1.18.3. Alternator/Charqinq Circuits

TM 5-3895-373-20 1.18.3. Alternator/Charqinq Circuits. The alternator/charging circuits consist of the alternator, voltage transformer, and the storage batteries. The alternator is belt driven from the crankshaft pulley on the paving machine engine. Alternating current (AC) is generated as the coils of the rotor pass a pair of magnetic poles in the stator. The AC is rectified to direct current (DC) through a series of diodes, which form a rectifier circuit. Batteries A and B are connected in series to supply 24 V to the 24 V post on the voltage transformer. When the ignition switch is turned on, the field relay closes sending 24 VDC excitation voltage to the alternator D+ terminal for engine initial startup. The 24 V output charging voltage of alternator B+ terminal is directly connected to the 24 V post on the voltage transformer. The 24 VDC output of the voltage transformer is applied to the POS terminal of battery B. Because 12 VDC is applied to the NEG terminal and 24 VDC is sent to the POS terminal, the batteries are charged with a difference of 12 VDC. The voltage transformer simply converts the 24 VDC into 12 VDC to charge the batteries. 1.18.4. Paving Liqhtinq Circuits. Operator control panel lights, instrument lights, and work lights are controlled from the operator gauge panel. Screed control panel lights are controlled from the screed control panels. All paving machine lights are operated by toggle switches. The ignition switch receives power from CB8 through the three emergency stop switches. When in the ON position, the ignition switch supplies 12 VDC power to the panel light switch. Where the panel light switch is in the up, ON position, the operator gauge panel and operator switch panel lights are lit. The gauges on the operator gauge panel also have internal lights that are lit when the panel light switch is ON. 12 VDC from the 80 amp circuit breaker feeds power to the rear work lights through CB9, the auger work lights through CB 10, and the forward work lights through CB 11. Each circuit breaker feeds a toggle switch on the operator gauge panel for independent control of each light. CB6 supplies 12 VDC to the left and right screed control panels for panel lights. The 12 VDC is applied to a toggle switch that controls the panel lights. 1-26