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Installation requirements may vary, depending on the particularities of each aircraft, and this manual is intended as a guideline for that purpose. Although every effort has been made to keep it free of errors, some may occur. Department of Commerce. Location: Insertion Date By Rev. Insertion Date By Rev. Insertion Date By Retain this record in the front of this manual. Upon receipt of a revision, insert the revised pages in this manual, enter the revision number, date of insertion and initials on this record of revisions.
Circa Reissue March 31, Change February 3, Change August 29, Change January 24, Change March 13, Revision and Changes Revisions are used to correct major volumes of text or sections of a manual. Manuals at new revision incorporate all previous changes as well as any new changes or updates. Destroy old revisions when new revision is received. Changes are used to correct minor volumes of text or sections of a manual. A vertical line in the outer margins of the page indicates the portion of the text affected by the change.
Changes to illustrations other than diagrams and schematics are identified with a miniature pointing hand. Shading is used to highlight the area of diagrams and schematics containing a change. Those responsible for maintaining this publication should ensure that all previous changes have been received and incorporated.
Use the Publication Index located on the Avionics Systems, web site [www. Correct pin location on page , made corrections to Figure , added and corrected information for Capacity Testing starting on page , inserted new Figure , Corrected Figure , corrected test steps on page Updated Figure 7 pg.
In Repair section incorporated replacement instructions taken from SLB for battery cells and packs pg. Also consolidated repair section removing pages and In Assembly section added battery cell and pack replacement information pg. Added replacement statement to figure-item in IPL pg Revision B, Change 3 Added "Note" to various test procedures to ensure test switch was returned to normal.
Updated general information to match changes made to installation manual. Updated special tools and equipment information. Added Scotch Grip to consumable list replaces Vulcabond.
Added standoff insulators to assembly instructions. Corrected various typo's and error's to figure callouts. Revision B, Change 4 Changed Test and Fault Isolation section to more closely match procedures in other documentation.
Pg 5: Add G model to Figure 2. Pg 7: Add G model to Figure 4. Pg Add G model to Figure 7. Pg Add G model to Figure Pg thru Add G model. Pg Add G model to Figure and data in paragraph for installation kit. Add G model to Figure Pg thru , Pg Add G model to parts list. Made corrections to the following: Pg A: Updated export compliance statement.
Pg Correction to paragraph 4. Pg Reformatted paragraph 6 to match other publications. Corrected para. Pg Corrected Para. Corrected paragraph C. Pg thru Incorporate new part numbers added to IPL lists. Pg Corrected effectivity codes in item 5. List of Effective Pages Table of Contents Service Directives List List of Figures List of Symbols and Abbreviations Purpose of Equipment Physical Description Functional Description Continued Airworthiness MOD Status Environmental Test Qualifications Affiliated Equipment Charge and Discharge Performance General Battery and Cell Information Storage Time and Temperature Cell Current Discharge Time Cell Voltage Discharge Time Theory of Operation Power Input Heating Resistor Heater Control Over-Temperature Protection Battery Voltage Level Detection Disassembly Procedures It provides information needed to operate, maintain, and repair specific avionics equipment.
Block diagrams, schematic diagrams, and exploded views are used and referenced within this manual to present the information. An Illustrated Parts List is included to provide information for ordering replacement parts. Common system maintenance procedures are not presented in the interest of clarity.
The bestestablished shop and line practices should be used where no specific procedures are given. When direct current polarities are not defined with a given voltage value, the voltage is assumed to be positive with respect to ground.
Abbreviations and symbols used in this manual are defined in the List of Symbols and Abbreviations. All weights and measurements in the manual are in English units, unless otherwise stated. The manual is partitioned into sections, with tables, illustrations, and cross-references to information located in other sections.
Avionics Systems maintains this manual to insure correct and current information by means of revision notices, Service Letters and Service Bulletins.
Follow the instructions provided with revision notices concerning page replacement and notations to the Record of Changes page page i. See www. PS Emergency Power Supplies will exist in the field in various levels of modification, so a complete library to all the Service Bulletins that pertain to the PS at their latest revisions will be necessary. See Description section, chapter 6. Or contact Avionics Systems Customer Every effort has been made to insure that this list is complete.
