888-2406-002
4-17
WARNING: Disconnect primary power prior to servicing.
Overall System Theory
4.4.1.2.1 Soft Start
During transmitter turn on, a fifth set of SCRs is activated, See Figure 4-9. These
are connected to the lowest voltage output tap (the one with the fewest secondary
turns) of transformer secondary “B”. However, the Soft Start SCRs are connected
through a common surge limiting resistor to ground, instead of the direct ground
connection provided with the rest of the SCRs. This allows the “Soft Start” by
limiting the maximum surge current while charging the power supplies. The soft
start lasts for about two seconds during turn on. After the two second soft start the
resistor is bypassed by activating the normal run-mode SCRs which are also
attached to the lowest voltage output tap but connect directly to ground. This allows
the supplies to come up to full charge. If the voltage is not high enough, the Power
Supply Controller will activate the next highest tap to increase the voltage. It will
continue this process until the DC output voltage is approximately 52Vdc or it
reaches the highest tap.
4.4.1.2.2 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.
Figure 4-9
Simplified 3-Phase PA Power Supply Soft-Start and Discharge
Summary of Contents for Platinum Z2 CD
Page 4: ...888 2406 002 WARNING Disconnect primary power prior to servicing ...
Page 6: ...888 2406 002 WARNING Disconnect primary power prior to servicing ...
Page 8: ...888 2406 002 WARNING Disconnect primary power prior to servicing ...
Page 10: ...888 2406 002 WARNING Disconnect primary power prior to servicing ...
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 ...