THE TRI-CIRCUIT ALTERNATOR

ALTERNATOR Tri-Circuit THE TRI-CIRCUIT ALTERNATOR The Tri-Circuit alternator consists of a single ring of magnets inside the flywheel, which supplies the magnetic field for a stator having one output lead which produces AC voltage. The output lead connects to a charge lead that contains one diode which rectifies minus -12 volts DC (5 amps at 3600 RPM) for lights. This same charge lead contains a second diode that rectifies plus +12 volts DC (5 amps at 3600 RPM) for battery charging and external loads. See Fig. 205. The alternator uses less than 0.2 horsepower. Fig. 205 - Tri-Circuit Alternator If an accessory such as an electric clutch is used on the equipment, 3.5 amps powers the clutch, and up to 1.5 amps charges the battery, thus not over-charging the battery. A two-pole clutch switch is used on the vehicle when an electric clutch is an accessory. When the clutch is switched on, one circuit is used to engage the clutch, and the other circuit bypasses the resistor, thus allowing full alternator output to be applied to the battery and clutch. Fig. 206 and 207. Fig. 206 - Typical Wiring Diagram Fig. 207 - Typical Wiring Diagram (Cont’d.) If the clutch is not engaged, a resistor is placed in series with the alternator charge lead, thereby limiting the charge current to about 3 amps. See Fig. 207. The resistor (20 watts), becomes hot and must be mounted somewhere on the vehicle by the manufacturer. The battery is not used for the lights, so lights are available even if the battery is disconnected or removed. Current for the lights is available as long as the engine is running. 12 volt lights with a total rating of 60 to 100 watts may be used. With lights rated at 70 watts, the voltage rises from 8 volts at 2400 RPM to 12 volts at 3600 RPM, so the brightness of the light changes with the engine speed. TESTING ALTERNATOR STATOR OUTPUT Connect load lamp to AC (green connector) output plug and ground as shown in Figure 208. Load lamp should light to full brilliance at medium engine speed. If lamp does not light, or is very dim at medium speeds, remove blower housing and flywheel. Disconnect the ground terminal end of AC coil, which is attached to the stator laminations with screw. Fig. 208 - Testing Stator Output 64