PLATE 9T5505 - Caterpillar

The Electric Screed Heating System and the Accessory Power Inverter will contain hazardous voltage levels during machine operation. Normally, this voltage will dissipate quickly after a short period of time after machine shutdown, but potentially could take longer. Always perform the “Electrical Shutdown and Voltage Discharge” Procedure in the Service Manual before performing electrical service on the Electric Screed Heating System and the Accessory Power Inverter.Failure to follow these instructions could result in personal injury or death.
In order to avoid the build up of hazardous live voltages on the exposed surfaces, all grounding wires must be properly connected at all times during engine operation.Any disconnected grounding wires (including the grounding bond wires, the conductor shield wires, the power inverter grounding straps and the component housing grounding straps) must be properly reconnected before the engine is started.Failure to follow these instructions could result in personal injury or death.
Electrical Shutdown and Voltage Discharge Procedure for Electric Screed Heating System and Accessory Power Inverter
This procedure must be performed when:
An electrical service procedure must be performed on any component in the Electric Screed Heating System and the Accessory Power Inverter after Engine shutdown. Included is opening a hazardous voltage enclosure that houses hazardous voltage connections. Also included is the disconnection of any hazardous voltage cable connectors in the AC system or the DC system.Note: If the engine is still running, be sure that the Generator has been disabled by turning off the Screed Heat and the Accessory Power Inverter (if installed) from the display.
Illustration 1 g03731434
Screed Heat - OFF
Illustration 2 g03731443
Accessory Power Inverter - OFF
Procedure:
Turn the key start switch to the OFF position.
After the Engine has shutdown, turn the key start switch to the ON position. Do not start the Engine.
Illustration 3 g03731417
Voltages on the Display
Use the Display to check the status of the DC Power Bus voltage. See Illustration 3. Confirm the voltage measurements of the “DC Bus Voltage” and “Screed Bus Voltage” are less than 50 VDC. If the voltages are above 50 VDC, monitor until the levels are less than 50 VDC. Once the displayed DC voltages are less than 50 VDC, continue to the next step.
Access the battery disconnect switch assembly located under the access cover on the left enclosure of the machine. Turn the battery disconnect switch to the OFF position and Lock out the switch.
Observe the state of the red Hazardous Voltage System Energized Indicators on the Switched Reluctance (SR) Power Inverter (located under the right enclosure). The indicator is designed to turn OFF when the voltage of the “DC Bus Voltage” is discharged to 50 VDC or less. The indicator should not be illuminated.
If no AC or DC hazardous voltage conductors will be exposed during a procedure, service can now be performed.If an AC connection enclosure is opened or if a hazardous voltage DC connector is disconnected, use a voltage meter to measure DC voltage between any exposed conductors and frame ground. Do not make personal contact with the exposed conductors until the voltage between the conductors and