TRACK 1466062 - Caterpillar

System Operation
Generator ECM (14) and machine ECM (24) communicate through the CAN"A" and the CAN"C" lines. Displays (11) and (13) communicate with the ECMs through CAN"A".Machine ECM (24) operates with generator ECM (14) to monitor and control the operation of the generator system. The machine ECM determines via CAN whether the accessory power inverter is installed on the tractor. The machine ECM communicates with the screed heat ECM to determine the power demands for screed heating.Machine ECM (24) monitors engine speed. When engine speed is greater than 400 rpm, the machine ECM determines that the generator is ready to produce power. In this case, the display screens update to show the screed heat switch and, when installed, the accessory power inverter switch.When the screed heat switch or the accessory power inverter switch is activated, machine ECM (24) generates an enable request for the generator. The request signal is sent to generator ECM (14).Generator ECM (14) monitors and controls the operation of the generator and the inverter. The generator does not produce voltage unless the generator is enabled by the generator ECM. The generator ECM receives an enable signal from machine ECM (24) when generator power is requested.Generator ECM (14) enables the generator when the screed heaters are activated or when the accessory power inverter is activated. When the screed heat response is set to"quick heat", machine ECM (24) can modify engine speed to provide more generator power as required.Generator ECM (14) communicates the total available power at the current engine speed to machine ECM (24). The machine ECM reserves power for the accessory power inverter (when installed) and communicates the remaining power available to the screed ECM for screed heating.
Illustration 2 g06058800
Switched Reluctance Inverter
(25) Capacitor
(26) Power transistor
(27) Diode
(28) To phase windings
(29) Bleed-down resistor
(30) Frame balance resistors
(31) DC bus connectors
(32) Bus shift resistorInverter (15) works together with generator (16) and generator ECM (14) as a system to provide a constant DC bus voltage. The inverter also contains the hardware for the insulation monitoring system.Inverter (15) provides precisely timed excitation voltages to generator (16). These excitation voltages enable the generator to produce electrical power. The inverter also converts pulsed direct current from the generator into direct current for the screed heat system and accessory power inverter (19).Power transistors (26) are controlled by generator ECM (14). The transistors are used to excite the three phases of the generator in a precisely timed sequence. When a phase winding is in the excitation phase, control voltage is applied to the base of the transistor. In this case, the transistor is active and current can flow across the transistor. Under these conditions, the DC bus voltage is transmitted to corresponding phase windings (28).When a phase winding is in the generation phase, the corresponding power transistors are deactivated. Voltage returning from the phase windings is directed through diodes (27) to DC busses (31). Capacitor (25) stores the energy and helps to maintain the DC busses at a constant voltage.Bleed-down resistor (29) continuously dissipates a small amount