2)  A multimeter connects to a clamp-on ac current probe which you put around one of the three wires which connect to the load side of 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.
 (3)  
Pressurize the three hydraulic systems at the same time during this test with a hydraulic service cart(s) or with an ACMP in each system.

 (4)  
The procedure for the gross internal leakage check 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 you 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.

 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% of the indication, specified for operation at 3000 psi.

 (b)  
Hydraulic Service Cart(s) - Commercially
 Available, which can supply 6 GPM to each
 system (18 GPM total) at 3000 psi

 NOTE: The service cart is not necessary
____ if you use the ACMP to pressurize the hydraulic system.
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 29-11-00
 ALL  ú ú 12 Page 641 ú May 20/98
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A

757
MAINTENANCE MANUAL

 C. References
 (1)  
AMM 06-41-00/201, Fuselage Access Doors and Panels
　
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