1、SAE ARPxSO9C 80 W 8357390 0028996 3 = !Ir WAC AEROSPACE RECOMMENDED p RACTI CE Society 400 COMMONWEALTH of Automotive DRIVE. WARRENDALE. Engineers, PA Inc. 15096 AN -N NATIONAL STANDARD I ARP 504C Issued 11- 15- 76 Revised 4- 15- 80 - I IGNITION SYSTEM TESTING - METERING AND POWER SUPPLIES 1. PURPOS
2、E This Aerospace Recommended Practice (ARP) provides a design standard for power supplies applicable to ignition system development testing. 2. SCOPE This procedure establishes the ignition system power supply design parameters for aero- nautical engine ignition system testing. 3. FOR D.C. SYSTEM ME
3、ASUREMENTS 3.1 3.2 3.3 3.4 3.5 3.6 0 Use meters with accuracy of 2% of full scale or kl volt , whichever is less. Use lowest range meters for minimum error readings of mid-scale, or greater. Use power supplies having not more than 1 volt drop at the terminals when a 10 ampere load is applied. Use a
4、capacitance across the power supply terminals large enough (2000 mfd plus) to ensure meeting ripple requirements of 3.3 and to provide a low impedance return path for the A.C. component that may be developed by the ignition exciters. The power supply shall be capable of being varied over the nominal
5、 supply voltage range that wiU be available to the system so as to allow checking of operation at the design limits of the system. Use power supplies having A.C. RMS ripple content no greater than 3% of average D .C. level, measured with 10 ampere load. Power supply circuit accessories such as filte
6、rs, relays and long power leads should be considered part of the power supply and meet the above requirements. Locate meters for measuring input characteristics at the input terminal of the system. Use moving coil type D .C. ammeters with i 2% accuracy for measuring average value of input current. D
7、ue to the varying characteristics of the input current over the charging cycle in capacitor discharge type system, the input current should be specific and read as the average of the minimum and maximum meter indications. If an automatic electronic averaging meter is available, it may be used. Digit
8、al meters are not recommended due to the varying CharactePistics. If it is required to measure current peaks, a suitable peak reading instru- ment may be connected external to the supply. 4. FOR A.C. SYSTEM MEASUREMENTS 4.1 Use frequency meters with accuracy of Il% of full sclae. Use lowest range me
9、ters for min- imum error readings at mid-scale , or greater. CopyriQht 1980 by Societ of Automotive Engineen, Inc. All rights reserveJ. Printed in U. S.A. 4RP 504C -2- 1 4.2 Use electronic true RMS , dynanmmeter or iron vane type meters with 5 28 of full scale accuracy for meneuring input current or
10、 voltage RMS value. Meters should be calibrated, or accuracy rnte, up to the highest frequency to be measured. Due to the varying characteristics of the in- put current over the ehinrging cycle in capacitor discharge type systems, the input current shoulc be specified and read na the average of the
11、minimum and maximum meter indications. Digital nmmetore aro not recommended due to this varying characteristic. If it is required to measure current peaks, n suitable peak reading instrument may be connected external to the power supply 4.3 Use power eupplieei having regulation capable of providing,
12、 at the exciter terminal, input fre- quency and voltage in aecordance with applicable ignition system specifications required when Ignition load is applied. 5. POR SELF-CONTAINED TYPE SYSTEM MEASUREMENTS 5.1 An engine driven permanent magnet generator (PMG or alternator) provides self-contained A.C.
13、 power in this type system to make it self-sufficient (MIL-E-5007D, 3.74 and 3.7.5.2). The generator output frequency ancl voltage are proportional to engine RPM and are usually specified for ignition system measurements at 100% speed (RPM) and the minimum RPM at which ignition is required. 5.2 A po
14、wer 6ource suitable for self-contained system measurements is shown in Fig. 1, where the generator should be simulated as follows : DESIRED LOAD - Figure 1 a) The A.C. supply must be adjusted to the specified generator output voltage(s1 at the speci- fied frequoncy(s1 and should have a drop in volta
15、ge (at V) of not more than 2$, when S1 is closed and L and R conform to 5.2(b) b) Internnl impedance of the generator should be simulated by the resistor R and inductor L suck that the meter readings of Pig 1 are: V = the required generator open circuit voltage(s) at the specified frequency(s) . I =
16、 the required generator ahort circuit current(s1 at the specified frequency(s) and voltage(s), when 81 is closed with S2 open. 6) Power factor correction using a suitable capacitor across the A.C. power supply terminals ma3 aid in attaining the requirements of 5.2(a) and (b). PROBLEM HARD COPY SAE A
17、RPUSOLIC 80 M 8357390 0028Li98 7 7 -3- ARP 504C 5.2 (continued) d) To determine the values of R and L required to satisfy 5.2(b) , if they are not already available as part of the required test equipment, consult the generator and ignition exciter specifications. if a range is specified. The inducta
18、nce of this resistor should be less than .i% of inductance L. The internal generator inductance may be calculated using specified open circuit voltage E (volts) and short circuit current I (amperes) for a high RPM such as 100% speed, where only L dominates. The frequency (in Hertz) is obtained from
19、generator RPM by f = (RPM) x (No. of poles in PMG/12O). The inductor value is then L = (E/I)/2n f, in henries, Test the resistor and inductor used by measuring V and I of 5.2(b) at the required frequency. Use the maximum value of internal generator D .C. resistance for resistor R, 5.3 Use electronic
20、 true RMS, iron vane, or dynamometer type meters with ?: 2% accuracy or better, for true RMS current and voltage measurements (V and I of Fig. 1). Meters must be calibrated, or accuracy rated , up to the highest frequency to be measured. Due to the varying characteristics of the input current over t
21、he charging cycle in capacitor discharge type system, the current should be specified and read as the average of the minimum and maximum meter indications. Digital meters are not recommended due to this varying characteristic. If it is required to measure current peaks, a suitable peak reading instr
22、ument may be connected external to the power supply. 5.4 Measurements on the ignition exciter should be performed using the simulated generator of Fig, 1 , with 52 closed and S1 open, after 5.2 and 5.3 have been satisfied. 6. NOTES 6.1 Marginial Indicia: The phi (0) symbol indicates technical changes from the previous issue of this document, PREPARED BY I l SAE COMMITTEE E- 30 , IGNITION RESEARCH .* 0
