ARBST Generator Test

ARBST Generator Test:

The following procedure is outlined step-by-step on the ARBST screen.

NOTE: Disconnect ARBST battery charger prior to turning ARBST on.

CAUTION: SAFETY GLASSES SHOULD BE WORN AND RINGS, WATCHES, AND ALL OTHER HAND JEWELRY SHOULD BE REMOVED.

1. Verify the fusible link between the starter and generator is good. Also verify connections are tightened to specification and clean. (Charging system light functional test will verify link is ok.)

IMPORTANT: If a fusible link is blown, don't just replace it. The most probable cause of a blown link is an internal generator failure. Verify that there is no external arcing or shorting of fusible link with other wires and/or components. If no problems are found, replace generator.

2. Turn ARBST Tester on. Connect large red ARBST tester cable to battery positive (+). Connect large black ARBST tester cable to battery negative (-). Place gray inductive current pick-up around battery positive (+) cable. Make sure that the arrow on the gray inductive current pick-up is pointing toward the starter motor solenoid.
3. Place the gray inductive current pick-up around the battery positive cable between the battery positive terminal and the starter motor solenoid connection. The easiest place to connect the inductive pick.up is next to the brake master cylinder. The battery positive cable runs under the master cylinder and is covered by a protective wire conduit. This conduit does not need to be removed for this test. On vehicles equipped with ABS brakes, pick-up can be placed between the ABS master cylinder and starter motor.
4. Press CHARGING SYSTEM TEST. The display should show the correct number of cylinders. To change the number of cylinders, simply press that number on the keypad.
5. Run the engine at 2000 RPM until the display flashes MAINTAIN 2000 rpm.
6. Hold at 2000 rpm until the counter counts down from ten seconds.
7. When ten seconds are over, run the engine at idle until the display says MAINTAIN IDLE. Hold this for a few seconds until the display says TEST COMPLETE. Turn the engine off. Press CONTINUE to see the results.

Results
The ARBST tester will display the voltage and current output of the generator.

Voltage
- With a good battery in the vehicle, the voltage output should be above 13 volts.

Current

Generator Output:

- All CS series generators should be able to produce within 15 amps of their rated output at 2000 rpm. The Saturn vehicles use an 96 amp CS 130 series generator. Refer to graph for current output.

Diode Pattern
- In general this reading can be ignored on the Saturn vehicles.

If the generator does not pass the above voltage and current tests:
1. Verify the battery is good and charged. (Refer to ARBST test for battery.)
2. Verify the vehicle does not have any excessive electrical loads.
3. Replace the generator.
4. Perform the ARBST generator test to verify the repair.
The output of the generator is dependant on the demand (load), vehicle temperature, and the rpm of the generator.

Generator Output:

LOAD: If the vehicle electrical demand is low (all accessories off), the output from the generator will be low. As the demand increases (accessories on) the generator output will increase.

TEMPERATURE: As the temperature increases the output from the generator decreases.

RPM: The generator rpm is 2.57 times the engine rpm. As rpm increases the output of the generator increases until it reaches maximum output (generator fully loaded). At extended idle (low rpm), maximum load, and high temperatures the generator maximum output will be around 30 amps.

IMPORTANT: When testing a generator, the load, temperature and rpm must be considered to obtain the most accurate conclusion. When using the ARBST or a carbon pile tester (carbon pile fully On), the load will be approximately maximum load.