3306B Industrial Engine Caterpillar

Test Tools For The Electrical System

Most of the tests for the electrical system can be done on the engine. The wiring insulation must be in good condition. The wire and cable connections must be clean and tight. The battery must be fully charged. If the on-engine test shows a defect in a component, remove the component for more testing.

The service manual Testing And Adjusting Electrical Components, REG00636 has complete specifications and procedures for the components of the starting circuit and the charging circuit.

Illustration 1	g00283565
4C-4911 Battery Load Tester

The 4C-4911 Battery Load Tester is a portable unit in a metal case. The 4C-4911 Battery Load Tester can be used under field conditions and under high temperatures. The tester can be used to load test all 6, 8, and 12 Volt batteries. This tester has two heavy-duty load cables that can easily be fastened to the battery terminals.

A load adjustment knob is located on the top of the tester. The load adjustment knob permits the current that is being drawn from the battery to be adjusted to a maximum of 1000 amperes. The tester is cooled by an internal fan that is automatically activated when a load is applied.

The tester has a built-in LCD. The LCD is a digital voltmeter. The LCD is a digital meter that will also display the amperage. The digital voltmeter accurately measures the battery voltage at the battery. The LCD uses tracer wires to measure this battery voltage. The tracer wires are buried inside the load cables. The digital meter, that displays the amperage, accurately displays the current that is being drawn from the battery which is being tested.

Note: Refer to Operating Manual, SEHS9249 for more complete information for the use of the 4C-4911 Battery Load Tester .

The 8T-0900 Ammeter is completely portable. This ammeter is a self-contained instrument that measures electrical currents without breaking the circuit and without disturbing the conductor's insulation.

Illustration 2	g00296441
8T-0900 Ammeter

The ammeter contains a digital display that is used to monitor current directly within a range between 1 ampere and 1200 amperes. If an optional 6V-6014 Cable is connected between this ammeter and a digital multimeter, current readings can be viewed directly from the display of the multimeter. This can be accomplished under only one condition:

• The readings are less than 1 ammeter.

A lever opens the ammeter's jaws over a conductor. The conductor's diameter can not be larger than 19 mm (.75 inch).

The spring loaded jaws close around the conductor for measuring the current. A trigger switch controls the ammeter. The trigger switch can be locked into the ON position or into the OFF position.

After the trigger has been working and the trigger is turned to the OFF position, the reading appears in the digital display for five seconds. This accurately measures currents in areas with a limited access. For example, these areas include areas that are beyond the operator's sight. For DC operation, an ammeter contains a zero control, and batteries inside the handle supply the power.

Note: Refer to Special Instruction, SEHS8420 for more information about using the 8T-0900 Ammeter.

Illustration 3	g00283566
6V-7070 Digital Multimeter

The 6V-7070 Digital Multimeter is a portable, hand-held service tool with a digital display. This multimeter is built with extra protection against damage in field applications. The multimeter is equipped with seven functions and 29 ranges. The 6V-7070 Digital Multimeter has an instant ohms indicator. This indicator permits checking continuity for a fast inspection of the circuits. The multimeter can also be used for troubleshooting capacitors that have small values.

Note: Refer to Special Instruction, SEHS7734 for complete information for the use of the 6V-7070 Digital Multimeter .

Battery

Show/hide table

Never disconnect any charging unit circuit or battery circuit cable from the battery when the charging unit is operated. A spark can cause an explosion from the flammable vapor mixture of hydrogen and oxygen that is released from the electrolyte through the battery outlets. Injury to personnel can be the result.

The battery circuit is an electrical load on the charging unit. The load is variable because of the condition of the charge in the battery.

Use the 4C-4911 Battery Load Tester to test a battery that does not maintain a charge when the battery is active. Refer to Operating Manual, SEHS9249 for detailed instruction on the use of the 4C-4911 Battery Load Tester. See Special Instruction, SEHS7633 for the correct procedure and for the specifications to use when you test the batteries.

Charging System

The condition of charge in the battery at each regular inspection will show if the charging system operates correctly. An adjustment is necessary when the battery is constantly in a low condition of charge or a large amount of water is needed. A large amount of water would be more than one ounce of water per cell per week or per every 100 service hours.

When you have an opportunity, test of the charging unit and voltage regulator on the engine:

• Use wiring that is a permanent part of the system.

• Use components that are a permanent part of the system.

Off-engine testing or bench testing offers a test of both the charging unit and voltage regulator operation. This testing will provide an indication of needed repair. After repairs are made, recheck the units to prove that both units have been repaired to the original condition of operation.

To check for correct output of the alternator, see the Specifications module.

For complete service information, refer to Service Manual Module, SENR7503, "Delco Remy 30-SI Series Alternators". This module is part of Service Manual, REGO00636.

Before the start of on-engine testing, the charging system and the battery must be checked according to the following steps.

1. The battery must be at least 75 percent (1.225 Sp Gr) of the full charge. The battery must be held tightly in place. The battery holder must not put too much stress on the battery.

2. Cables between the battery, the starter, and the engine ground must be the correct size. Wires and cables must be free of corrosion. Wires and cables must have cable support clamps in order to prevent stress on battery connections (terminals).

3. The following components that have direct relation to the charging circuit must give correct circuit control:
   • Leads

   • Junctions

   • Switches

   • Panel instruments

4. Inspect the drive components for the charging unit in order to be sure that the components are free of both grease and oil. Be sure that the drive components have the ability to operate the charging unit.

