Harris Platinum Z2 CD, Руководство пользователя

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WARNING: Disconnect primary power prior to servicing.
Overall System Theory
4.5 Detailed Power Supply Descriptions
4.5.1 3-Phase PA Power Supply
Refer to the Overall System Block Diagram in the schematic package for the
following discussion. The transmitter 3 phase AC inputs connect directly to K1, the
AC mains contactor. The transformer side of the contactor is connected to A17TB1
on the front of the power supply tray. The output side of A17TB1 connects directly
to power transformer T1 primary. T1 primary will be tapped for DELTA (3 wire) or
WYE (4 wire) depending on the site AC voltage input and must be tapped for the
proper AC input voltage. The tapping chart can be found on the Overall System
Block Diagram.
The transformer has 2 WYE configuration secondaries with the center connection
being the rectified DC output of 52Vdc. The two secondary outputs are combined
via L1 and L2. C1 and C2, 120,000uF filter caps, provide the final filtering.
Each of the transformer secondary taps is connected to a Rectifier Board. The
secondaries of T1 use the unique tap switching design to give a small window of
coarse regulation (approximately 2Vdc change per tap or 6 volt total) to compensate
for 3 phase AC line variations.
4.5.1.1 Rectifier Board
The Rectifier Board contains the SCRs which are used for the tap switching as well
as rectification of the 3 phase AC. Each secondary winding has four taps, see Figure
4-13. Each of these taps have one SCR to ground. The Power Supply Controller can
turn on any one of the four SCRs at a given time. If the voltage is not high enough at
the DC output, the PS Controller can change the transformer turns ratio by turning
on a different SCR and therefore utilizing a different secondary tap. The taps closest
to the center will provide the least amount of secondary turns in circuit and will
therefore give the lowest DC output voltage. This means that the taps which are
furthest from the center will give the highest DC output voltage due to more active
turns in the secondary.
There are two rectifier boards mounted on the top of each power transformer. The
two boards were originally made as one board which is broken apart for assembly.
Therefore, there is an “A” side and a “B” side, both of which are shown on the same
schematic. The left side of the schematic is the “B” side and the right side is the “A”
side (except on sheet 3 which is “B” side only). There is also only one part number
for both boards. The “A” Rectifier Board is for the transformer secondary “A” with
the “B” Rectifier Board used with transformer secondary “B”. The Rectifier Boards
are operated in parallel and are tied together by a ribbon cable, J3, which is shown
in the middle of the schematic connecting the “A” and “B” sides.