PD_07WRGBZOENF7.doc - - 01-14-2009.doc

CAGE 98752

PD07WRGBZOENF7

Date: 25 June 2008

PURCHASE DESCRIPTION

250 kW Motor Generator Set

1.0 SCOPE

1.1 Coverage. This document covers the requirement for a 250kW Motor Generator Set, herein referred to as MG, which is used to convert 60 Hertz (Hz) power to 400 Hz power. The MG is used to supply 400 Hz ground power for various aircraft maintenance tasks on United States Air Force (USAF) E-3 and E-4 aircraft. The MG shall be the latest state of the art design and shall comply with the requirements of this document unless specified otherwise by the governing contract.

2.0 APPLICABLE DOCUMENTS

2.1. General. The documents listed in this section are specified in sections 3, 4, or 5 of this specification. This section does not include documents cited in other sections of this specification or recommended for additional information or as examples. While every effort has been made to ensure the completeness of this list, document users are cautioned that they must meet all specified requirements of documents cited in sections 3, 4, or 5 of this specification, whether or not they are listed.

2.2 Government documents.

2.2.1. Specifications, standards, and handbooks. The following specifications, standards, and handbooks of the exact revision listed below form a part of this specification to the extent specified herein.

FEDERAL STANDARDS

FED-STD-595C

Colors Used in Government Procurement

AMSC N/A

FSC 6125

Distribution Statement A. Approved for public release; distribution is unlimited

DEPARTMENT OF DEFENSE SPECIFICATIONS

MIL-DTL-0053030B Primer Coating, Epoxy, Water Reducible, Lead and Chromate Free

MIL-DTL-5541F

Chemical Conversion Coatings on Aluminum and Aluminum Alloys

MIL-PRF-23377JA2

Primer Coatings: Epoxy, High-Solids

MIL-PRF-26915D

Primer Coating, for Steel Surfaces

MIL-PRF-85285DA2

Coating: Polyurethane, Aircraft and Support Equipment

MS3452D

Connector, Receptacle, Electric, Box Mounting, Rear Release, Crimp Contact, AN Type with

DEPARTMENT OF DEFENSE STANDARDS

MIL-STD-130N

Identification Marking of U.S. Military Property

MIL-STD-209K

Lifting and Tiedown Provisions

MIL-STD-461F

Requirements for the Control of Electromagnetic Interference Characteristics of Subsystems and Equipment

MIL-STD-704F

Aircraft Electrical Power Characteristics

MIL-STD-705C

Generator Sets, Engine Driven Methods of Tests and Instructions

MIL-STD-810FC3

Environmental Engineering Considerations and Laboratory Tests

MIL-STD-882D

Standard Practice for System Safety

MIL-STD-889BC3

Dissimilar Metals

MIL-STD-1472FC1

Human Engineering

(Copies of these documents are available online at http://assist.daps.dla.mil/quicksearch/ or www.dodssp.daps.mil or from the Standardization Document Order Desk, 700 Robbins Avenue, Building 4D, Philadelphia, PA 19111-5094.)

2.3. Non-government documents. The following documents of the exact revision listed below form a part of this document to the extent specified herein.

American National Standards Institute (ANSI)

ANSI C2

2007 National Electrical Safety Code

(Application for copies should be addressed to ANSI, 1819 L St. NW, 6th Floor, Washington DC 20036, www.ansi.org.)

Institute of Electrical and Electronics Engineers, INC (IEEE)

IEEE C62.41

1991 IEEE Recommended Practice on Surge Voltages in Low-

Voltage AC Power Circuits

(Application for copies should be addressed to IEEE, 445 Hoes Lane, Piscataway, NJ 08854, www.ieee.org or electronically available at: http://www.ieee.org/portal/innovate/products/standard/ieee_choice.html.)

J and B Aviation Services

TG8819-150NJ

300 Amp Cable Assembly with RVS

TG8818-150NJ

300 Amp cable Assembly without RVS

(Application for additional information should be addressed to J&B Aviation Services, 907 Cotting Lane, Suite A, Vacaville, CA 95688, www.jandbaviation.com.)

National Electrical Manufacturers Association (NEMA)

MG-1

2007 Motors and Generators

MG-2

2001 Safety Standard for Construction and Guide for Selection, Installation, and Use of Electric Motors

WD 6

2002 Wiring Devices-Dimensional Specifications

2003 Enclosure for Electrical Equipment: 1000 Volt Maximum

(Applications for copies should be addressed to NEMA, 1300 North 17th Street, Suite 1847, Rosslyn, VA 22209, www.nema.org.)

National Fire Protection Association (NFPA)

NFPA 70

2008 National Electric Code

(Application for copies should be addressed to NFPA, Batterymarch Park, Quincy, MA 02169-7471, www.nfpa.org.)

Society of Automotive Engineers (SAE)

AS 90362

2002 Connector, Receptacle, External Electric Power, Aircraft, 115/200 Volt, 400 Hertz

(Application for copies should be addressed to SAE, Inc., 400 Commonwealth Drive, Warrendale, PA 15096, www.sae.org.)

Underwriters Laboratories, INC. (UL)

UL 489

2006 Molded Case Circuit Breakers & Circuit Breaker Enclosures

(Application for copies should be addressed to UL, 333 Pfingston Rd, Northbrook, IL 60062-2096, www.ul.com.)

2.4. Order of precedence. In the event of a conflict between the text of this document and the references cited herein, the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained.

