Centinel System – Repair Manual – 013-001   Alternator

WARNING  Batteries can emit explosive gases. To reduce the possibility of personal injury, always ventilate the compartment before servicing the batteries. To reduce the possibility of arcing, remove the negative (-) battery cable first and attach the negative (-) battery cable last.

WARNING  Acid is extremely dangerous and can damage the machinery and can also cause serious burns. Always provide a tank of strong soda water as a neutralizing agent when servicing batteries. Wear goggles and protective clothing to avoid serious personal injury.

Systems that are 24 VDC must be connected into a temporary 12 VDC configuration.

Attach the carbon-pile and clip-on ammeter as shown.

Adjust the load from the carbon-pile tester to the rated performance of the alternator.

Measure the voltage drop in both the positive and negative circuits.

Add these together and compare the sum to the table below.

Repair or replace the wiring as required to meet the above specifications.

Attach the multimeter to the alternator as shown in the illustration.

With the batteries in a fully charged condition and all the accessories off, start the engine and run it at high idle.

Allow time for the voltage to stabilize before taking any readings.

Measure the alternator output voltage.

Repair or replace the alternator or regulator if the voltage limit exceeds the value in the table.

Refer to the manufacturer’s specifications for minimum voltage output.

Connect the carbon-pile tester to the batteries in parallel.

If more than one wire is connected to the alternator output terminal, clamp the ammeter around all wires.

Clamp the induction ammeter around the alternator output wire.

The alternator must be turning at approximate rated speed.

Most heavy-duty alternators are rated at 5000 rpm. Check the manufacturer’s specifications for the specific alternator being tested.

Make sure that all vehicle electrical loads are turned off.

Start the engine and operate at high idle.

Check the speed of the alternator using a digital optical tachometer. A slipping alternator drive belt can result in a low output reading. The alternator output is directly related to the speed it is turning.

Turn on the carbon-pile tester and adjust until the ammeter reaches its highest reading. Record this value.

Turn off the carbon-pile tester and shut off the engine.

If reading on the ammeter is zero (no output), magnetize the rotor with the alternator hooked up normally.

Momentarily connect a jumper lead from the battery positive (+) to the alternator relay (R) or indicator (I) terminal.

This procedure applies to both negative (-) and positive (+) ground systems, and will restore the normal residual magnetism.

Repeat the test. If the output is still zero, replace the alternator.

If the alternator output is not within 10 percent of the rated output (stamped on the alternator case), replace the alternator.

WARNING  Batteries can emit explosive gases. To reduce the possibility of personal injury, always ventilate the compartment before servicing the batteries. To reduce the possibility of arching, remove the negative (-) battery cable first and attach the negative (-) battery cable last.

• Remove the battery cables.
• Remove the electrical connection from alternator.
• Remove the cooling fan drive belt. Refer to Procedure 008-002.

WARNING  Batteries can emit explosive gases. To reduce the possibility of personal injury, always ventilate the compartment before servicing the batteries. To reduce the possibility of arcing, remove the negative (-) battery cable first and attach the negative (-) battery cable last.

• Disconnect the battery cables.
• Disconnect the electrical connections from the alternator.
• Remove the alternator drive belt. Refer to Procedure 013-005.

Remove the four alternator mounting capscrews.

Remove the alternator from the alternator spacers.

Loosen the alternator support link capscrews.

Remove the support link capscrew from the alternator.

Remove alternator to alternator support capscrews, nut, washer, and alternator.

Inspect the alternator pulley for cracks or broken grooves.

Replace if pulley is damaged.

Install the alternator and the four mounting capscrews.

No alignment is required for the alternator to the alternator bracket.

Install the alternator, capscrew, washer, and nut to the alternator mounting bracket. Tighten the nut.

Install the adjusting link and mounting capscrews. Tighten the capscrews.

WARNING  Batteries can emit explosive gases. To reduce the possibility of personal injury, always ventilate the compartment before servicing the batteries. To reduce the possibility of arcing, remove the negative (-) battery cable first and attach the negative (-) battery cable last.

• Install the cooling fan drive belt. Refer to Procedure 008-002.
• Install the electrical connection to alternator.
• Install the battery cables.

WARNING  Batteries can emit explosive gases. To reduce the possibility of personal injury, always ventilate the compartment before servicing the batteries. To reduce the possibility of arcing, remove the negative (-) battery cable first and attach the negative (-) battery cable last.

• Install the alternator drive belt. Refer to Procedure 013-005.
• Install the electrical connections to the alternator.
• Connect the battery cables.