Wire color symbols are not listed, as they are universal throughout the industry. General This manual provides description and theory of operation for Models PS A through G Emergency Power Supplies, part numbers through respectively.
Models A, C, and E use 2. Model Number Part Number A B C D E F G Purpose of Equipment The Model PS Emergency Power Supply is designed as a 24 Vdc nominal emergency power source for prolonging the operation of a connected standby attitude indicator when the aircraft main power buss has de-energized. The aircraft main power buss provides trickle charging to the PS while the aircraft performs normally.
The SI provides outputs of Vac or 5 Vac, Hz either at single or three phase alternating current. The SC provides direct current outputs of 2. Physical Description The PS Emergency Power Supply is fully enclosed unit, designed to easily mount onto an existing avionics shelf or the optional mounting rack Avionics Systems Model MTG part number , with models available with lightning surge protection.
Functional Description A. Power Input Aircraft 28 Vdc is connected to the emergency power buss through pin 10 of connector J1. The input is diode isolated from the internal batteries and circuits to prevent battery discharge in the event of a short circuit, or battery draw caused by low input from the aircraft main DC buss, such as at engine start.
The heating element, also, functions as a test load during the time the power supply is being tested aboard the aircraft. The heating control circuitry would then cease the heating-resistor's operation.
The heating circuit will remain inoperable until the temperature of sensor drops low enough to again permit heater operation. These indicate the state-of-charge of the stored power.
Refer to the Testing and Fault Isolation section of this manual for the following checks: Periodic Month Check Annual Capacity Testing A need for maintenance is indicated when unit fails the tests described above or functional monitoring as described below.
Functional monitoring is based upon the following: Observation of self-test failure notification applicable only when unit has self-test capability. Visual observation by the user. This unit has unlimited service life, where service life is defined as that point in time when repair is no longer economical.
This manual offers information in a manner that recognizes the various levels of modification at which a unit may exist in the field. All the schematics see Figures 8 through 13 and components in the Illustrated Parts Listing that have been affecting by the various modifications applied to PS Emergency Power Supplies are included in this manual.
SB A B C D Modify wiring to circumvent fuse for emergency operation. SB D Serial No's and higher. SB A B C D E F 11 11 6 6 4 3 To add warning instructions for proper care and maintenance of battery pack to prevent voiding warranty.
A2F2 Humidity Section 6. B Vibration Section 8. J Explosion Section 9. E Voltage Spikes Section 17 Cat. A Electromagnetic Compatibility Section 19 Cat. A Section 20 Cat. A Section 21 Cat. Height: 7. Width: 2. Model A, C, E - 8 lbs. Output: 24 Vdc nominal, 10 Amp max. Figure 4: Specifications 9. Affiliated Equipment A.
Charge and Discharge Performance A. This method will provide a long-term constant voltage to maintain the fully charged condition of the PS unit when not in service, without any other maintenance action. NOTE: The trickle charge method can be maintained indefinitely without damage to the charging batteries.
Charge time depends upon the batteries state-of-charge. Charging for 23 hours will essentially guarantee a full charge. The BC provides a constant charging current of either 0. When the unit being charged is within The remote test lamp must, at least, momentarily illuminate to indicate that the Power Supply is adequately charged. If no illumination of the remote test lamp is apparent for the period that switch is held, the Emergency Power Supply is incapable of providing power in an emergency.
Perform the check as listed in paragraph 5, Periodic Checks. Proceed to Fault Isolation Test, Step 7. Perform step 7. Cell Isolation Test if fuse is not blown. If possible, use pre-printed graft paper to create a record of the discharge period along the X- axis and voltage readings along the Y-axis.
Cell Isolation Test. This voltage must be greater than Return the unit into service or storage as required. If possible, use pre-printed graft paper to create a record of the discharge period along the X- axis and voltage reading along the Y-axis. Perform the Charging Procedures of Step 2. Performance Test This test is required before a unit can re-enter service after a repair action has been performed on the unit.
Recommended Test Equipment Figure provides a list of recommended test equipment needed to accomplish the test and charging requirements for the Model PS Emergency Power Supply.
