1、INCH-POUNDMIL-PRF-24021K08 July 1998 _SUPERSEDINGMIL-E-24021J30 June 1986PERFORMANCE SPECIFICATIONELECTRIC POWER MONITORS, EXTERNAL, AIRCRAFTThis specification is approved for use by all Departments and Agencies of the Department ofDefense.1. SCOPE1.1 Scope . This specification covers electric power
2、 monitors which are installed in aircraft tomonitor external electric power to prevent power outside the limits of this specification from beingapplied to equipment in the aircraft.2. APPLICABLE DOCUMENTS2.1 General . The documents listed in this section are specified in sections 3 and 4 of thisspec
3、ification. This section does not include documents cited in other sections of thisspecification or recommended for additional information or as examples. While every effort hasbeen made to ensure the completeness of this list, document users are cautioned that they mustmeet all specified requirement
4、s documents cited in sections 3 and 4 of this specification, whetheror not they are listed.2.2 Government documents .AMSC N/A FSC 6110DISTRIBUTION STATEMENT A . Approved for public release; distribution is unlimited.Beneficial comments (recommendations, additions, deletions) and any pertinent data w
5、hich maybe of use in improving this document should be addressed to : Commander, Naval Air WarfareCenter Aircraft Division, Code 414100B120-3, Highway 547, Lakehurst, NJ 08733-5100, byusing the Standardization Document Improvement Proposal (DD Form 1426) appearing at theend of this document or by le
6、tter.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-24021K22.2.1 Specifications and standards. The following specifications and standards form a part ofthis document to the extent specified herein. Unless otherwise specified, the issues of t
7、hesedocuments are those listed in the issue of the Department of Defense Index of Specifications andStandards (DoDISS) and supplement thereto, cited in the solicitation (see 6.2).SPECIFICATIONSDEPARTMENT OF DEFENSEMIL-E-81910 - Elec trical Power Generating and Control Equipment, Aircraft,General Spe
8、cification forSTANDARDSFEDERALFED-STD-595 - Colors Used in Government ProcurementDEPARTMENT OF DEFENSEMIL-STD-130 - Identification Marking of U. S. Military Property(Unless otherwise indicated, copies of the above specifications and standards are availablefrom the Standardization Document Order Desk
9、, 700 Robbins Avenue, Building 4D,Philadelphia, PA 19111-5094.)2.3 Order of precedence . In the event of a conflict between the text of this document and thereferences cited herein, the text of this document takes precedence. Nothing in this document,however, supersedes applicable laws and regulatio
10、ns unless a specific exemption has been obtained.3. REQUIREMENTS3.1 Qualification . External, aircraft, electric power monitors furnished under this specificationshall be products that are authorized by the qualifying activity for listing on the applicable qualifiedproducts list before contract awar
11、d (see 4.2 and 6.3).3.2 Materials . Materials used in the manufacture of electric power monitors shall meet therequirements specified herein. Materials conforming to contractors specifications may be usedprovided the specifications contain provisions for tests and the required life , performance, re
12、liabilityand warranty period are achieved. The use of the contractors specifications does not constitutewaiver of Government inspection.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-24021K33.2.1 Metals .3.2.1.1 Corrosion resistance . Materi
13、als shall be corrosion resistant or processed to withstandthe environmental test requirements of MIL-E-81910.3.2.2 Toxicity and fire resistance . Non-metallic materials used shall be flame resistant, shallnot support combustion, and shall be nontoxic when exposed to flame as well as when used undera
14、ll operating and environmental conditions herein (see 3.5).3.3 Performance and interface characteristics .3.3.1 Mean flight hours between failure (MFHBF) . While operating under specifiedconditions, the minimum MFHBF for the power monitor shall be 10,000 hours for its first 5.5 yearsof service life,
15、 including storage.3.3.2 Maintainability . The electric power monitor shall meet the requirements of thisspecification for its complete 5 .5 year service period, without the need for any routine servicing ormaintenance actions. The monitor shall not include any provision for disassembly or inspectio
16、n.3.3.3 Repairability . The electric power monitor shall be non-repairable. The monitor shall bedesigned and constructed to hinder disassembly or access to internal components.3.3.4 Adjustments . No provisions for external adjustments shall be provided and noadjustment or alignments shall be require
17、d during installation of any power monitor. Alladjustments shall be made at the time of manufacture or when a monitor is being restored to a likenew condition. If devices for making adjustments are installed within a monitor, means for lockingand sealing shall be provided.3.3.5 Electron tubes . Vacu
