4-20
888-2406-002
WARNING: Disconnect primary power prior to servicing.
Overall System Theory
4.4.1.3.1 PA Power Supply Discharge
The PA Power Supply Discharge circuit also uses the Soft Start resistor to discharge
the 52Vdc PA supply. The discharge circuit is activated when the transmitter is
turned off. When the discharge circuit is active, it disables the SCRs to prevent the
supply from trying to turn on during a discharge cycle.
4.4.1.3.2 16VCT Secondary
There is a 16VCT secondary on each transformer whose output goes to the Rectifier
Board for that supply. It is rectified and used as the drive for the gates of the SCRs.
This is required due to the large gate drive current needed on the large single phase
SCRs. The rectified voltage from this secondary is called V+SCR on the Rectifier
Board. It is also fused on the Rectifier Board.
4.4.2
Low Voltage Power Supply
The Low Voltage Power Supply is a single PC board mounted in the rear of the
transmitter near the main contactor. It is designated A19 (assembly 19). The circuit
board is the same for the 3-Phase and single phase configurations, only the wiring to
and from the board is changed. It supplies DC voltages to all circuits in the
transmitter. These include:
•
+20VDC
•
-20VDC
•
+10VDC
These voltages are sent to the Rectifier boards and then on to the controller boards.
The board contains 3 relays, A19K1, A19K2 and A19K3. When the transmitter is
turned on, A19K1 activates the main contactor (simply called K1) which then
applies AC to the PA power Supplies, while A19K2 applies AC to the exciter(s).
A19K3 selects the low or high fan speed by actuating the fan speed select relay K2
which is mounted near the main AC contactor.
Summary of Contents for Platinum Z2 CD
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Page 70: ...3 14 888 2406 002 WARNING Disconnect primary power prior to servicing Operator Guide ...
Page 130: ...4 60 888 2406 002 WARNING Disconnect primary power prior to servicing Overall System Theory ...
Page 194: ...6 38 888 2406 002 WARNING Disconnect primary power prior to servicing Troubleshooting ...
Page 196: ...7 2 888 2406 002 WARNING Disconnect primary power prior to servicing Parts List ...