NOTE: Equivalent equipment may be used for all listed items. See step 8. Performance Tests Procedures Before returning a PS Emergency Power Supply to operation the following performance test must be performed to insure operation of the unit according to original specifications. Record any results that fail to equal the required results listed in the Correct Results column. Use the Digital Voltmeter Figure , Item 2 independent leads to measure the voltage between J1 connector pin J and the chassis of the unit.
The voltage must be 25Vdc nominal. Check Transducer A1U1 ensure that it is not grounded. Repair if necessary before proceeding with calibration. Resistance must be Capacity testing may be performed by the following methods at the discretion of the technician.
For Models A, C and E record the output voltage at 20 minutes. A unit that fails to meet the minimum acceptable voltage will require service. A unit that meets the minimum acceptable voltage proceeds to the Recharging Procedures Paragraph. The internal load method uses the batteries heater blanket to discharge the batteries. Before conducting this test remove the power supply cover and place a small fan near the unit to dissipate heat.
The Automatic Discharge Method can only be used when a automatic constant-current battery analyzer is used. Models B, D, F and G will sustain a constant-current discharge of 3.
Models A, C and E will sustain a constant-current discharge of 1. This test procedure includes the calibration process to establish the correct voltage values that illuminate the monitor LED's. Pin numbers progress from pin 1 to pin 26 starting from the top of P3 connector when the CCA is viewed as oriented in Figure See Service Bulletin and Modification table, Figure 1.
Position switch S1 to OFF. Voltage must be In that case, back-up the adjustment CW about a full rotation. Raise the input voltage at J3 connector pin J slow and deliberate to avoid overshoot to Place Test Setup switch SW1 to position 2. Apply Digital Voltmeter lead to pin 24 TP 4.
The Digital Voltmeter must read 28 Vdc. Perform the Charging Procedures and Capacity Test Procedures as required to return the unit to service. Disassembly procedures are listed in descending order to allow for successive accessibility to sub- assemblies and components. These procedures are intended to cover most aspects of disassembly.
De-soldering of components and wires, and the replacement of items such as switches, fasteners, and other simple operations are not covered explicitly. Technicians working on avionics equipment of this type should have adequate knowledge of avionics shop practices before attempting any repairs. If wires are cut, do so in a manner that provides an adequate wire for re-connections. Disassemble the PS Emergency Power Supply only to the level necessary to repair the unit as revealed in the procedures of the Fault Isolation and Test section.
Any disassembly of the PS for repair or cleaning will require functional testing after re- assembly and before installation.
See the Testing and Fault Isolation section for functional test procedures and wiring diagrams. Place the PS on a stable, flat surface with appropriate lighting. Anticipate placing fasteners and other small components into containers to prevent loss. Use the Illustrated Parts List section to assist in the disassembly process. Save the Insulator Plates and discard cells. NOTE: De-solder, clip, or otherwise disconnect wires from terminals to the degree necessary to proceed with disassembly.
Remember to mark or tag wires and terminal to ensure for proper re-assembly. See Repair section for instructions and guidance for repair of those issues identified in the Performance Test of the Fault and Isolation section. See Assembly section for re-assembly instructions and guidance. The PS, like any avionics equipment, will accumulate dust and dirt during service.
Avionics Systems has taken precautions to allow cleaning the equipment with environmentally friendly solutions and chemicals. Procedures and suggested cleaning agents are described in this section. The outside surfaces and flat metal parts may be cleaned with a damp cloth containing a mild solution of ordinary household cleaner following manufacturer's instructions on cleaner container and water.
Dry the unit after cleaning before reinstallation and use. With exception to the circuit card assemblies CCAs , the internal surfaces of the assembly may be cleaned following the processes for external cleaning above. CCAs can be cleansed using Isopropyl Alcohol and a modified acid brush. Allow CCA to dry before use. Remove dust and dirt with a low-pressure jet of clean, dry air.
If necessary, use the brush depicted in Figure to loosen hardened dirt and embedded dust balls. This section provides avionics service personnel necessary guidance for inspections to the PS Emergency Power Supply, which will assist in identifying shortcomings that may result in failure of the unit operate.
