Safety - Section 20 OM2044 Page 20-20 SPECIAL PRECAUTIONS FOR WORKING ON AN 830E-AC TRUCK Preliminary Procedures before Welding or Per- forming Maintenance Engine Shutdown Procedure before Welding or Performing Maintenance Prior to welding and/or repairing an 830E-AC dump truck, maintenance personnel must attempt to notify a Komatsu service representative. Only qualified per- sonnel, specifically trained for servicing the AC drive system, must perform this service. Normal operation of the drive system at shutdown will leave the system safe to maintain.
However, in the event of a system failure, performing the follow- ing procedure prior to any maintenance activities will ensure that no hazardous voltages are present in the AC drive system. If it is necessary to perform welding or repair to the truck without the field engineer present, the following procedures must be followed to ensure that the truck is safe for maintenance personnel to work on and to reduce the chance for damage to equipment. 1. Before shutting down the engine, verify the sta- tus of all the drive system warning lights on the overhead display panel. Use the lamp test switch to verify that all lamps are functioning properly.
If any of the red drive system warning lights remain on, DO NOT attempt to open any cabi- nets, disconnect any cables, or reach inside the retarder grid cabinet without a trained drive sys- tem technician present - even if engine is off. Only qualified personnel, specifically trained for servicing the A-C drive system, must perform this service. Anytime the engine is operating: DO NOT open any of the cabinet doors or remove any covers. DO NOT use any of the power cables for hand holds or foot steps. DO NOT touch the retarding grid elements. 2. If all red drive system warning lights are off, fol- low all of the instructions for “Parking The Machine.” 3.
After the engine has been off for at least five minutes, inspect the link voltage lights on the exterior of the main control cabinet and rear of the center console. If all lights are off, the retard grids, wheel motors, alternator, and related power cables are safe to work on. Before opening any cabinets or touching a grid element or a power cable, the engine must be shutdown and the red drive system warning lights must not be illuminated. 4. Locate the GF cut-out switch in the front access panel on the left side of the main control cabi- net. Place the switch in the CUTOUT position.
This will prevent the alternator from re-energiz- ing and creating system voltage until the switch is returned to the previous position. 5. Ensure both battery disconnect switches are in the OFF position. Verify that the battery discon- nects are functioning. 6. Before doing any welding on the truck, always disconnect the battery charging alternator lead wire.