3.0 REQUIREMENTS

3.1 First article. When specified (see 6.2), one first article MG shall be subjected to first article verification in accordance with 4.1.

3.1.1 General. The MG shall be a stand alone, weatherproof, self-contained unit capable of converting 60 Hz power to 400 Hz power. Specifically, the MG shall be capable of providing three phase 115/200 volts alternating current (VAC), 400 Hz, rated to continuously provide (100% duty cycle) 250 kW/312kVA of electrical power. The MG shall be configured with an on-board output power distribution system featuring four aircraft style cables and two aircraft style receptacles. The MG shall be constructed of modular and easily replaceable subassemblies and components wherever possible. The MG enclosure shall be suitable for full time outdoor use and be skid mounted with provision for forklifting. The MG shall be self air-cooled by the use of its own fan and be suitable for use in a wide range of indoor and outdoor environmental conditions. The enclosure shall have doors to provide access for maintenance, repair, and replacement of modular components and subassemblies. The MG shall have Built-In-Test-Equipment functions to continuously monitor, control, and provide diagnostics. Components of the MG shall be UL recognized or listed whenever possible. Additional features and capabilities shall be permitted unless otherwise prohibited by this document.

3.1.2 Modes of operation. This generator set shall be used in various operational modes and configurations, dependant upon type of service and type of aircraft receiving service. In all operational modes the criteria set forth herein shall be met. See 3.4 herein for additional details of the on-board 400 Hz distribution system, the "Master" cable, and the line drop compensation circuit.

a. Configuration 1. Configuration 1 is described as four 150 foot long aircraft style cables installed on the MG for use in delivering 400 Hz output power.

Mode 1: Single active output cable with a maximum steady state aircraft load of approximately 260 amps. In this mode of operation a single cable will be utilized to provide front end power (lights, pumps, blowers, etc.) to the aircraft. In a typical installation this will be the number 1 or "Master" cable equipped with remote sensing capabilities.

Mode 2: Two (2) active output cables with a maximum steady state aircraft load of approximately 520 amps. In this mode of operation one cable (usually the number 1 or "Master" cable) will be utilized to provide front end power (lights, pumps, blowers, etc.) to the aircraft and the other cable will be used to provide power for other aircraft loads. The load side 400 Hz power may or may not be drawn from a unitized buss. The MG is expected to only regulate to the manual settings or to the input provided by the remote sense function from the "Master" cable.

Mode 3: Three (3) active output cables with a maximum steady state aircraft load of approximately 780 amps. In this mode of operation one cable (usually the number 1 or "Master" cable) will be utilized to provide front end power (lights, pumps, blowers, etc.) to the aircraft and the other cables will be used to provide power for other aircraft loads. The load side 400 Hz power may or may not be drawn from a unitized buss. The MG is expected to only regulate to the manual settings or to the input provided by the remote sense function from the "Master" cable.

Mode 4: Four (4) active output cables with a maximum steady state aircraft load of approximately 903 amps. In this mode of operation one cable (usually the number 1 or "Master" cable) will be utilized to provide front end power (lights, pumps, blowers, etc.) to the aircraft and the other cables will be used to provide power for other aircraft loads. The load side 400 Hz power may or may not be drawn from a unitized buss. The MG is expected to only regulate to the manual settings or to the input provided by the remote sense function from the "Master" cable.

b. Configuration 2. Configuration 2 is described as two 175 foot long dual plug aircraft style cables installed on the MG for use in delivering 400 Hz output power.

Mode 1: A single active dual plug output cable with a maximum steady state aircraft load of approximately 260 amps. In this mode of operation a single cable will be utilized to provide front end power (lights, pumps, blowers, etc.) to the aircraft. In a typical installation this will be the number 1 or "Master" cable equipped with remote sensing capabilities. (Remote sensing capability shall be provided through use of an external to receptacle cannon type plug on number 1 or "Master" cable.) In this mode of operation none of the four standard type aircraft cables will be in use or installed.

Mode 2: Two (2) active dual plug output cables with a maximum steady state aircraft load of approximately 520 amps. In this mode of operation one cable (usually the number 1 or "Master" cable) will be utilized to provide front end power (lights, pumps, blowers, etc.) to the aircraft and the other cable will be used to provide power for other aircraft loads. The load side 400 Hz power may or may not be drawn from a unitized buss. The MG is expected to only regulate to the manual settings or to the input provided by the remote sense function. Remote sensing capability shall be provided through use of an external to receptacle cannon type plug on number 1 or "Master" cable. In this mode of operation none of the four standard type aircraft cables will be in use or installed.

3.2 Motor/generator design. The motor and generator shall each be of a brushless design; excitation shall be supplied from a brushless exciter as well. Single or double bearing type machines are acceptable. Temperature rise of each shall be in accordance with limits set forth in NEMA MG-1 for Class F or H insulation; vacuum impregnated epoxy resin or similar process shall be used to ensure long-term insulation effectiveness. Temperature rise of bearings shall not exceed 90 degrees Fahrenheit. Insulation resistance shall not be less than 2 mega-ohms in an ambient temperature of 77 degrees Fahrenheit. The motor and generator shall be capable of operation at 125% rated speed for fifteen minutes without electrical or mechanical damage. The windings shall be equipped with heating provisions to prevent premature insulation breakdown during periods of inactivity. Both machines shall be of drip-proof guarded type and meet all applicable requirements of NEMA MG1 and MG2. Electrical windings shall have the following dielectric strength (withstand the following 400 or 60 Hz voltages applied for one minute):

A. Armature, 1832 volts between phase windings and 1480 volts between phase windings and ground.

B. Field and Exciter Windings, 10 times ceiling voltage but shall not be less than 1500 or more than 3500 volts between windings and ground.