Checks After Repair and During Re-assembly. Wiring insulated with Teflon should be checked closely for insulation cold- flowing and bare conductors. This phenomenon would be most evident at wire bends and places where wire bundles are secured or tied. Being able to see actual wire through the insulation does not necessarily mean the wire needs replacement. An insulation breakdown test will determine if replacement is warranted. Deficiencies found during inspection should be corrected when repairing a defective unit, or performed as a preventive maintenance measure to preclude future problems.
Repair defects in accordance with the Repair section of this manual. After assembly, perform unit performance test according to Testing and Fault Isolation section. See Figure 5 for storage lengths of non-ready conditions. General Repair of the PS Emergency Power Supply should be accomplished by a qualified technician at an authorized service center. Figure provides a list of consumable materials. When replacing cells within a pack the cells must be the same part number and vendor as the cells being replaced.
Avionics Systems recommends that when any pack has more than 4 defective cells, all 12 cells should be replaced.
To provide for best circuit board repair results, match these requirements in the CCA repair process. Consumable Materials This table lists the tools, fixtures, and consumable materials necessary to correctly assembly the PS- Emergency Power Supply. Those products listed that are considered chemical hazards are marked with a CH symbol. Material Safety Data Sheets should be on hand to determine the best means to safely handle these products. Prepare only enough coating to accomplish the task.
It is unnecessary and inadvisable to re-coat the entire CCA. Perform the tests cited in Testing and Fault Isolation section before returning unit into service or storage. Assembly procedures are listed in ascension order, starting at the lowest level of assembly. These procedures are intended to cover most aspects of assembly.
Soldering of components and wires, and the replacement of items such as switches, fasteners, and other simple operations are not covered explicitly. Testing procedures are found in the Testing and Fault Isolation section of this manual. If no wire marking was performed at disassembly, take time to identify wires and appropriate connection points before starting re-assembly process.
See Description and Operation section for Schematic Diagrams. Take special note that storage batteries contained in the PS are charged and capable of inflicting burns and shocks. Do not proceed with assembly without reading this entire section. Assembly Tools, Fixtures and Consumables This table lists the tools, fixtures, and consumable materials necessary to correctly assembly the PS- Emergency Power Supply.
Vulcabond V36 Figure Tools and Consumables Cont. Assembly Procedures A. For models C and D, de-solder and remove the pre-installed black negative wire from one of the cells. This cell now becomes BT For models E and F, de-solder and remove the pre-installed red positive wire from one of the cells. This cell now becomes BT1. For models C and D, solder the black negative wire that passes through the rear vertical chassis member access hole and is attached to Fuse Holder XF1 to the negative - terminal of cell BT Tie-Down Strap holes are numbered to correspond to cell ref.
Example: BT Cell solder pads are located adjacent to cell Tie-Down Strap holes. Pad polarity designated on board Example: BT7. Mount Washers and onto Screws and tighten. Perform those procedures listed in the Fault Isolation and Testing section before entering unit back into service. General The installation information provided is for typical install situations, not including information for specific aircraft. Additional information may be obtained from the original aircraft manufacturer.
Emergency Power Supply Location. The following steps provide general requirements for locating the Emergency Power Supply in an aircraft. The Emergency Power Supply provides limited direct-current power and Vac when in combination with Static Inverter Model SI to the aircraft emergency bus equipment in case of primary power failure. Therefore, the supply should be located in the general area of aircraft AC and DC busses.
Ensure that space requirements for the supply match space available for the installation being considered. Consider the relative distance to associated equipment. Keep connecting cables as short as possible. Check unit for physical damage that may have occurred during shipping and handling. For new-unit installation, the PS Battery Pack must be charged. See Testing and Fault Isolation section charging procedures. Units installed after a maintenance action must be tested in accordance with the Performance Test procedures listed in Testing and Fault Isolation section before installation.
For aircraft applications that require 26Vac output. Avionics Systems part number See Figure and The PS Emergency Power Supply contains internal fuses and circuit breakers to protect the supply against shorting conditions. Additional fuses or breakers may be required to protect aircraft wiring, as determined by the specific loads.
The required current-rating of any additional current protection is dependent on the load applied to the units connector J1 Pin Refer to the Typical Installation Interconnect Diagrams Figures or for additional information. See Specification table, Figure 4 for PS current output information. See Figure , Item 3 for suggested Transformer location. Test-switch circuitry of the previous PS setup must be altered as indicated below.
