THE ALT AL ERNA RN T A OR

Transcription

1 THE ALTERNATOR Initial Voltage of the Battery (Engine Not Running) Charging Voltage for the Battery (Engine Running) Testing for Maximum Output of the Alternator Inspecting the Regulator Positive Side Voltage Drop Negative Side Voltage Drop Checking for Unwanted Draw

2 Testing the Initial Voltage of the Battery (Engine Not Running) Before any tests can be performed on the alternator, it is important to make sure that the battery is between 60 and 100 F, with a full charge. All connections must be clean and tight and the alternator belt must have the proper tension. Using a volt meter, connect the positive (+) red lead of a multimeter to the positive (+) battery terminal and connect the negative (-) lead of the meter to the negative (-) battery terminal. Compare the results to the chart below. If the reading is low (less than 12.4), the battery must be charged and re-tested. If the reading is high (greater than 12.6) then you must remove the surface charge. This may be accomplished by using one of the two methods below: Turning on the headlights for 5 minutes. Turning the starter over for seconds with the ignition disabled. Wait for an additional 5 minutes for the battery to stabilize after removing the surface charge.

3 Charging Voltage for the Battery (Engine Running) Using a volt meter, check to see if the battery has at least 75% state of charge (minimum 12.4V). Start the engine and increase the rpm to The voltage reading should increase, but should not exceed 15.5 volts. OVERCHARGE CONDITION: If the result is higher than 15.5 volts and the alternator has an internal regulator, make sure all electrical connections are clean and properly connected, before replacing the alternator. For external regulators connect the volt meter to the regulator housing and battery (-) terminal. If the reading is greater the 0.10 then the regulator is not properly grounded. Also, check the condition of the wires between the regulator and the alternator. NOTE: Some GM CS Series 4 Pin regulators can charge up to 16.0 volts. For this type of unit, the reading should not exceed 16.0 volts.

4 Charging Voltage for the Battery (Engine Running) (Cont d) LOW VOLTAGE READING: If the voltage is below the initial battery level, there may be a problem with the Regulator, Alternator or Wiring Harness. If the alternator has an internal regulator, make sure all electrical connections are clean and properly connected, before replacing the alternator. If the alternator has an external regulator see the 'Bypassing the Regulator section that follows. With the engine running at 2000 RPM and all accessories on high (air conditioner, wipers, headlights, heater fan etc.), if the voltage is at least 0.5 volts higher than the initial battery voltage, the alternator is good. Voltage is not 0.5 volts higher than the initial battery voltage: External type regulator, the regulator must be replaced. Internal type regulator, the alternator must be replaced.

5 Testing for Maximum Output Current Test the current of either battery cable, using an inductive amp probe, six inches from the alternator. Connect the load tester to the battery posts. With the engine running at 2000 rpm's, adjust the load tester to the maximum amperage reading possible, without allowing the battery voltage to fall below 12.5 volts. THE ALTERNATOR IS GOOD IF: Output is within 10% of the amperage rating for externally regulated alternators Output is within 10 amps (15 for CS series) of rating for internally regulated alternators If alternator has an internal regulator and the above conditions are not met, the alternator must be replaced. For external regulators, connect the volt meter to the regulator housing and battery (-) terminal. If the reading is greater than 0.10 then the regulator is not properly grounded. Also, check the condition of the wires between the regulator and the alternator. If the alternator still does not perform to current rating, refer to the next section ' Finding The Problem ' to determine where the problem is located. regulator ADJUSTABLE LOAD TESTER VOLTS AMPS Field Terminal Bat(+ ) Junction box (solenoid or relay)

6 Finding the Problem, A Circuit Type Bypassing the Regulator for Full Field Output (For single field terminal, negative ground alternators only) Voltage Regulator Test Connect the load tester with the amp inductive probe around either battery cable or the battery (+) alternator output cable. Remove the connector from the voltage regulator as shown below. Run a jumper wire from negative (-) battery terminal to the 'F' terminal on the plug. NOTE: Some alternators do not have external field wire access. See manufacturers ADJUSTABLE LOAD TESTER instructions to full field VOLTS these units. AMPS Field Terminal Bat(+) Junction box (solenoid or relay) Checking the Results Start engine, increase RPM slowly to 2000, at the same time apply load with the load tester. Warning!!! DO NOT LET VOLTAGE EXCEED 16 VOLTS! Allow enough of a load to determine maximum current, but do not let voltage drop below 12.5 volts. If current output now meets specifications, the regulator is bad. The alternator is good if current is within 10 % of current rating of alternator.