C. Windings Energized By DC Voltages (Control, Starting, Sharing Systems), 500 volts between windings and ground; windings shall be insulated to Class F or H standards using a void free 100% solids epoxy vacuum pressure impregnation process.

D. All others, twice rated voltage plus 1000 volts applied between windings and ground and between windings when applicable.

The MG set motor, generator, and excitation systems shall be capable of withstanding a 10 second duration single phase line to neutral, single phase line to line, and symmetrical 3 phase short while operating at rated load. Reduction in dielectric strength shall not be allowed. Short circuit current is defined as not less than 300 percent of rated full load current. The MG set shall be configured such that neither symmetrical nor asymmetrical faults will cause damage.

3.3 Input power. The MG shall operate with 3-phase, 4-wire, grounded, alternating current (AC) delta or wye configured power input.

3.3.1 Input voltage and frequency. The MG shall be capable of accepting 277/480 (( 10%) VAC at 60 (( 5%) Hz. Note: it is recognized that the output frequency will track the input frequency by a given ratio and that severe deviations from the nominal 60 Hz input frequency will also cause deviations in the nominal 400 Hz output frequency.

3.3.2 Input phase sequence. The MG shall accept positive (A-B-C) input power phase sequence.

3.3.3 Input power factor. The MG shall accept input power with a power factor of 0.8 to 1.0 lagging and 1.0 to 0.95 leading.

3.3.4 Starting current. The starting current (inrush) of the MG shall not exceed 90% of the input current required by the unit when it is operated at full load.

3.3.5 Input surge protection. The MG shall be capable of sustaining an input surge described in and tested in accordance with IEEE C62.41, location category B, and continue to operate with no alarms within the specified tolerance.

3.3.6 Input current distortion. The total harmonic distortion with normal input voltage while providing rated output shall not exceed 3%.

3.3.7 No-load input losses. The MG shall have no-load input losses no greater than 10% of the total output rating.

3.4 Output AC electrical power. All aircraft AC power shall be derived from the generator itself and shall meet the performance requirements listed below. All ratings defined in the following subparagraphs are applicable over the entire generator speed range and environmental conditions specified herein.

3.4.1 AC output voltage and frequency. The MG output voltage shall be three phase, 115/200 VAC, wye configured with a grounded neutral, and the MG output frequency shall be 400 Hz regulated to ± 1% at all loads. The continuous rated output voltage shall be 115 VAC (L-N) regulated to (1% at all settings from zero to full load at the cable head. The MG shall also provide enough adjustability to provide a regulated, continuous supply of 117.5 volts (L-N) VAC at the cable head. This adjustment shall be made separately from the normal operator interface, either through locked menu or inside the enclosure, or similar means. Note: the MG shall be pre-set to deliver 115 VAC at the cable head. The DC component in the output voltage shall not exceed (0.1 volts and the crest factor shall be 1.31 to 1.51. The MG shall operate as specified with a delta or wye configured load.

3.4.2 Output power rating. The MG shall meet the requirements set forth herein and any additional requirements contained in MIL-STD-704F. The MG shall have a continuous output power rating of 250kW/312kVA at the aircraft external power receptacle(s); the MG shall be capable of providing continuous power into a load with a power factor between 0.95 leading and 0.8 lagging. All applicable tolerances stated herein and in MIL-STD-704F shall be met with the output voltage preset to 115 VAC (L-N) at the cable head under all load conditions including transients.

3.4.3 Output phase sequence. The phase sequence of the MG output voltage shall be a positive sequence of A-B-C (AB-BC-CA).

3.4.4 Phase balance. The output voltage for each phase shall be balanced (within 1%) while the MG is operating at full load (with 0.8 power factor), no load, or any load in between. For a three phase unbalanced load not exceeding 15% (see 3.4.5 herein) the load unbalance shall not exceed 3.33% of the total three phase load.

3.4.5 Unbalanced loads. The MG shall be capable of supplying a 15% maximum unbalanced load. The unbalanced load of 15% shall be defined as one the three phases at its full load condition and the remaining two phases at 85% of their full load condition. Under this condition the difference between any of the three phase to neutral voltages shall be no greater than 3.5%.

3.4.6 Phase angle regulation. The displacement angle between adjacent voltages shall be 120 degrees (( 2 degrees) for the balanced load and shall be 120 degrees (( 4 degrees) for the three phase 15 percent unbalanced load.

3.4.7 Amplitude modulation. The MG (voltage) amplitude modulation shall not exceed 1% for no load to full load conditions.

3.4.8 Frequency stability. The MG frequency regulation shall be independent of the load changes. The frequency stability of the MG shall be at a minimum ( 1% (400 Hz) for all load conditions.

