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MAINTENANCE MANUAL

 2)  A multimeter connects to a clamp-on ac current probe which you put around one wire at the ACMP ELCU in the P31 or P32 panel. The multimeter with the ac current probe measures the amperage which flows in the one wire to the pump motor. A graph shown in Fig. 605 changes the amperage to a hydraulic flow rate.
 (b)  Flowmeter Technique
 1)  The flowmeter technique uses a flowmeter to measure flow rates directly while the system is pressurized with an ACMP or a hydraulic service cart. You install the flowmeter in the pressure line between the pressure source and the pressure filter module.
 (4)  
Measure all leakage in the pressure side of the hydraulic system while the system is kept at approximately 3000 psi. Pressurize the three hydraulic systems at the same time during the test with a hydraulic service cart(s) or an ACMP in each system.

 (5)  
The procedure for the internal leakage check of the elevator and rudder PCAs follows. This procedure does a leakage check of one hydraulic system at a time. The sequence in which you do a test of the left, center and right hydraulic systems is not important. When start the leak check of a system, do not stop until you complete the procedure, to get correct results. In this procedure, all controls must be in the neutral position unless a different position is specified. After you make a test configuration for each test step, do not measure the leakage for at least 15 seconds. This will let the leakage flow become stable before you measure the flow.

 (6)  
The test procedure is in the paragraphs and figures which follow. Each figure is identified with the system and subsystem on which the test is done. The procedure is written in short steps. Make a mark on the figure next to each step when you do the step. There is space on each figure to write the flow, and the null and seal leakage. There is also space on each figure to calculate the leakage rates. A Corrective Action/Defective Component/Comment column tells how to correct a failure or isolate a defective component and tells more about the test step.

 B.  Equipment
 (1)  Use this equipment with the multimeter technique:
 (a)  
Digital Multimeter - John Fluke Model 27 YEL.

 (b)  
Clamp-on AC Current Probe - John Fluke Model 80i 600.

 NOTE: The ac current probe is used with the multimeter.
____
 (2)  Use this equipment with the flowmeter technique
 (optional to the multimeter technique):

 (a)  Flowmeter - Commercially Available, 0.2 to
 7.0 GPM range with a precision of |3 percent of the indication, specified for operation at 3000 psi
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