7 Finding the Problem, A Circuit Type (Cont d) Bypassing the Regulator for Full Field Output (For single field terminal, negative ground alternators only) If there is low or no output, run a jumper wire from negative (-) battery terminal to the field terminal on the alternator. Follow "Checking the Results" on previous page. If amperage now meets specifications, there is a problem with the wire between the regulator and the "F" terminal. ADJUSTABLE LOAD TESTER VOLTS AMPS Field Terminal Bat(+) Junction box (solenoid or relay) If there is still low output after the above test, then the alternator is faulty.

8 Voltage Regulator Test TESTING THE ALTERNATOR Finding the Problem, B Circuit Type Bypassing the Regulator for Full Field Output (For single field terminal, negative ground alternators only) Connect the load tester with the amp inductive probe around either battery cable or the battery (+) alternator output cable. Remove the connector from the voltage regulator as shown below. Run a jumper wire from positive (+) battery terminal to 'F' terminal on the plug. NOTE: Some alternators do not have external field wire access. See manufacturers instructions to full ADJUSTABLE LOAD TESTER VOLTS field these units. AMPS Field Terminal Bat(+) Junction box (solenoid or relay) Checking the Results Start engine, increase RPM slowly to 2000, at the same time apply load with the load tester. Warning!!! DO NOT LET VOLTAGE EXCEED 16 VOLTS! Allow enough of a load to determine maximum current, but do not let voltage drop below 12.5 volts. If amperage output now meets specifications, the regulator is bad. The alternator is good if current is within 10 % of amperage rating of alternator.

9 Finding the Problem, B Circuit Type (Cont d) Bypassing the Regulator for Full Field Output (For single field terminal, negative ground alternators only) If there is low or no output, run a jumper wire from positive (+) battery terminal to the field terminal on the alternator. Follow "Checking the Results" on previous page. If current now meets specifications, there is a problem with the wire between the regulator and the "F" terminal. ADJUSTABLE LOAD TESTER VOLTS AMPS Field Terminal Bat(+) If there is still low output after the above test, then the alternator is faulty.

10 Inspecting the Regulator Connect the load tester to the battery with the inductive amp probe around wire from the alternator positive (+) output terminal. Start the engine, and slowly bring the RPM to Adjust the load tester to achieve maximum current while not allowing the voltage to drop below 12.5 volts. This will force the regulator into a full field situation. Turn the load tester off (remove the load) while still monitoring the charge current. Wait until the charge current falls below 20 amps. Compare the battery voltage reading on the charts below.

11 Inspecting The Regulator (Cont...) If the voltage is set too high, there are 3 possible causes: The voltage regulator is defective. There is excessive drop between alternator, regulator and the battery. The regulator is not grounded properly. To determine if the regulator is grounded properly: Start the engine. Connect a volt meter to the regulator casing and the negative (-) battery post. If the reading is above 0.10 volts, then the regulator is not grounded properly. Clean, and re-test.

12 Positive Side Voltage Drop Connect Volt meter positive (+) red lead to alternator output (+) terminal. Connect Volt meter negative (-) black lead to battery (+) post. With the engine running at 2000 RPM and all accessories ON except rear window defroster. Maximum volt range should be 0.5. If the reading is higher, make sure that all connections between the alternator and the battery are clean and tight. Bat(+) Junction box (solenoid or relay)

13 Negative Side Voltage Drop Connect Volt meter negative (-) black lead to the alternator case. Connect Volt meter positive (+) red lead to battery (-) post. With the engine running at 2000 RPM and all accessories ON except rear window defroster. Maximum volt range should be 0.2 volts for this test. If the reading is higher, connections must be cleaned and tightened or replace as required. If the alternator is equipped with a separate ground strap, be sure to check for voltage drop across it also. Junction box (solenoid or relay)

14 Checking for Unwanted Draw This test is only required if the battery keeps running down after sitting for a day or two. Parasitic Draw? Turn off everything, no lights, no doors open and the key in the off position. Disconnect the battery (-) cable and attach an amp meter ( set to milliamp scale ) in between the clamp and the battery post ( See diagram below). Temporarily install a 12 gauge wire between the battery (-) cable and the battery (-) post. Turn the key to the on position for 10 seconds (Do not start the engine). Turn the key off, close the door and remove the temporary wire. The meter should now have a milliamp reading. The reading should not read more than 50mA, or about 0.05 amps. Fuse Box