3.4.9 Output power distribution configuration. The MG shall be designed for use with two different output configurations: Configuration 1--four normal aircraft style cables with terminals on one end and a receptacle on the other end (see 3.1.2 herein); Configuration 2--two dual plug aircraft style cables with plugs on each end (see 3.1.2 herein). The distribution system shall be based on a four cable design with outputs one and two also having independently controllable 400 Hz aircraft style receptacles. (Receptacles one and two shall be interlocked with cables one and two to prevent power application to a cable and receptacle at the same time.) The contactors and associated outputs shall be numbered 1 through 4 with number 1 serving as the “Master” (receptacle 1 shall also serve as the "Master"). The MG shall be equipped with a minimum of four, maximum of six (dependent upon contractor's design) individually controlled, minimum 300 amp rated, 115/200 VAC contactors each capable of meeting the requirements listed herein. Each of the contactors shall be individually protected for overcurrent. Each contactor shall have its own safety control circuitry (E/F controls, see 3.4.18 herein). The “Master” outputs shall be used for making the automatic line drop compensation (ALDC) adjustments (see 3.4.10 herein) and the remote sensing measurements (see 3.4.11 herein). The distribution system shall be designed so that there are two cables on each side of the generator set (one cable at each corner--both of the aircraft receptacles shall be located on the same side of the unit). All cable entry/exit points shall be designed with strain relief devices to prevent damage in the deployed or stowed position.

3.4.10 Line drop compensation. The MG shall provide both a manual adjustment and an automatic adjustment to compensate for line drop loses in the output power cables. The MG shall have a switch to manually select the compensation method used; both the selector switch and the manual adjustment device shall be located away from the normal operator interface either via locked menu, cabinet door, or similar means. The line drop compensation circuit shall provide full voltage adjustment over the entire range of generator set operating voltage. While in the ALDC mode of operation the MG shall sense the output voltage in two selectable locations, local and remote (see 3.4.11 herein). The MG shall provide a minimum of 10% voltage adjustment through both manual and automatic line drop compensation. Note: installation Configuration 2 using the two aircraft receptacles and dual plug cables described herein as the means of output utilize 175 foot single jacket 115 VAC 300 amp rated cables; the line drop compensation circuit shall provide sufficient adjustment range to overcome line losses in this cable at a full load. (See Appendix B herein for additional details of the 175 foot cable assembly.) While operating in the ALDC mode of operation, utilizing the remote sense function of 3.4.11 herein, the MG shall provide the specified voltage as required by MIL-STD-704F and herein at the cable head(s) of both the 150 foot and 175 foot cables referenced herein. All active output devices shall be increased or decreased by the same amount regardless or manual or automatic line drop compensation adjustment, i.e. there shall be no independent compensation for each active output.

3.4.11 Sensing. The MG shall be equipped to operate with local voltage sensing and remote voltage sensing (RVS) while in the ALDC mode of operation. In local sensing mode the output voltage shall be sensed at the output buss or terminal stud of the "Master" cable, "Master" receptacle, or main 400 Hz buss of the MG, dependent upon the contractor’s design. In remote sense mode the output voltage shall be sensed at the load end cable head of the "Master" cable (regardless of whether the standard terminal ended cable is in use or the dual ended cable is utilized with the "Master" receptacle). The local/remote selector switch shall be located away from the normal operator interface via locked menu, cabinet door, or other similar means. When operating in remote sensing mode the MG shall automatically revert to local sense mode if a break occurs in the sensing wires. Note that current sensing is also acceptable method of providing ALDC. If current sense is used in the contractors design only a remote sense function is needed but an “ON” and “OFF” device shall be provided for the ALDC.

3.4.12 Output transient recovery. The MG transient output voltage recovery shall be in accordance with MIL-STD-704F Figure 3 and the output frequency transient recovery shall be in accordance with MIL-STD-704F Figure 5.

3.4.13 AC overload/overcurrent. The MG shall be designed with thermal overload capability of at least 125 percent full load rated current for 10 minutes and 200 percent full load rated current for 10 seconds. The MG shall be equipped with adjustable trip points permitting a range of overload settings at 115 VAC (L-N). If the total output current on the internal MG 400 Hz buss exceeds 125% (+/- 2%) on any phase for more than 30 seconds, overload control circuitry shall open all active output contactors. If the output current of any individual contactor exceeds 125% (+/- 5%) of the steady state limit (see 3.3.14 herein) on any phase for more than 30 seconds or exceeds 250% (+/- 2%) of the steady state limit (see 3.3.14 herein) on any phase for more than 1 second, the MG overload control circuitry shall open the overloaded output contactor. As part of any overload condition the MG overload system shall be designed to prevent any remaining active output contactors from carrying the load of the deactivated contactor if the total load exceeds the steady state limit of the remaining active contactors or the total capacity of the MG is exceeded. Overload capacity for the individual contactors and the total output capacity of the MG shall be based on the inverse time delay curve principle dependant upon motor and generator design with the limits stated above being particular points of interest on the curve.

3.4.14 Output contactor load adjustment. Due to the varied in-use configuration requirements of the MG, each output contactor shall be equipped with individually adjustable load protection. The MG shall be equipped with a means to adjust the steady state current limit for each output contactor in 5 amp increments (via a locked menu or inside enclosure-away from normal operator interface) from a preset factory level of 225 amps to a high level of 260 amps. (Note: in routine use each normally active contactor, dependent upon installation configuration, will be set to the same level.) In configurations set to provide more that 225 amps steady state on all contactors, four contactors would not be expected to be in use simultaneously.

3.4.15 Short circuit. The MG shall be protected against a short circuit across any of the output AC lines and shall disconnect power from the load buss within 25 milliseconds in the event of a short circuit in any output phase.

