Att 4-CPTS Evaluation Information.pdf

Design a Replacement ARSR4 Collector Power Supply Test Station (CPSTS) with functions similar to the current station with Interface Adapter Fixture, Test/Repair software and procedures to test the ARSR4 Collector/Preamp Module LRUs to specification

1.2.1 Functional Description. –

The CPSTS test set is a computer-operated diagnostic test tool designed to perform functional testing, fault diagnosis, and repair verification of the Collector Power Supply and Preamp Power Supply units used in the ARSR4 Radar. The CPSTS is also used to verify failures and troubleshoot units returned from the sites to the Depot as failed units.

1.2.3 Electrical Description-

The power distribution unit, located in the rear of the main console, serves as the main interface between the test set and 120/208 VAC, 60hz, 3 phase and the 120 VAC, 60hz, 1 phase utility power. The power distribution unit distributes this power to the internal instruments in the test set and protects the test set circuitry via integral circuit breakers.

A utility outlet is located on the power distribution unit on the rear of the console. This outlet is protected by an integral GFI circuit breaker. If this circuit breaker is tripped, the power to the entire test console will be disabled. If power cannot be applied to the test console, check to verify that this circuit breaker is properly reset before troubleshooting the console power problem. Test set power is activated and deactivated via a palm switch located on the patch panel interface module. A GPIB bus connector is provided to route the GPIB bus controller in from the personal computer to all GPIB controlled equipment in the test console. Signals from the individual test station hardware to the unit under test (UUT) are routed through a Virginia panel interface module providing a single connection point for all test equipment signals.

The UUT Interface Panel contains the main DC bus and AC input interface for the Collector/Preamp Power Supply UUTs. The Interface Panel also provides cool air and safety interlocks for the UUT. Cooling air is activated via the circuit breaker on the panel. Safety interlocks are incorporated so that the safety shields must be in place before the AC power source is activated.

The UUT Interface Panel also contains coaxial connections to allow the oscilloscope probes to be attached to the UUT with its covers removed and routed to the oscilloscope via jumper cables.

A capacitor load is installed behind the load assemblies to simulate the load encountered by the UUTs. The load is comprised of an array of one hundred 960 UF capacitors in parallel. Although bleeder resistors are connected across this capacitor to discharge the unit when power is turned off; care should be exercised when attempting removal or servicing of this assembly.

The computer/controller provides control of the CPSTS via the GPIB interface. The COTS GPIB interface card assemblies are located inside of the computer/controller.

Stimulus of the UUT and measurement of test resets are provided by the test software which in turn controls the test equipment via the GPIB. The computer/controller displays operator messages via the test equipment software to the operator using BORLAND C++.

The Test Program Set (TPS) interface test adapter (ITA) provides the monitor and control function for the UUT test, The ITA consists of metering for the UUT output voltage and current adjustments for the output voltage and current, adjustments for the output voltage and current, monitor test points, and power ON/OFF controls. An integral bleeder resistor is connected when power is turned off to ensure that the UUT output capacitors are discharged. The ITA also provides an interface cable to the UUT for both control and diagnostic testing. Polycarbonate safety shields are provided to protect the operator for inadvertently contacting the circuitry in the UUTs when troubleshooting with the UUT cover panel removed. These shields must be installed before input power will be provided to the UUT whether the UUT cover panels are on or off.

Offerors shall describe processes and equipment that the offeror will use to test the following subassemblies both independently and as an assembled unit.

Boards must be tested in situ. Reference TI 6340.26 Chapter 46 for schematic diagrams of each subassembly.

Submittals must provide evidence that the offeror has a clear understanding of the CPSTS test set as a computer-operated diagnostic test tool designed to perform functional testing, fault diagnosis, and repair verification of the Collector Power Supply and Preamp Power Supply units used in the ARSR4 Radar.

Collector Power Supply (CPS) The CPS converts ac to dc, provides energy storage for bridging of short-time power interruptions, and regulates voltage by controlling the restoration of charges to storage capacitor banks in the RF amplifiers. CPS operates as a feedback-controlled, on-off current source in supplying this voltage. The storage capacitor banks are in parallel with other CPSs to precisely restore and regulate the RF panel storage voltage between transmitter RF pulses. Samples of the dc storage voltages in the RF panels are averaged between the bus regulator and each CPS to obtain a single voltage sample. This sample is compared with a reference voltage in each CPS to control its operation. Primary power input is nominally 208 volts ac, three phase at 60 Hz. Collector power supply output is nominally 60 amperes (average) at a selected voltage between +28- and +40-volts dc. Timing and enabling signals come from the bus regulator.

Preamp Power Supply (PPS)

The PPS conditions power for the RF preamplifiers, converts ac to dc, provides energy storage in the PPS storage capacitor banks for bridging of short-time power interruptions, and supplies power to the preamplifier linear regulators. The PPS operates as a feedback-controlled, on-off current source in supplying this voltage. The storage capacitor banks precisely restore and regulate the PPS storage voltage. A sample of the dc storage voltage is compared with a reference voltage in the PPS to control its operation. Primary power input is nominally 208 volts ae, three phase at 60 Hertz. Preamplifier power supply output is nominally 50 amperes (average), at selected output voltage between +28-and +40-volts dc. Timing and enabling signals come from the bus regulator

CPS & PPS Sub-assembly Step- Start Control A1 A three-phase, full-wave bridge rectifier rectifies the input of 208 volts ac line-to-line (167 - 243 vac), three-phase primary power.

The rectifier output is +280 volts dc (+15 percent, -25 percent) and limits surge current during start-up. When this power line is initially energized, surge-limiting resistors, in series with the positive half-wave rectifiers, limit the surge current. Following a 40-millisecond delay after input power is applied, the resistors are bypassed by gated silicon-controlled rectifiers (SCRs) to remove current limiting.

CPS & PPS Sub-assembly Step-up Converter Control A2 The step-up converter control A2 circuit employs a current mode controller to regulate the output voltage across the energy storage capacitor banks at +350 volts dc by controlling on-drive duration to the up-converter FETs Q4, Q5 and Q6.

CPS & PPS Sub-assembly Control A31 The PPS control A31 is identical in operation to CPS control A31, except that PPS feedback control rather than CPS feedback control is processed. CPS control A31 is a central processing board for most of the timing, control, and BITE data signals involved in CPS operation. All CPS timing or clock signals are derived from the system 5.2 MHz clock input to CPS control A31

CPS & PPS Sub-assembly Switch Assembly A32 Switch assembly A32 is a forward converter with output to the primary of a three secondary output transformer.

CPS & PPS Sub-assembly +5-volt Regulator A33

The +5-volt regulator A33 consists of regulator integrated circuit UI with associated rectifying, filtering, and adjusting components.

CPS & PPS Sub-assembly -15-volt Regulator A34

The -15-volt regulator A34 consists of regulator integrated circuit UI with associated rectifying, filtering, and adjusting components.

CPS & PPS Sub-assembly +15/+12-volt Regulator A35

The +15/+12-volt regulator A35 consists of linear regulator integrated circuits UI and U2 with associated rectifying, filtering, and adjusting components.

CPS & PPS Sub-assembly House Supply Control A36

The house supply consists of three small regulators which provide low voltage power to the CPS and to the bus regulator. House control A36 provides witching drive to FETs Q1 and Q2 on switcher A32.

CPS & PPS Sub-assembly Switcher Control A37 through A41

(one resistor is different between the 2 LRUs) The switcher control senses current signal feedback sample from the switcher module and determines whether the power supply stays on-line or off-line.