Rockwell Automation SF3000 Parallel Gate Amplifier System - Manual (Page 20)

3-2 Parallel Gate Amplifier
3.2 PGA Power Supply Module Electrical Description
The PGA Power Supply module includes an internal +28 VDC regulated power supply
and a 28 volt to 5 volt DC-to-DC converter. The internal regulated supply requires a
115 VAC input. Its output provides the DC bus power for the six FET gate firing
circuits on each PGA module. The internal regulated supply also powers the
DC-to-DC converter, which in turn generates the +5 VDC output necessary for the six
biasing networks on each PGA module.
The Power Supply module also has provisions for interfacing with an optional,
externally-mounted regulated power supply if the application requires a DC bus
voltage greater than +28 VDC. The Power Supply module will work with a regulated
external supply of up to +100 VDC. The regulated external supply’s current must be
limited to 10 amps. See section 5.5.2 and Appendices B and E for further information.
If a regulated external power supply is used, two circuit board jumpers, TB1 and TB2,
have to be configured. The regulated external supply is hardwired to the Power
Supply module via the faceplate connector, using terminals P/S 2 and COM. Jumper
configuration and installation of the regulated external supply is described in section
5.5.2.
The Power Supply module also has a provision for connecting to an optional,
externally-mounted +28 VDC power supply via terminals P/S 1 and COM. This option
is normally not used. The Power Supply module must be configured for this option at
the factory.
Both the regulated external power supply and the internal +28 VDC supply are
referenced to the same negative point, DCCOM, accessible through the module’s
faceplate ("COM"). The +5 VDC output of the DC-to-DC converter has its own
negative reference point, +5VCOM. The power and ground signals are transmitted to
the PGA modules through the rack backplane.
In addition to powering the PGA modules, the Power Supply module also receives the
gate pulses from the DC Power Technology module in the PMI rack, via cables
connected to the two 15-pin D-shell connectors ("Input A" and "Input B") on its
faceplate. The gate signals are transmitted to the PGA modules through the rack
backplane.
The Power Supply module is fused by an external 8A line fuse on its faceplate and an
internal 1A fuse at the input to the DC-to-DC converter. The internal fuse is not user-
serviceable. A blown internal fuse indicates that the Power Supply module has failed
and must be replaced.
The temperature of the internal power supply is monitored by a thermostat. If the
temperature exceeds the rated operating level (see Appendix B), a set of normally
closed contacts is opened. The contacts are accessible to the user through faceplate
connectors TW1 and TW2.