Test Test Lamp Lamp 6 6. This section lists those tools and equipment necessary to successfully repair, calibrate, and install the PS Emergency Power Supplies. In addition, normal avionics shop tools and equipment will be necessary for the repair and service of the unit.
The service issue concerned the position of J2 Connector for correct and successful pin contact to the connector of the Static Inverter SI, when used in conjunction with the PS Emergency Power Supply. The J2 Connector, see Figure and , position is irrelevant for aircraft applications that do not include the use of the SI Connector position can also be achieved using a ruler with decimal inch graduations.
The purpose of the Illustrated Parts List is to provide detailed illustrations and parts listings that assist in identification and location of component parts and assemblies for the PS Part Numbers through The illustrations and listing are arranged, also, to assist in the unit's assembly and disassembly.
NOTE: To insure accurate parts reciept, record the information on the Modification Plate, located on the front panel of the PS, and be prepared to provide that information when ordering parts.
The Numerical and Part Reference Designator Index tables are constructed to assist in utilizing the Detailed Part List when component identity is known. Contains a complete numerical-alpha listing of all part numbers appearing in the Detailed Parts List. Part Number Qty. This column lists all components by their equipment designator in alphanumeric sequence. This column lists the Detailed Parts List Item Number where all items having equipment designators can be found. The Detailed Parts List consists of illustrations and columnar parts listing of component parts for this equipment.
All assemblies, subassemblies, and parts that can be disassembled, repaired or replaced, and reassembled are included. The Detailed Parts List only lists and illustrates those parts attached by means other than welding or riveting, or other generally accepted means of permanent attachment.
Each illustration is assigned a figure number commencing with IPL Figure 1 and progressing sequentially from there. Alpha variants A thru Z will be assigned to figure numbers when necessary to add additional figures to show modification or configuration changes, or differences between units. This column reflects the assigned Item number of an illustration. Items listed but not shown on the illustration are identified with a dash - to the left of the item number.
Alpha variants A thru Z are assigned to existing item numbers when necessary to add items, to show configuration changes, or multiple sources for component parts. This column contains key and modifying words depicted within Goodrich Avionics Systems, Inc. Electrostatic discharge sensitive components are identified with bold letters ESDS. Quantities specified in this column are per item number.
The letters AR appearing in this column denote selection of parts on an As Required basis. Letters REF refer to an assembly completely assembled on a previous illustration. This column is used to establish parts compatibility with units or subassemblies that are essentially the same as far as color, marking methods, etc. A unique aspect of the sealed lead-acid cell is that the majority of the oxygen generated within the cell during an overcharge condition is recombined within the cell.
The quality of the lead grids used in construction minimize the evolution of hydrogen when overcharging occurs. Each cell has a self-resealing release valve designed to operate in the psi range. In normal use, the battery internal cell pressure never exceeds 20 psi. This means that in normal conditions the cell can be operated in a perfect vacuum and still have a sufficient safety margin, so that venting will not occur.
NOTE: Batteries should not be left in a discharged state under any circumstances. Cells should not be left connected to a load when in a discharged state or their ability to accept a charge will be impaired. The cell may develop shorts or chemical action will create water that will freeze at low temperatures and destroy the cell. All lead-acid cells and batteries produce gasses during charging. The amount and type of gas produced depends on state of charge, rate of charge, chemical composition of the electrolyte, and general condition of the battery.
Normally, gasses produced are recombined within the cells to form oxides and water. Venting occurs when excessive charge rates are placed on the battery or because of a defective cell s which subjects the remaining good cells to excessive charge rates.
Venting may also result from battery abuse or neglect. If the odor of rotten eggs becomes apparent in the cockpit, pull the aircraft Emergency Power Supply circuit breaker. The rotten egg odor is evidence that the lead-acid cells vent due to prolonged high rate overcharging. Although the possibility of toxic levels is extremely remote, the precaution of pulling the circuit breaker will prevent increased discomfort from the odor. Venting is an indication that the Power Supply in not controlling the charging process.