3.4.16 Total harmonic distortion (THD). The THD in the output voltage for the MG, regardless of ancillary power supplies, motors, etc. on the generator set that may be operating, shall be as follows:

a. Balanced Load Condition: From no load to full load, the Root Mean Square (RMS) sum of all THD components in the output voltage waveform line-to-line and line-to-neutral shall not exceed 3% of the RMS value of the rated voltage. Maximum single harmonic distortion shall not exceed 2% RMS of the fundamental at the nominal voltage under the above listed conditions. Additionally, there shall be no spikes or notches in the output waveforms.

b. Unbalanced Load Condition: THD shall not exceed 4% (RMS) line-to-neutral with a 15% unbalanced load applied.

3.4.17. Efficiency. The minimum efficiency of the MG shall be at least 75% at half load condition and 85% at full load condition.

3.4.18 28 VDC aircraft interlock E/F circuit. The MG shall have selector switches (located on the control panel in the vicinity of the output contactor control devices) labeled as "MG LOOP-BYPASS-AIRCRAFT LOOP" to control the E-F pin interlock circuit for each individual output device. Note: two switches with one labeled as “GENERATOR POWER-AIRCRAFT POWER” and the other labeled as “LOADBANK” are also acceptable for each individual output device. The MG shall contain terminal block points for the connection of 12 AWG wires from the aircraft cable assemblies for the interlock circuit. The MG E-F interlock circuit shall not be sensitive to the polarity of the DC current flowing to and from the aircraft. When the DC current goes to 0, for any reason, the output contactor in operation shall open within 25 milliseconds. The MG shall accept an unfiltered half-wave rectified 28 VDC signal, but an intermittent signal shall not be permitted. For descriptive purposes below the “28 VDC signal” below is the nominal steady state value, actual values may range from 16 to 32 volts with 28 +2/-4 volts being the most common steady state values. In “AIRCRAFT LOOP” mode, before the interlock loop is complete, the voltage sent to the MG may be a very choppy sine-wave like waveform approaching 60 volts. The MG shall be capable of receiving and providing at least 5 amps of current continuous, and as much as 10 amps to close the E/F pin relay contacts.

In the Aircraft Loop mode, the MG shall close the output contactor for a period of 4 to 6 seconds at start up. The MG shall receive a 28 VDC signal from the aircraft on the F pin and loop it back to the aircraft via the E pin. This loop shall be monitored by the MG to determine if a 16 to 32 VDC signal is present. When present, the output contactor shall remain closed. When this signal is not present or drops out the output contactor shall open (within 25 milliseconds).

In the Bypass mode the E-F pins may be connected together but are not monitored or grounded. The E-F pin circuit is not used to control the output contactor. Any changes required to operate in the Bypass mode shall be automatically implemented.

In the MG Loop mode, the MG shall close the output contactor for a period of 4 to 6 seconds at start up. The MG shall provide a filtered and regulated 28 VDC signal to the aircraft via pin E. If the 28VDC signal is looped back on the F pin, then the output contactor shall remain closed. If the voltage is not present on pin F, then the output contactor shall open (within 25 milliseconds).

3.4.19 AC output power cables. Each MG shall be shipped from the factory with four cables featuring: 150 foot length; 300 amp three phase 400 Hz rating for 115/200 VAC aircraft power; balanced conductor configuration with 2/0 AWG center neutral conductor, equi-distance spaced #2 AWG phase conductors, and six triad configured #18 AWG control conductors; single neoprene insulation jacket to encase all conductors; one molded cable head with molded strain relief and high visibility yellow Thermguard replaceable nose to mate with AS90362 receptacles; appropriately sized cable lugs to mate with the connections on the MG set. The master cable shall also feature sensing wires for the remote voltage sensing function. The interfacing cables shall be part number TG8819-150NJ (with RVS) CAGE 0SMN2, or TG8818-150NJ (without RVS) CAGE 0SMN2, or equivalent; note that the Government shall have final approval authority on cable equivalency. See 6.3 c. herein for additional details of the interfacing cable assemblies.

3.4.20 AC output power receptacles. The MG shall be equipped with two (2) independently controllable aircraft style receptacles for use with the output power distribution system operational configuration 2: dual plug cables. The two auxiliary three phase 115/200 VAC, 400 Hz SAE AS 90362-4 aircraft style receptacles shall be rated to provide 260 amps continuously. The receptacles shall be used with 175 foot single jacket 115 (L-N) VAC 300 amp rated capacity cables defined as P/N JB8819-175SNJRM, CAGE OSMN2 (note: these cables are not to be supplied with the MG). See Appendix B herein for additional details of the 175 foot cable assembly. The receptacles shall be located in the vicinity of AC output power cables one and two, be accessible from the exterior of the unit, and shall be weather-protected by the use of a hinged door or cover. High voltage caution or warning information shall be affixed to the door or cover of the auxiliary receptacle(s). The receptacles shall be interlocked with cables one and two to preclude inadvertent simultaneous power application to both cables one and two and receptacles one and two. The receptacles shall be powered by the main MG 400 Hz bus and E/F safety interlock circuitry shall be retained. In addition, receptacle one, or the "Master" receptacle shall be fitted with an MS3452W18-4P cannon plug, located adjacent to the receptacle, for use in receiving the remote sensing signals from the dual ended cable.

