1、SAE ARP*715A 82 m 83573LiO O029003 3 m AEROSPACE I TheEngineerng ?some fiu hncing Mobility RECOMMENDED PRACTICE 400 COMMONWEALTH DRIVE. WARRENDALE. PA 15096 ARP 715A Superseding ARP 715 11-29-6 3 Issued Revised 2-25-82 PERFORMANCE ACCEPTANCE TESTING OF AIR TURBINE STARTERS 1. SCOPE: This Aerospace R
2、ecommended Practice describes two performance acceptance test methods to determine the performance acceptability of new production and overhauled air turbine starters. Before a new or overhauled starter is delivered to a customer, the starter is subjected to a performance acceptance test in accordan
3、ce with an acceptance test procedure. The performance acceptance test is intended to ensure that the customer receives a starter that meets or exceeds minimum starter performance requirements. 2. DISCUSSION: The first acceptance test method, called the acceleration time method, consists of measuring
4、 the elapsed time required by the starter to accelerate a flywheel to cutout speed with specified starter inlet conditions. required for a starter which meets the minimum performance requirements to accelerate the same flywheel to the same cutout speed with the same inlet conditions. The measured ac
5、celeration time is compared with the time The second method, called the rating point method, consists of measuring the starter output torque at various rating point speeds with specified starter inlet conditions while the starter is driving a flywheel or dynamometer. The measured torque is compared
6、with the torque that a starter which meets the minimum performance would produce at the same rating point speeds and inlet conditions. In addition to measuring acceleration time or rating point torque, both acceptance test methods require that the airflow be measured and compared with the maximum al
7、lowable airflow. The acceleration time method does not require a torque measurement device for acceptance testing. The performance of the unit is verified indirectly by measuring acceleration time. ?he rating point test method records the test unit torque and hence verifies the test unit output perf
8、ormance directly at several speeds. SAE Technical Board rules provide that: “All technical reports, including standards approved and practices recom- mended, are advisory only. Their use by anyone engaged in industry or trade or their use by governmental agencies is entirely voluntary. There is no a
9、greement to adhere to any SAE standard or recommended practice, and no com- mitment to conform to or be guided by any technical report. In formulating and approving technical reports, the Board and its Committees will not investigate or consider patents which may apply to the subject matter. Prospec
10、- tive users of the report are responsible for protecting themselves against liability for infringement of patents.“ Copyrighf 1982 Society of Automotive Engineers, Inc. - Ali rights reserved . /- y Printed in U.S.A. 2. (Continued): In addition to providing engine starts, some starters are required
11、to provide hydraulic and electrical power fol: ground checkout by motoring the aircraft accessories at a constant speed. %e rating point method may be used to verify the starter ground checkout performance, the test unit torque at the starter ground checkout speed with specified (Iraund checkout sta
12、rter inlet conditions and a suitable loading device. ?his is done by measuring 3. ACCEPTANCE TEST CUTERIA: The acceptance test performance criteria for the acceleration time and the rating point test methods are based on the starter minimum performance or torque/speed characteristic at some specifie
13、d starter inlet conditions of constant pressure and temperature as shown in Figure 1. fie specified inlet conditions are usually the starter design point or rated conditions. Instrumentation accuracy and tolerances on the specified inlet conditions should be considered in establishing the acceptance
14、 test limits. The maximum allowable airflow is calculated using the maximum air turbine starter nozzle area based on production tolerances and the specified inlet conditions a8 shown in Figure 1. test criterion because the minimum starter performance will sometimes occur with the maximum nozzle area
15、 in cases where the energy source is airflm- limited. In cases where the energy source is not airflow limited, th acceptance test limitation on airflow ensures that the maximum torque limits will not be exceeded. me limitation on airflow is an acceptance 3.1 Acceleration Time Acceptance Criteria: Th
16、e acceptance test criteria are the acceleration times calculated to accelerate a test stand flywheel to starter cutout speed utilizing the starter minimum torque/speed characteristics and the actual flywheel drag. provide elapsed flywheel acceleration times approximately the same as the start times