If venting occurs the factory recommends that the Power Supply be removed from the aircraft, tested according to the procedures listed in this manual, and to replace the defective cell s. If a ready condition is required of a power supply being stored, recharge batteries every 4 months for 1 hour at 28 to 30Vdc input.
Low storage temperatures on fully charged cells lessen the rate of self-discharge, thus increasing shelf life. On the other hand, high storage temperatures will accelerate self- discharge of the cells and storage under such conditions is not recommended. Refer to Figure 5. Figure 5: Cell Storage Time vs. Cell Current Discharge Time The rate of energy being withdrawn from a cell affects the amount of energy that can be obtained over time.
For example, at low current rates the energy in a cell lasts longer than at high current rates. The actual hours of service Amp-hours, or Ah from fully charged "D" or "X" cells can be determined from Figure 6 below.
Cell Voltage Discharge Time Figure 7 displays typical discharge curves at room temperature. Operation A. Battery Testing The majority of the components installed in the PS operate only during test functions.
NOTE: Test functions should be performed only with the main buss not providing power to the unit off or disconnected. That, in-turn, applies the battery voltage to the internal battery heater. While in the TEST mode, the batteries are placed under an approximate 7. This is not an ideal condition for battery state of charge tests and should not be considered valid.
If the remote test is being performed, the Remote Battery-Voltage Level Lamp will go on, provided the internally-loaded battery voltage level is greater than 24 Vdc. In case of low output capacity, these LED's will indicate which cell or cells have failed. The variation of brightness of the LED's does not indicate cell condition. Theory of Operation All the schematic diagrams are included in this section.
Any distinctions between drawing numbers and assembly part numbers that apply to the description of the Theory of Operation are highlighted. The majority of the components installed in the PS operate only during test functions. Various MOD level units exist in the field and are distinguished in this description by the various Battery Monitor CCA part numbers that may appear for repair. Diode A1CR1 isolates the internal batteries and circuits in case of a short circuit or low input from the aircraft main DC buss.
The circuit will remain in this state until the temperature of Thermal Resistor A1RT1 is low enough to again permit conduction. The voltage level detection system analyzes the battery voltage level at this time and will cause the appropriate LED's DS13 through DS16 to go on.
When a remote test is being performed, the Remote Battery-Voltage Level Lamp will go on, provided the loaded battery voltage level is greater than 24 Vdc. The brightness of the LED's may vary and does not indicate cell condition.
See Service Bulletin table Figure 1. General This section of the manual provides the following procedures; bench test, battery charging, periodic testing, performance tests and circuit card tests for the PS Emergency Power Supply. NOTE: Read these procedures thoroughly before proceeding with any testing. These instructions will offer reference to supporting Illustrated Parts List illustrations that will appear in parenthesis identifying figure and item number sample In addition, electronic components will include Reference Designator identification in parenthesis indicating the major assembly and component reference number that is listed or identified on the appropriate schematic sample A1R8.
Schematic drawings are located in the Description and Operation section. Venting occurs when excessive charge rates are placed on the battery or because of a defective cell s , which will subject the remaining good cells to excessive charge rates.
If venting occurs, the factory recommends that the Power Supply be removed from the aircraft, and tested to identify and replace defective cell s. NOTE: With proper maintenance and periodic testing, the likelihood of any battery developing undetected problems is very remote. If the remote test is being performed, the Remote Battery-Voltage Level Lamp will momentarily illuminate, provided the internally loaded battery voltage level is greater than 24Vdc. NOTE: After testing, it is possible that the lamp will not illuminate again until the batteries are recharged.
Any variation of brightness does not indicate cell condition. Charging Procedures A. Include a Diode 15 ADC min , Using the external power supply Figure , Item 1 , apply This method will provide a long-term constant voltage to maintain the fully charged condition of the PS unit when not in service, without any other maintenance action. NOTE: The trickle charge method can be maintained indefinitely without damage to the charging batteries. Charge time depends upon the batteries state-of-charge.
Charging for 23 hours will essentially guarantee a full charge. The BC provides a constant charging current of either 0. When the unit being charged is within The remote test lamp must, at least, momentarily illuminate to indicate that the Power Supply is adequately charged. If no illumination of the remote test lamp is apparent for the period that switch is held, the Emergency Power Supply is incapable of providing power in an emergency.