3.4.21 Crowbar. In addition to the transient voltage levels of 3.4.12 herein and the overload conditions of 3.4.13 herein, the MG shall also be capable of providing power during a radar crowbar event. The particular operational details of this event are: Configuration 1 (all four legs of power active) with an initial load of 75-100 kVA (approximately 220-280 amps RMS) of pumps, blowers, lights etc. running on 115 VAC compensated cables. Application of the radar adds another 140 kVA load to the existing 100 kVA load. When a crowbar occurs, the 140 kVA radar load (approximately 400 amps RMS) becomes a 1330 amp RMS load for approximately 20 milliseconds (ms). (The total load may increase from approximately 680 amps RMS to 1610 amps RMS for up to 20 ms.) Ground power transient voltages experienced at the aircraft end of the power output cables shall be in accordance with Figure 1. Curve A applies to transients experienced during normal operations and curve B applies to transients experienced in the event of radar crowbar. In other words, if a crowbar occurs, the ground power system shall not allow the system voltage at the aircraft interface to drop below 93.5 volts (L-N, RMS), nor shall the reduced voltage (not lower than 93.5 volts, for 20 milliseconds) deactivate the MG output power.

Figure 1. Crowbar Limits.

3.5. Control and monitoring. The MG shall be designed to control, indicate, monitor, alarm, and display the functions listed below. All switches and controls shall be located together in a common control panel unless otherwise noted. The MG control panel shall be arranged so that groups of controls are placed in order of similarity. There shall be as a minimum: Systems Controls, Input (motor) Instruments and Controls, Output Power Instruments and Controls, and Fault System Instruments and Controls groupings. Each group of controls shall be clearly marked or delineated to avoid confusion on the groupings. Note: meters may be any type of digital or analog but any selected meter shall comply with the accuracy standards herein and comply with the operational and non-operational environmental requirements stated herein. The control panel shall be vertically hinged so that components comprising the panel and components behind the panel may be able to be serviced. Multi-function type displays are not expressly prohibited but all parameters for each operation shall be displayed simultaneously (i.e. AC output power display: all parameters listed herein such as volts, amps, frequency shall be displayed simultaneously without the need to toggle between individual screens or menus). Individual type meters for electrical power parameters shall be at least 3.5 inches in outside diameter. All "needle" or "sweep" type gauges shall display the increase level in the clockwise direction. All displays, controls, and switches shall be of a design such that they can be operated during the use of artic clothing/mittens or Mission-Oriented Protective Posture (MOPP) Level 4 Chemical Warfare Gear including chemical, biological, and radiological clothing/rubber gloves.

3.5.1 System controls.

3.5.1.1 Illumination. The MG control panel shall be arranged and adequately illuminated so that all controls, switches, and displays may be operated in any ambient lighting condition to include bright sunlight and darkness. Panel illumination shall be able to be controlled via an on/off switch or menu. All displays, light emitting diodes LEDs, meters, etc. shall be viewable in bright sunlight conditions as typically encountered in an outdoor, flightline, or ramp environment.

3.5.1.2 Emergency stop push-button. An emergency stop push-button shall be provided on the control panel to immediately open the output contactor, turn off the control functions, and stop the motor; activation of the emergency stop device shall immediately turn off the MG and completely disconnect all input power from the MG cabinet and control system.

3.5.1.3 Built-in-test-equipment. The MG shall be provided with Built-in-Test-Equipment (BITE) which will monitor both primary motor and generator circuits and protective circuits for the unit. When a malfunction is detected, the BITE shall inhibit the MG from operation and activate the fault indication system. The BITE shall perform a complete system self-test prior to start-up through the “MASTER” switch. An illuminated “POWER ON” indicator shall indicate all systems are functional and input power is available to the motor and control circuits. The BITE shall detect malfunctions that caused the MG to fail to operate under its normal conditions. All the controls needed to operate or perform manual functions for the Built-in-Test-Equipment features shall be included on the control panel.

3.5.1.4 Verification board. The MG shall be equipped with a verification board(s) or similar device through the use of software to provide access to high voltage/high current test points or non-easily accessible signals for measurements when routine maintenance or adjustments are needed on the MG. The device(s) do not have to be located on the control panel.

3.5.2 Input (motor) instruments and controls.

3.5.2.1. Input circuit breaker/contactor. The MG shall be equipped with a manual device for opening and closing the input. The controlling handle shall be accessible from the exterior of the unit and shall be located on the control panel. Circuit breakers used for this purpose shall be fully rated heavy duty three pole breakers in accordance with UL 489 and feature a minimum fault current rating of 45,000 amps at 480 volts. If a contactor is used to control the input it must be capable of being manually opened even when no power is provided to the MG set. A lamp or LED to indicate that the MG input circuit breaker/contactor is “ON” shall be provided on the control panel.

3.5.2.2 Master switch. The MG shall be equipped with a switch that will apply and remove input (facility 60 Hz) power to the MG control systems, panel lights, and fault circuits. Placing the “MASTER” switch in the “ON” position shall not start the motor. The contractor may combine the function of the master switch with the input control device but in either case an indicator shall be provided to denote that power is applied to the MG and in no instance shall closing the input breaker start the motor.

3.5.2.3 Start and stop push-button. A start push-button shall be provided on the control panel to operate the motor operations of the MG; it shall not close the output control device. A stop push-button shall also be provided to shut off the motor operations of the MG.

3.5.2.4 Motor on indicator. A lamp or LED to indicate that the MG motor is running shall be provided on the control panel.

3.5.2.5 Elapsed time meter. An elapsed time meter to show the operating hours of the MG shall be provided on the control panel. The range of the elapsed time meter shall be 99,999 Hours.