18、um or gas filled electron tubes shall not be used.3.3.6 Capacitors . Wet slug tantalum capacitors shall not be used.3.3.7 Threaded parts . All internal or external parts which are threaded shall be positivelylocked. Accidental loosening of threaded parts shall be prevented by self-locking nuts, safe
19、tywiring, or other methods. Stacking shall not be used.3.3.8 Moving parts . The monitor shall be a completely static solid-state device having nomoving parts except that one electro-mechanical relay may be used for controlling the AC or DCpower to operate the external power contactor.3.3.9 Color . T
20、he monitor shall be finished in accordance with FED-STD-595, color number17875, or equivalent.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-24021K43.3.10 Cooling . The monitor shall be self-cooled by convection and radiation. Conductioncool
21、ing shall not be allowed. Safe operation equilibrium temperature shall be maintained for allparts over the specified range of operating conditions, and rated temperatures of parts shall not beexceeded.3.3.11 Ventilation openings . All ventilation and other openings shall be designed to preventpassag
22、e of foreign objects and shall be of such size as to prevent passage of spherical objects of0.188 inch diameter or larger.3.3.12 Operating attitude . The monitor shall operate in any attitude.3.3.13 Dimensions . The dimensions of the monitors shall conform to figure 1. Where onlyminimum or maximum d
23、imensions are shown on the figure, the monitor need not have the shapeshown on the figure, but the monitor, including all protrusions, shall be contained within the outlineshown on figure 1.3.3.14 Part number, weight and height . The part number shall be in accordance with 6.7 andtable I. The weight
24、 and height of each monitor shall be not greater than the value listed in table I.3.3.15 Electric receptacle . Each monitor shall include an electric receptacle which shall becompatible with the mating electric plug called out in table I and shall be installed on the monitor inaccordance with figure
25、 1, with the largest polarizing key or keyway of the receptacle at the topcenter of the receptacle shell.3.3.16 Compatibility . The monitor shall not degrade the power systems ability to provide thepower characteristics specified in 3.4.4.1 or 3.4.4.2, as applicable. DC monitors shall include ametho
26、d in the output circuit to clamp negative transients to ground.3.3.17 Environmental protection . A means shall be provided for protecting printed circuitboards from environmental effects (see 6.5).3.3.18 Sneak circuits . Sneak circuits shall not be allowed.3.3.19 Installation . The monitors shall be
27、 connected in accordance with figures 2, 3, or 4, asapplicable.3.3.19.1 Reset switch . A reset switch shall be provided as shown on figures 2, 3, or 4, asapplicable. The switch shall be a push-button type, spring-loaded to the normal (open) position,with momentary movement to the reset (closed) posi
28、tion. The switch shall not include any meansfor locking it in the reset position.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-24021K53.3.20 Overload protection . A circuit protective device shall be provided for each monitor inorder to pro
29、tect the circuit which supplies or carries (as applicable) the current to the contactor. Monitors shall be protected for 10 amperes as follows : M24021-3 monitors at pin 5, M24021-5monitors at pin F, and M24021-6 monitors at pin A. The devices shall be a fast-acting typedesigned for protection of se
30、mi-conductor devices.3.4 Performance . The power monitor shall meet the following performance requirements forAC and DC operation.3.4.1 Input power requirements .3.4.1.1 Input of electric power to AC monitors . Each AC monitor shall withstand withoutdamage, and shall not reset automatically upon app
31、lication of three-phase, four-wire, wye-connected, grounded-neutral, alternating potential having the following characteristics whenapplied according to figure 5 or 6, as applicable.a. Three-phase, steady-state voltage, of a frequency between 300 and 500 Hz between line andneutral, and applied betwe
32、en monitor pin 4 and pins 1, 2, and 3, or between pins G and A, C and E,as applicable. The monitor shall not be damaged when these voltages in the range of 0 to 140 voltsRMS are applied continuously and in the range of 140 to 200 volts RMS are applied for a period ofone-half hour.b. Total harmonic c
33、ontent shall be not greater than 5 percent of the fundamental. Individualharmonic content shall be not greater than 3 percent of the fundamental.c. Any phase sequence.d. Three phase steady-state voltages of 11 5 RMS volts and 60 Hz frequency applied betweenmonitor pin 4 and 1, 2, 3 or between pins G
