PLATE 6N9369 - Caterpillar

Illustration 1 g00824471
M1 Series Alternator
Illustration 2 g00824534
HDB Series AlternatorThe alternator is an electromechanical component that converts mechanical energy into electrical energy. The alternator charges the storage battery during engine operation and the alternator supplies power for the machine electrical systems. The alternators are heavy duty and the alternators are brushless.The M1 series alternators have 35 amp outputs and 50 amp outputs. The HDB series alternators have 50 amp outputs, 65 amp outputs, 80 amp outputs, and 95 amp outputs. Illustrations in this manual show the 35 amp alternator and the 65 amp alternator. Differences between the alternators are noted.The alternator is divided into a front frame and a rear frame. The alternator contains parts that are inside of the frames. The stator, the field winding, the rectifier, and the regulator are stationary parts. The stationary parts are bolted to the frames. The rotor is a moving part. The rotor is mounted to the frames by ball bearings or by roller bearings.The field winding uses DC voltage to create a magnetic field. The magnetic field magnetizes the rotor. The rotor rotates the magnetic field on the inside of the stator. The stator generates AC voltage. The rectifier changes the AC voltage into DC voltage. Part of the DC voltage returns to the field winding in order to maintain the magnetic field. The remainder of the DC voltage is supplied to the battery and to the electrical components through battery terminals. The regulator limits the DC voltage at the battery terminals to 28 1 volts by controlling the current in the field winding.The alternator also contains parts that are outside of the frames. The removable rear cover provides easy access to many of the internal components for troubleshooting and for repair. A belt (not shown) provides the mechanical energy. The belt is attached to the shaft of the rotor. The fan cools the inside of the alternator. Air is drawn through baffles in the rear cover. The air exits from the front frame that is behind the fan.The battery terminals provide the alternator output. The "B+" terminal is connected to the rectifier. The "B-" terminal of the M1 series alternator is isolated from the case and the terminal is connected to the rectifier. The "B-" terminal of the HDB series alternator is connected to the case.The "R" terminal is located between the battery terminals. The "R" terminal is used to restore the residual magnetism of the alternator. This terminal may be used by one of the following components:
A Charge Indicator
A Tachometer
VIMS, CMS, EMS, etc.
An Hour Meter