3.5.3 Output system instruments and controls.

3.5.3.1 Output contactors. The MG shall be equipped with devices for opening and closing the AC outputs; each 400 Hz output device shall have independent on and off controls. All electrical output control devices shall be located on the control panel of the MG. All devices operating at 400 Hz shall be derated for 400 Hz operation. The 400 Hz AC contactors shall be interlocked with their respective 28 VDC safety interlock circuits (see 3.4.18 herein). The contactors shall be tripped by MG abnormal alarm conditions; power shall be removed from the output contactors within 25 milliseconds after receiving a stop command, fault command, or loss of interlock. The actual output contactors do not have to be located on the control panel but the devices to operate the contactors shall be located on the control panel. Lamps or LEDs to indicate that the MG output contactors are on shall be provided on the control panel. Separate indicators shall be provided for each output contactor.

3.5.3.2 Aircraft interlock bypass indication. A lamp or LED to indicate that the aircraft interlock circuit (E/F circuit) is bypassed shall be provided on the control panel.

3.5.3.3 Voltmeter. A voltmeter shall be provided to monitor AC volts. The AC voltmeter shall also have a selector switch to select phase voltages. The meter shall indicate the entire operating range of the MG with a minimum accuracy of +/- 3%.

3.5.3.4 Ammeter. An ammeter shall be provided to monitor AC amps. The AC ammeter shall also have a selector switch to select phase currents. The meter shall indicate the entire operating range of the MG with a minimum accuracy of +/- 3%.

3.5.3.5 Frequency meter. A meter shall be provided to indicate the output frequency of the MG. The meter shall have a minimum range of 390-410 Hz.

3.5.3.6 Multiple output AC power displays. The MG shall be equipped with a means to toggle between any of the 400 Hz output devices to allow operator and maintainer viewing of AC power parameters, i.e. volts, amps, and frequency. This device shall provide a display selection between the output devices and work in conjunction with the volt, amp, and frequency meters described herein. If a multi-function display is chosen, the MG shall continuously display the voltage, amperes, and frequency for any one output contactor/cable. The “Master” cable shall be the default display, with other cables/contactors selectable.

3.5.3.7 Voltage sensing. The MG shall be equipped with a device to manually select local or remote sensing for AC power ALDC. Additionally the MG shall be equipped with a device to select manual or automatic line drop compensation. These devices shall be located away from the normal operator interface via locked menu, cabinet door, or other similar means.

3.5.3.8. Auxiliary receptacle control. The MG shall be equipped with a circuit breaker to control the single phase 30 amp rated convenience receptacle in 3.9.4 herein. This control does not have to be located on the control panel.

3.5.4 Fault system instruments and controls. The MG fault system shall work in conjunction with the BITE system in 3.5.1.3 herein.

3.5.4.1 System alarm. A lamp(s) or LED(s) to indicate that fault conditions exist shall be provided on the MG control panel. This indication shall be latched in the "ON" position during alarm/fault conditions and shall remain "ON" until the alarm reset push-button is pressed. The MG shall be capable of detecting and displaying as a minimum the conditions listed below:

Input over/under voltage

Output over/under voltage

Input over/under frequency

Output over/under frequency

Output overload

E/F pin (interlock) failure

Over-temperature

Control logic failure

3.5.4.2. Audible alarm. An audible alarm to sound the MG alarm condition shall be provided on the control panel.

3.5.4.3. Alarm silence. A device to silence the MG audible alarm shall be provided on the control panel. This device shall not clear the fault or reset failure indicators. A lamp or LED shall be provided on the control panel to indicate the alarm silence device is in the enabled position.

3.5.4.4. Alarm reset. The MG shall be provided with a device to reset or clear all alarm or test failure indications. This device shall not prevent a fault from being displayed again if it is still valid. This device shall be located away from the normal operator interface via locked menu, cabinet door, or other similar means.

3.5.4.5 Push-to-test device. A push-to-test button or switch shall be provided to test the indicating lamps, LEDs, and display panel for the MG.

3.6. Safety characteristics. The MG shall be designed so that all electrical components are enclosed and access is not required during normal operation. Further, the MG shall be designed to safely permit access to internal components that may be required during troubleshooting for failures or other special needs. All exposed parts that are a hazard to personnel shall be insulated, enclosed, or guarded without impairing the function of the parts. The MG design shall not contain any system safety mishap risk categories greater than medium as defined in Table A-IV of MIL-STD-882D. The MG shall have as a minimum the safety characteristics/protective circuits listed below.

3.6.1. Input under/over voltage protective circuit. The input undervoltage or overvoltage protective circuit shall trip and alarm the MG when the voltage is out of the specified range for more than 5 seconds. The MG shall trip and alarm when one or more phases of the input power is out of the specified range or drops out altogether. The loss of input power phase shall trip the MG.

3.6.2. Output under/over voltage protective circuit. The output undervoltage or overvoltage protective circuit shall trip and alarm the MG when the voltage is out of the specified range. Output voltage limits of the MG shall be: undervolts 108 VAC for 3 seconds; overvolts 132 VAC for 1 second. These limits shall be adjustable (via a locked menu or inside enclosure-away from normal operator interface), but preset at the factory to above limits.

3.6.3. Interlocking control. The MG set shall have adequate circuitry so that during motor start-up it shall be impossible to close the output circuit breakers/contactors until such time that normal 400 Hz voltage, within the limits set forth herein, is present on the 400 Hz output buss system.

