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____ multiplier switch setting.
2) Measure the resistance between pin 4 and pin 1 of the electrical connector installed on the fuel pump (Fig. 601, View B).
NOTE: If the pump resistance is very high, the
____ megohmmeter value will increase with time. For any resistance over 100 megohms it is not necessary to get the actual resistance value. Stop the measurement once the megohmmeter value is more than 100 megohms. Record the measurement on the data sheet as >100 megohms.
3) Record the resistance measured between pin 4 and pin 1 on
the 757 Fuel Pump Inspection Data Sheet (Fig. 602). 4) Set the function switch to the DISCHARGE position. 5) Do these steps again to measure the resistance between pin
4 and the remaining pins on the fuel pump connector, pins 2 and 3.
(e) Make an analysis of the test results:
1) If any resistance measured between pin 4 and pins 1, 2 and 3 is less than 1 megohm, do these steps: a) Replace the applicable fuel pump (AMM 28-22-03/401). b) Do the Continuity/Resistance Check on the replacement
fuel pump. c) Start with this procedure: Fuel Pump Continuity Check.
2) If each resistance measured between pin 4 and pins 1, 2 and 3 is equal to or more than 1 megohm, do this procedure: Final Insulation Resistance Check.
J. Final Insulation Resistance Check
S 766-050
WARNING: IF THE FUEL PUMP IS INSTALLED ON THE AIRPLANE, MAKE SURE THE
_______ QUADTECH MODEL 1864 (OR EQUIVALENT) MEGOHMMETER IS USED TO MEASURE THE INSULATION RESISTANCE. IF NOT, IT IS POSSIBLE THAT AN EXPLOSION OR FIRE CAN OCCUR.
(1)
Do these steps to connect the QuadTech Model 1864 Megohmmeter for the 500 VDC check:
(a)
Calibrate the megohmmeter if it is necessary.
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MAINTENANCE MANUAL
(b)
Plug the megohmmeter into a grounded receptacle.
(c)
Connect the +UNKNOWN probe to the pump connector pin 4 (ground).
(d)
Connect the --UNKNOWN probe to the pump connector pin 1.
(e)
Set the multiplier dial to the lowest range (1M).
(f)
Set the TEST VOLTAGE switches to 500V.
(g)
Set the measure switch to the MEASURE position.
S 766-066
(2)
Do these steps to measure the resistance at the pump:
(a)
Turn the multiplier switch until the meter reading is less than
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本文链接地址：757 AMM 飞机维护手册 燃油 CHAPTER 28 - FUEL 3(14)
