ALTERNATOR GP-CHARGING 3469824 - Caterpillar

All Caterpillar Truck EnginesThis article identifies the external terminal locations on alternators that are supplied by various manufacturers and used with Caterpillar engines. Note the characteristics of each of the different terminal patterns and use this information as an aid to servicing alternators.
Illustration 1. Bosch 6N9294 (35 Amp) and 5S9088 (50 Amp) Alternator.There are four illustrations of terminal locations for the 6N9294 (35 Ampere) and the 5S9088 (50 Ampere) Alternators. These are shown in Illustrations 1 through 4.
Bosch®, Nippondenso®, and Delco-Remy® alternators contain three main external terminals: positive output, negative output and "R" terminals. Output for battery charging and for electrical accessories is taken from the positive terminal. The negative terminal is connected to ground.
In some instances, an external power source is required to restore the residual magnetic field in the alternator. An explanation is in Truck Engine News, July, 1986, Page 2 "Brushless Alternators May Not Charge In Certain Conditions ". This is accomplished by using the "R" terminal on the Nippondenso and Delco-Remy alternators and the "D+" terminal on the Bosch alternator. Also, the " R" terminal on all of the examples may be used as an auxiliary terminal; for example, to power a tachometer.
Illustration 2. Nippondenso 6N9294 (35 Amp) and 5S9088 (50 Amp) Alternator.The Motorola® alternators shown in Illustration 5 are used primarily in truck, industrial and marine engine applications.
Illustration 3. Delco-Remy, 35 Amp, 6N9294 Alternator.The two main terminals in this example are the positive output and negative output. The stator terminals would be used to power a tachometer.
The following chart details the part number, application, and specifications for the Motorola alternators.
Illustration 4. Delco-Remy, 50 Amp, 5S9088 Alternator.
Illustration 5. Motorola alternator.Dimensions for terminal mounting studs and screws may vary between alternators. However, vehicle electrical wiring will allow for the differences, so all alternators will work with any Caterpillar engine.