3.6.4. Door interlock. When any access door is open, the door interlock protective circuit shall open the 50/60 Hz input device and the 400 Hz output device and shall not allow the MG to close either device. A bypass switch for maintenance purposes shall be provided to defeat each door interlock circuit.

3.6.5. Output overload. The output protective circuit shall trip the output contactors when the output of the MG is above the limits set forth 3.4.13 herein.

3.6.6. Automatic capacitor discharge. The MG shall be designed so that when the unit is turned off under normal procedures or the “EMERGENCY STOP” switch is activated all capacitive devices are discharged to prevent hazardous voltages from remaining in the unit. The discharge rate shall be selected to prevent damage to the components. No voltage greater than 15 Volts shall exist on the load side of the input control device one (1) minute after the unit is turned off.

3.6.7. Input/output frequency protective circuit. The MG shall trip and alarm if the input or output frequency is out of the specified range.

3.6.8. Over-temperature. The MG shall be equipped with devices to monitor, trip, and alarm for thermal overload conditions or overheating components.

3.6.9. Motor protection. The MG shall be equipped with three phase motor overload protection. The MG shall also be equipped with protective devices to disconnect the input power supply from the motor to prevent damage in the event that the motor fails to start or accelerate. Additionally the MG shall be equipped with reverse phase sequence protection to prevent the application of 3 phase, 60 Hz voltage if the rotation of the motor generator is in the wrong direction or any phase is not present.

3.6.10. Ground fault protection. The MG shall contain a sensing circuit to provide protection to the input power circuit from ground faults. When activated by a fault condition, this circuit shall trip the unit from the input power.

3.7 Environmental. The MG shall meet the operating and non-operating characteristics listed below. The MG shall be designed to permit safe operation within the climatic specifications listed below. The MG shall permit safe operation in inclement weather conditions to include but not be limited to: wet/damp, dry/dusty, hot/cold, or any combination thereof.

3.7.1 Operating temperature. The MG shall be capable of operation from -40 degrees Fahrenheit to 125 degrees Fahrenheit.

3.7.2 Non-operating temperature. The MG shall be capable of storage from -60 degrees Fahrenheit to 165 degrees Fahrenheit.

3.7.3 Altitude. The MG shall be capable of operation from sea level to a minimum of 7000 feet. In altitude conditions from sea level to 5000 feet the MG shall provide rated electrical capacity while operating in 125 degree Fahrenheit conditions. In altitude conditions from 5000 to 7000 feet the MG shall provide rated electrical capacity while operating in 105 degree Fahrenheit conditions. Derating of the MG is allowed at temperatures and elevations exceeding the above listed conditions. Example: output power derating is allowed while operating in a 125 degree Fahrenheit 5500 feet above sea level environment, but not allowed in a 125 degree F 3500 ft above sea level environment.

3.7.4 Humidity. The MG shall be capable of operation and storage (non-operation) from 5 to 95% (±5%) relative humidity, including conditions where condensation takes place in the form of water and/or frost.

3.7.5 Solar radiation. The MG shall not be adversely affected by full time exposure to solar radiation, such as those conditions encountered in desert-like environments.

3.7.6 Fungus. All materials used in the MG shall be fungus resistant or shall be suitably treated to resist fungus. Materials treated for fungus resistance shall retain their original electronic and physical properties, shall not present toxic hazards, and treatment shall last for the entire service life of the part. The MG shall be suitable for use in conditions encountered in a tropical environment.

3.7.7 Salt laden moisture (salt-sea atmosphere). The MG shall be capable of sustained use and storage in high temperature, high humidity, salt laden, sea coast environments without damage or deterioration of performance.

3.7.8 Sand/dust. The MG shall be capable of sustained use and storage with exposure to 0.062 grams/cubic foot wind-blown sand (particle size 150-1000 microns) or dust (particle size less than 150 microns) at wind speeds up to 40 miles-per-hour (mph) without damage or deterioration of performance.

3.7.9 Precipitation. The MG shall have the following operational and non-operational characteristics for precipitation:

a. Rain: The MG shall be able to withstand exposure to rainfall at the rate of 5 in/hr at an angle from vertical to 45 degrees with 40 mph winds.

b. Snow/ice: The MG shall withstand at a minimum: snow accretion up to 2 in/hr for 12 hours; ice accretion of 1.5 inches.

3.8 Physical. The MG shall have the physical characteristics listed below. The MG shall be designed in accordance with MIL-STD-1472FC1 for ease of operation, inspection, and maintenance, including the use of arctic clothing and mittens and MOPP Level 4 Chemical Warfare Gear including chemical, biological, and radiological clothing and rubber gloves.

3.8.1 Materials. MG components and materials shall be selected for the purpose defined herein with consideration given to the minimum acceptable service life and the environmental conditions stated herein. The use of recovered or recycled materials is highly encouraged. The use of composites or light weight material is also highly encouraged. Magnesium alloys, wood products, polyvinylchloride (PVC) products, polyester, materials containing asbestos, or RTV which yields acetic acid shall not be used. Materials defined as Class 1 or Class 2 Ozone Depleting Compounds/Substances (ODC/ODS) shall not be used. Materials used in construction of the MG shall not be nutrients for fungi unless these materials have been treated with an anti-fungal coating which will last for the service duration life of the component. Unless protected against galvanic corrosion dissimilar metals and materials, as defined by MIL-STD-889B Change 3, shall not be in direct contact with one another. Metal plating or metal spraying of dissimilar base metals to provide electromotively compatible abutting surfaces is acceptable.