CCP AT 121 - AT 121 Chapter 7a – Charging Systems (5 pages)

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AT 121 Chapter 7a – Charging Systems



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AT 121 Chapter 7a Charging Systems Name Group Date Symptom Chart Condition Charging system malfunction high or low system voltage Dead battery or battery will not stay charged Charging system warning indicator malfunctioning light on with engine running light off with key on engine off light on with key off Generator is noisy Radio interference Possible Sources A circuit fuse link B circuit fuse links Generator PCM Regulator Loose Damaged Drive Belt Defective Generator Defective Battery B Circuit High key off load Parasitic Drain Loose corroded terminal s Charging system warning indicator bulb Instrument cluster Generator PCM Regulator Loose bolts brackets Drive belt Generator Bearings Generator Wiring routing poor grounds In vehicle entertainment system Tools you will need 2001 Honda Accord or 1997 Acura 2 2 CL Alternator Specifications 80 Amps at 2000 RPM 70 Deg F Factory Shop Manual Straight Edge DVOM ARBST Tester Amp Probe SECTION 1 Inspect Accessory Drive Belt Condition and Tension Incorrect belt tension will cause undercharging A loose belt will slip and squeal An over tightened belt will cause will cause bearing damage An oily belt will slip but be quiet Misaligned drive belts will cause fraying and constantly be thrown off Tension Spec Is there oil on the belt Yes No Drive the belt show signs of chunking Yes No Are the pulleys in alignment Yes No Is the accessory drive belt OK Yes No SECTION 2 Check Generator Connections Poor generator connections will cause high resistance in the B circuit This will cause a voltage drop Are the generator connections B Ground and Regulator Connections clean and tight Yes No 1 SECTION 3 Charging System Voltage With the engine running monitor the voltage at the battery Is the battery voltage between 13 and 15 volts Yes No What is the battery voltage When finished have the instructor sign off on your work SECTION 4 Voltage Drop Tests Output Circuit Insulated Power Side Place one end of the meter at the B terminal of the alternator Place the other end of the meter at the terminal of the battery Run the vehicle with no loads at 2000 rpm The voltage drop should be less than 0 5 volts The voltage drop is If the voltage drop were greater than 0 5 volts this would indicate high resistance in the B circuit of the alternator A corroded wire or terminal end could be the cause Output Circuit Ground Side Place one end of the meter at the case of the alternator Place the other end of the meter at the terminal of the battery Run the vehicle with no loads at 2000 rpm The voltage drop should be less than 0 2 volts The voltage drop is If the voltage drop were greater than 0 2 volts this would indicate high resistance in the ground circuit of the alternator A corroded wire or terminal end could be the cause as well as a poor engine ground or loose alternator mount SECTION 5 Checking for Diode Ripple AC voltage no not THAT Ripple Checking Ripple Voltage Ripple voltage or AC voltage can be measured by switching the DVOM to AC and connecting the black lead to a good ground and the red lead to the B on the back of the alternator A good alternator should measure less than 5 VAC with the engine running A higher reading indicates damaged alternator diodes Voltage A C Pass Fail 2 Q At what RPM should the voltage drop tests be done at A voltage drop of more than indicates high resistance in the B circuit A voltage drop of more than indicates high resistance in the ground circuit When checking for AC diode ripple if the AC voltage is more than volts the diodes in the alternator may have failed What will be the end result of an over tightened belt What would cause the belt to slip even if it were tight When would one hear a loose alternator belt Name 5 things that would cause a generator to undercharge When finished have the instructor sign off on your work SECTION 6 Alternator Load Testing Following the procedure demonstrated to you by the instructor test the alternator using the ARBST tester ARBST Tester Results Volts Amps Diodes Leaving the ARBST tester hooked up With the engine running turn the A C on the blower motor on high speed and the headlamps on high beam Increase the engine speed to approximately 2 000 rpm The voltage should increase a minimum of 0 5 volt above the base voltage The total amps should be close to the maximum of the alternator total output Fact is this test can be done with any inductive amp meter Volts Amps If voltage were low the next step would be to full field the alternator Full Fielding the Alternator WARNING DO NOT FULL FIELD ALTERNATOR FOR MORE THAN 10 SECONDS AT A TIME Ground the F terminal Results Volts This test bypasses the regulator and sends full field voltage and current to the rotor assembly Voltage should be about 1718 volts If not a damaged rotor or stator is possible If voltage DOES go up but falls back to a voltage lower than 13 volts the regulator is bad 3 If the voltage does not go up on a full field test what is at fault If the voltage does go up on a full field test but then falls below 13 volts what is at fault When finished have the instructor sign off on your work SECTION 7 Generator Removal and Installation Tools you will need Tool Board 1996 Ford Thunderbird or 1991 Lincoln Towncar Snap On Alternator Tester Removal Disconnect battery ground cable Remove engine appearance cover Remove generator bracket bolts Disconnect voltage regulator wiring and output cable from generator Remove serpentine belt from generator pulley Remove remaining bolts from generator and remove generator Item 1 2 3 4 A B Description Generator Mounting Bracket Bolt 4 Req d Generator Mounting Bracket Generator Mounting Bolt 2 Req d Generator Tighten to 10Nm 89 Lb In Tighten to 25Nm 18 Lb Ft Installation Install generator Tighten front generator bolts to 25Nm 18 lb ft Install serpentine belt Connect voltage regulator wiring and output cable Tighten cable nut to 8Nm 71 lb in Install generator bracket bolts and tighten them to 10Nm 89 lb in Install engine appearance cover and securely tighten the nut Connect battery ground cable Be sure to properly torque all fittings on the alternator A loose fitting will arc causing high heat and possible fire NEVER run a vehicle with a poorly grounded alternator Severe voltage spikes may occur and damage electronic components Test the alternator on this vehicle using the older style analog tester Set it to the 100 A scale remember to ZERO the meter Run all vehicle accessories and raise the RPM to 2000 for 20


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