Perform the check as listed in paragraph 5, Periodic Checks. Proceed to Fault Isolation Test, Step 7. Perform step 7. Cell Isolation Test if fuse is not blown. If possible, use pre-printed graft paper to create a record of the discharge period along the X- axis and voltage readings along the Y-axis.
Cell Isolation Test. This voltage must be greater than Return the unit into service or storage as required. If possible, use pre-printed graft paper to create a record of the discharge period along the X- axis and voltage reading along the Y-axis. Perform the Charging Procedures of Step 2. Performance Test This test is required before a unit can re-enter service after a repair action has been performed on the unit. Recommended Test Equipment Figure provides a list of recommended test equipment needed to accomplish the test and charging requirements for the Model PS Emergency Power Supply.
NOTE: Equivalent equipment may be used for all listed items. See step 8. Performance Tests Procedures Before returning a PS Emergency Power Supply to operation the following performance test must be performed to insure operation of the unit according to original specifications.
Record any results that fail to equal the required results listed in the Correct Results column. The voltage must be 25Vdc nominal. Check Transducer A1U1 ensure that it is not grounded.
Repair if necessary before proceeding with calibration. Capacity testing may be performed by the following methods at the discretion of the technician. Internal Load Method The internal load method uses the batteries heater blanket to discharge the batteries.
Before conducting this test remove the power supply cover and place a small fan near the unit to dissipate heat. Automatic Discharge Method The Automatic Discharge Method can only be used when a automatic constant-current battery analyzer is used.
A unit that meets the minimum acceptable voltage proceeds to the Recharging Procedures Paragraph. Pin numbers progress from pin 1 to pin 26 starting from the top of P3 connector when the CCA is viewed as oriented in Figure See Service Bulletin and Modification table, Figure 1. Position switch S1 to OFF. Voltage must be In that case, back-up the adjustment CW about a full rotation.
Raise the input voltage at J3 connector pin J slow and deliberate to avoid overshoot to Place Test Setup switch SW1 to position 2. Apply Digital Voltmeter lead to pin 24 TP 4.
The Digital Voltmeter must read 28 Vdc. Perform the Charging Procedures and Capacity Test Procedures as required to return the unit to service. Disassembly procedures are listed in descending order to allow for successive accessibility to sub- assemblies and components.
These procedures are intended to cover most aspects of disassembly. De-soldering of components and wires, and the replacement of items such as switches, fasteners, and other simple operations are not covered explicitly.
Technicians working on avionics equipment of this type should have adequate knowledge of avionics shop practices before attempting any repairs. If wires are cut, do so in a manner that provides an adequate wire for re-connections. Disassemble the PS Emergency Power Supply only to the level necessary to repair the unit as revealed in the procedures of the Fault Isolation and Test section.
Any disassembly of the PS for repair or cleaning will require functional testing after re- assembly and before installation. See the Testing and Fault Isolation section for functional test procedures and wiring diagrams. Place the PS on a stable, flat surface with appropriate lighting. Anticipate placing fasteners and other small components into containers to prevent loss. Use the Illustrated Parts List section to assist in the disassembly process.
Disassembly Procedures A. Save the Insulator Plates and discard cells. Remember to mark or tag wires and terminal to ensure for proper re-assembly. Repair See Repair section for instructions and guidance for repair of those issues identified in the Performance Test of the Fault and Isolation section.
See Assembly section for re-assembly instructions and guidance. General The PS, like any avionics equipment, will accumulate dust and dirt during service. Avionics Systems has taken precautions to allow cleaning the equipment with environmentally friendly solutions and chemicals. Procedures and suggested cleaning agents are described in this section. The outside surfaces and flat metal parts may be cleaned with a damp cloth containing a mild solution of ordinary household cleaner following manufacturer's instructions on cleaner container and water.
Dry the unit after cleaning before reinstallation and use. NOTE: Water in connectors can be removed using low pressure compressed air. With exception to the circuit card assemblies CCAs , the internal surfaces of the assembly may be cleaned following the processes for external cleaning above.
CCAs can be cleansed using Isopropyl Alcohol and a modified acid brush.
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