34、 and A, C and E, as applicable for 30 seconds.3.4.2 Input power to DC monitors .3.4.2.1 Input of electric power to power lead (pin G) and sense lead (pin B) . Each DC monitorshall withstand without damage, and shall not reset automatically regardless of inhibit voltage valueupon application of, grou
35、nded-negative direct potential having the following characteristics whenapplied to pins G and H, and B and H, in accordance with figure 7.a. Any average value between -80 and +80 volts applied continuously.b. Ripple from a power source whose individual frequency characteristics are in the 10 Hz to40
36、 kHz range and whose ripple voltage can vary from 0 to 10 volts peak-to-mean.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-24021K6c. Spikes from 0 to “ 600 volts from the average voltage level, with a 50-ohm sourceimpedance, a waveform as s
37、hown on figure 8, and a repetition range of 0 to 50 pulses per second.Application of the spike shall not cause the monitor to disconnect power from the contactor.d. The current drawn through the sense lead (pin B) shall be less than 50 milliamperes.3.4.2.2 Inhibit voltage at pins C and E . The M2402
38、1-6 monitor shall be designed to accept atpins C and E (see figure 7) an aircraft-generated direct DC potential of -15 to +80 volts (inhibitvoltage) originating at the starter system. When a 2 to 80 volt inhibit voltage is applied at pin C orE and the monitor is in the reset state (the external cont
39、actor on figure 7 is energized), the monitorshall remain reset and, in addition, shall be inhibited within 0.1 second from the time the2 to 80 volt inhibit voltage is applied. In the inhibit mode of operation (2 to 80 volt inhibit voltageis applied at pins C or E), the monitor shall accept any input
40、 voltage present at pin G (input at pin Gwill be within the limits specified by curves on figure 9, 10 volts DC to 80 volts DC) and apply it tothe aircraft contactor at pin A. The maximum voltage drop between pins G and A shall be notgreater than 2.5 volts when the monitor input voltage is in the ra
41、nge of 10 to 29.1 volts DC. The 2to 80 volt inhibit voltage shall not be applied to both pins C and E simultaneously when the monitoris operating in the inhibit mode. When a 2 to 80 volt inhibit voltage is applied at pin C or E and themonitor is in the trip state (monitor output at pin A is 0 volts)
42、, the monitor shall remain in the tripstate and shall reset only manually as specified in 3.4.4.2.1.a. When an inhibit voltage of -15 to +1.5 volts is applied to both pins C and E, the monitorshall function as specified in 3.4.4.2.1. If the inhibit voltage decreases from a higher value to avoltage o
43、f less than 1.5 volts and the monitor is in the reset state (the external contact on figure 7 isenergized), the monitor shall function as specified in 3.4.4.2.1 within 0.1 second from the time theinhibit voltage decreases to a voltage of less than 1.5 volts.b. The non-inhibited (normal) requirements
44、 stated herein shall be met als o when pin C or E orboth are not connected to any external circuit.c. When the inhibit voltage at pins C or E is in the range of 1.5 to 2 volts, the monitor mayoperate either in the inhibited or in the non-inhibited (normal) mode.d. The internal circuit of the monitor
45、 shall incorporate a 10 kilo-ohm resistor in series with pinC and a 10 kilo-ohm resistor in series with pin E.3.4.3 Output requirements .3.4.3.1 AC monitor including source of DC for contactor . When the external power applied tothe M24021-3 monitor meets the reset conditions specified in 3.4.4.1, t
46、he monitor shall, uponmomentary closing of the reset switch, activate a switching circuit which will apply a directProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-24021K7potential of 26 “ 4 volts between pins 4 and 5 of the monitor receptacle
47、. The internal circuitconnected to pin 5 shall have a current capacity not less than 1.5 amperes continuously and15 amperes for 200 milliseconds (msec) at 115 volts AC input. The output shall energize theaircraft AC external power contactor, thus connecting the AC external power to the aircraft load
48、.The cyclic peak-to-mean of ripple voltage to the mean level of the monitor DC output voltage shallbe less than 1.5 volts under all input and output conditions.3.4.3.2 AC monitors excluding power supply . When the external power applied to theM24021-5 monitor meets the reset conditions specified in
49、3.4.4.1, the monitor shall, uponmomentary closing of the reset switch, activate a switching circuit or relay which will connecttogether pins F and H of the monitor receptacle. The switching circuit between these pins shallhave a DC or AC capacity of at least 5 amperes continuously and 15 amperes for 200 msec. Theswitching circuit shall control the application of 26 “4 volts DC or 112.8 to 118.2 volts AC(externally applied to pin H) to the external power cont