Alternator Regulator

The charging rate of the alternator should be checked when an alternator is charging the battery too much. The charging rate of the alternator should be checked when an alternator is not charging the battery enough. Make reference to the Specifications module in order to find all testing specifications for the alternators and regulators.

No adjustment can be made in order to change the rate of charge on the alternator regulators. If the rate of charge is not correct, a replacement of the regulator is necessary.

Tightening The Alternator Pulley Nut

Illustration 4	g00283568
Tools for Tightening the Alternator Pulley Nut (1) 8T-9293 Torque Wrench. (2) 8S-1588 Adapter (1/2 inch female to 3/8 inch male). (3) 2P-8267 Hex Bit Socket. (4) 8H-8517 Combination Wrench (1-1/8 inch). (5) 8T-5314 Adapter Socket .

Tighten the nut that holds the pulley with the tools shown. Refer to the Specifications, "Alternators and Regulators" module for the torque.

Electric Starting System

Use the multimeter in the DCV range to find starting system components which do not function.

Move the start control switch in order to activate the starting solenoids. The starting solenoid's operation can be heard as the pinions of the starting motors are engaged with the ring gear on the engine flywheel.

If a solenoid for a starting motor will not operate, it is possible that the current from the battery did not reach the solenoid. Fasten one lead of the multimeter to the connection (terminal) for the battery cable on the solenoid. Put the other lead to a good ground. A zero reading indicates that there is a broken circuit from the battery. More testing is necessary when there is a voltage reading on the multimeter.

The solenoid operation also closes the electric circuit to the motor. Connect one lead of the multimeter to the solenoid connection (terminal) that is fastened to the motor. Put the other lead to a good ground. Activate the starting solenoid and look at the multimeter.

A reading of the battery voltage shows that the problem is in the motor. The motor must be removed for further testing. A zero reading on the multimeter shows that the solenoid contacts do not close. This is an indication of the need for repair to the solenoid or an adjustment to be made to the starting motor pinion clearance.

Perform a test. Fasten one multimeter lead to the connection (terminal) for the small wire at the solenoid and fasten the other lead to the ground. Look at the multimeter and activate the starting solenoid. A voltage reading shows that the problem is in the solenoid. A zero reading indicates that the problem is in the start switch or the wires for the start switch.

Fasten one multimeter lead to the start switch at the connection (terminal) for the wire from the battery. Fasten the other lead to a good ground. A zero reading indicates a broken circuit from the battery. Make a check of the circuit breaker and wiring. If there is a voltage reading, the problem is in the start switch or in the wires for the start switch.

Starting motors that operate too slowly can have an overload because of too much friction in the engine that is being started. Slow operation of the starting motors can also be caused by a short circuit, loose connections and/or dirt in the motors.

Starting Motor Adjustments

Pinion Clearance Adjustment

When the solenoid is installed, make an adjustment of the pinion clearance. The adjustment can be made with the starting motor removed.

Illustration 5	g00283572
Connection For Checking Pinion Clearance (1) Ground terminal. (2) SW terminal. (3) Connector.

1. Install the solenoid without connector (3) from the MOTOR connections (terminal) on the solenoid to the motor.

2. Connect a battery, that has the same voltage as the solenoid, to the "SW" terminal (2) .

3. Connect the other side of the battery to connector (3) .

4. For a moment, connect a wire from the solenoid connection (terminal), which is marked "MOTOR", to the ground connection (terminal). The pinion will shift to the crank position and the pinion will stay there until the battery is disconnected.

Show/hide table



Illustration 6	g00283574
Pinion Clearance Adjustment (4) Shaft nut. (5) Pinion. (6) Pinion Clearance.

5. Push the pinion toward the end with the commutator in order to remove free movement.

6. Pinion clearance (6) must be 8.3 to 9.9 mm (.33 to .39 inch).

7. In order to adjust the pinion clearance, remove the plug and turn the shaft nut (4) .

Solenoid Position Adjustment

The solenoid position on the starting motor controls the pinion clearance. If the solenoid position's dimension is correct, the pinion clearance is correct. The adjustment can be made with the starting motor removed. Follow this procedure for the solenoid position adjustment.

1. Check the distance between the intermediate housing and the solenoid bracket.

2. If the distance is not correct, loosen the bolts and move the solenoid until the distance is correct. The bracket has elongated holes.

3. After the adjustment is correct, tighten the bolts to a torque of 7 ± 10 N·m (5 ± 7 lb ft).

Armature End Plate Adjustment

The armature end plate adjustment is made during assembly of the starting motor.

Illustration 7	g00322864
Starting Motor End Cover (1) Plug. (2) Spacer. (X) Distance between armature and face of end cover. (Y) Length of plug threads.

1. Remove center plug (1) and spacer (2) from the end cover.

2. Force the armature assembly into the drive housing up to the spacer.

3. Measure distance (X) from the end cover to the armature assembly.

4. Measure length of threads (Y) of plug (1) .

5. Subtract measurement (Y) from measurement (X) .

   This difference is the armature end play. The allowable end play is 0.004 ± 0.12 mm (.0002 ± .0047 inch). The end play can be adjusted with different spacers (2). A list of the spacers' thicknesses follows:

   1.5 mm (.059 inch)

   1.7 mm (.067 inch )

   1.9 mm (.075 inch)

   2.1 mm (.083 inch)

   2.3 mm (.090 inch)

   2.5 mm (1.00 inch)

6. Install correct spacer (2). Put 9S-3263 Thread Lock Compound onto the threads of plug (1). Install plug (1) into the end cover.