transients. These MOV’s are connected to the 3 phase AC input
through F3, F4, and F5. Normally DS1, DS2, and DS3 on the
Power Supply Control Panel are illuminated GREEN when 480
VAC is present and the protection is active. If the MOV’s should
fail after they have provided protection from a transient, F3, F4,
and/or F5 will open and DS1, DS2, and/or DS3 will not be
illuminated GREEN. AC line monitor K10 is connected to the
3 Phase AC input and monitors the line for “phase imbalance”
and low line voltage. Should either of these conditions occur,
the monitor status line at terminal 7 will go low and turn OFF
the transmitter and display an RF AMP POWER SUPPLY A/C
MAINS FAULT.
4.6.2.1 Step Start Sequence
Refer to Figure 4-8, Simplified RF Amplifier Power Supply
Diagram and/or Schematic (843-5155-552), and VIEW 5 for
component location. When the RF Amplifier Power Supply is
first turned on, turn-on control logic on the Controller board
energizes solid state relay K3. K3 in turn energizes K1, the Step
Start relay, and 3 Phase ac power is supplied to transformers
A1T1A and A2T1A through three low-resistance high wattage
resistors R1, R2 and R3. The series resistance limits surge
current as power supply capacitors charge. When K1 energizes,
an auxiliary contact also closes and provides a +22 Volt “K1 has
closed” logic signal to turn-on control logic on the Controller
board.
After one second, the turn-on control logic energizes solid state
relay K4 which then energizes contactor K2. Heavy contacts on
K2 apply primary power directly to transformer A1T1A and
A2T1A. An auxiliary contact on K2 provides a +22 Volt “K2
has closed” logic signal to the turn-on control logic. About half
a second later, K3 opens and step-start contactor K1 is de-ener-
gized, completing the Step Start sequence.
4.6.2.2 RF Amp Power Supply
Refer to Figure 4-8, Simplified RF Amplifier Power Supply
Diagram and/or (843-5155-552). RF AMP Power supply A and
B are exactly the same except for component designators. For
discussion purposes supply A will be covered.
4.6.2.3 RF Amplifier Power Supplies
The voltagesgenerated by the RF Amplifier Power Supplies are:
a. +60VDC, for the Buffer Amplifier and the 1/8 and 1/16
step Binary amplifiers.
b. +115VDC, for the Predriver, RF Drivers D1-D14 and the
Driver Supply Regulator.
c. +230VDC, for the PAN RF Amplifiers, and the control
section of the Driver Supply Regulator.
Transformer T1A is a 3-phase, open frame power transformer.
The multiple windings in the primary allow an input voltage
rangefrom365 Vacto505 Vac.Threesets ofsecondarywindings
provide the ac power for the +230VDC and +115 VDC rectifier
assemblies.
The 12-phase, 230 Volt supply is derived from two of the
secondaries wired in an extended delta configuration and oper-
ating in parallel. The 230 volt, 6-phase rectified outputs from
CR1A through CR12A and CR1B through CR12B are com-
bined through Interphase transformer A1T2. Each pair of recti-
fiers are fused separately by fuses F1 through F12. Capacitors
C1 and C2 along with MOV’s RV9 and RV10 provide filtering
and protection for each rectifier assembly respectively.
The third secondary of T1A feeds the rectifier assembly of CR25
through CR30. The output from these rectifiers forms the +115
VDC. The rectifiers are fused by F13 through F15.
12/16/03 888-2339-002 4-13
WARNING: Disconnect primary power prior to servicing.