17、estimated for the engine. coordinated between the starter manulacturer and the customer. Ihe flywheel inertia should be selected to me selection of the flywheel is %e flywheel drag shown in Figure 2 is determined by testing. !%is is typically accomplished by allowing the unloaded flywheel to deceler
18、ate without braking from a speed higher than the maximum starter cutout speed, measuring the speed decay as a function of time, and calculating the drag torque by multiplying the rate of deceleration by the flywheel inertia. accurate determination of the flywheel drag must be obtained by testing of
19、the selected flywheel before acceleration times are calculated. a flywheel can vary after a period of time due to wear of the flywheel bearings. increased flywheel drag, the flywheel drag must be checked periodically. An ?he drag of To prevent unnecessary starter rejection as the result of Elapsed a
20、cceleration times to various speeds between minimum and maximum cutout: are calculated using the starter minimum performance torque curve and the flywheel drag as determined by testing. %he calculated acceleration times shown in Figure 3, together with the maximum allowable stall airflow, thus becom
21、e the starter acceptance test criteria. O t O O SAE ARPx715A 82 83573Ll0 0027005 7 3.2 Rating Point Acceptance Criteria: The rating point torque is determined from the minimum starter/torque characteristic for the specified rating point speeds as shown in Figure 4. selected to verify that the starte
22、r meets the minimum engine start torque/ speed characteristics. A single rating.point at the ground checkout speed is usually sufficient to verify that the starter meets the minimum ground Sufficient rating points must be que. The torque and speed values or rating points, together imum allowable air
23、flow, thus constitute the starter acceptance test criteria. 4. 4.1 4 e2 TESTING: Acceleration Time Method: The starter acceptance test is accomplished on a flywheel test stand. The specified starter inlet conditions at stall are established at the starter inlet while the flywheel brake is set to pre
24、vent flywheel rotation. Before the flywheel is released, the inlet temperature and pressure are allowed to stabilize. Any deviation in the starter inlet conditions beyond a reasonable tolerance band during acceleration to cutout speed will affect the starter torque/speed Characteristics and thus inv
25、alidate the test. airflow is measured, the brake is released, and the starter is allowed to accelerate to starter cutout speed. The start cycle is terminated either automatically by the starter cutout switch or manually, if the starter does not incorporate a switch. The recorded acceleration time to
26、 cutout speed is compared with the maximum allowable time which is the calculated acceleration time for a starter that meets the minimum starter performance. recorded time exceeds the maximum allowable time or if the recorded starter airflow at stall conditions exceeds the maximum allowable airflow.
27、 Rating Point Method: dynamometer or flywheel test stand. starter inlet conditions are established and stabilized as the starter is motored at each rating point speed. The steady-state torque and airflow at each rating point speed are recorded. If a flywheel test stand is utilized, the test is accom
28、plished in the same manner as previously described in paragraph 4.1. is continuously recorded as the starter accelerates to cutout speed. the recorded torque is transient in nature, it must be converted to steady-state conditions by multiplying the recorded torque by the ratio After the inlet condit
29、ions have stablized, the stall The starter is rejected if the The starter acceptance test is accomplished on a If a dynamometer is used, the specified The starter output torque Since ( IfI: Is), where If is flywheel inertia and Is is starter inertia. 4.2 (Continued): The starter steady-state torque
30、at each rating point is compared to the minimum allowable torque, (i.eet the torque that a starter meeting the minimum starte2 performance would produce at: the same rating paint inlet conditions* rating point is less than the minimum required torque or if the recorded Btarter airflow exceeds the ma
31、ximum allowable airflow bie starter is rejected if the starter torque measured at any PREPARED BY SAC COMMITTEE AE-6 STARTING SYSTEMS SAE ARP*L5A 82 83573LlO a829007 o MfmIMUM ALLOWABLE STALL AIRFLOW AT RATED INLET CONDITIONS = LB PEW MIN, EXAMPLES OF STARTER TORQUE DURING ACCEPTANCE TEST MlNlMUM ST
32、ARTER TORQUE AT -RATED LET CBNDlTlONS SPEED - RATED INLET CONDITIONS: PRESSURE = f BSlG TEMPERATURE = e OF FIGURE P AIR TURBINE STARTER MINIMUM PERFBPIMANCE CHARACTERISTICS I t w 85 w - RATED INLET C(aNDIT1BNS: PRESURE = -c. PSIQ TEMPERATURE = k “F t MlNtMUM STARTER TORQUE AT RATED INLET CBNDITIQNS EXAMPLES OF STARTER ACCEPTANCE TEST RESULTS MIMIMUM AND MAXIMUM STARTER CUTOCdT SPEEDS SPEED - FIGURE 4 AIR TURBINE STARTER RATING POINTS
