T1 Alternator Output - Test
- Fully charged batteries have open circuit voltage above 12.5 V on 12 V systems or 25 V on 24 V systems.
- If the batteries are fully charged, then crank the engine for 30 seconds. This action reduces the battery voltage. Operate the lights for 10 minutes while the engine is off as an alternative.
- Connect the 9U-5795 Current Probe to a DMM (digital multimeter) or use the 225-8266 Ammeter Tool Gp . The multimeter must have a peak hold feature. Clamp the probe around alternator output wire "B+". Before you clamp the probe around the wire, ensure that the probe is "zeroed" .
- Set the digital multimeter to "peak hold" or "max mode" on the "mV" scale.
- Turn on all electrical accessories: lights, air conditioning and radio.
- Start the machine, and immediately set the throttle to at least 75%. The peak current will appear on the voltmeter in "peak hold" or "max" mode.
Expected Result: This current reading should be at least 90% of the specified peak output.
Results:
- OK - The current is at least 90%. For 85 amp alternators, the current should be over 76 A. For 75 amp alternators, the current should be over 67 A. For 50 amp alternators, the current should be over 45 A. Go to Testing and Adjusting, "T2 Electrical System Current - Test".
- NOT OK - The current is less than 90%. Go to Testing and Adjusting, "T4 Alternator Drive System - Check".
- OK - The current is at least 90%. For 85 amp alternators, the current should be over 76 A. For 75 amp alternators, the current should be over 67 A. For 50 amp alternators, the current should be over 45 A. Go to Testing and Adjusting, "T2 Electrical System Current - Test".
Caterpillar Information System:
3512B Marine Auxiliary Engine Fuel Conservation Practices
3512B Marine Auxiliary Engine Before Starting Engine
26SI Series Alternator Normal Operation
On-Highway Engines Electronic PTO Installation and Application Guide Switches
3512B Marine Auxiliary Engine Cooling System Operation
3406E On-Highway Engine Boost Pressure Sensor - Remove and Install
3406E On-Highway Engine Inlet Air Temperature Sensor - Remove and Install
3406E On-Highway Engine Atmospheric Pressure Sensor - Remove and Install
3406E On-Highway Engine Fuel Temperature Sensor - Remove and Install
3406E, C-10, C-12, C-15, C-16 Truck Engines Serial Number Plate
26SI Series Alternator Component Description
3406E On-Highway Engine Engine Support (Front) - Remove and Install
26SI Series Alternator T2 Electrical System Current - Test
26SI Series Alternator T3 Charging System - Test
26SI Series Alternator T4 Alternator Drive System - Check
26SI Series Alternator T5 Alternator Current - Test
26SI Series Alternator T6 Residual Magnetism Restoration
26SI Series Alternator T7 Identifying Source of Current Draw - Test
26SI Series Alternator T8 Alternator Overcharging - Test
26SI Series Alternator Initial Troubleshooting Procedure
3512B Engine Engine Oil and Filter - Change
26SI Series Alternator General Information
26SI Series Alternator Component - Test
26SI Series Alternator Alternator - Assemble