Lesson33electricalrepairwork.pptVIP

Lesson 33 Electrical Repair Work CONTENTS 1. Main Switchboard Cleaning 2. ACB Maintenance 3. Alternator Overhaul 4. Boiler Feed Fan Motor O/H 1. Main Switchboard Cleaning All cables, connections, wires, bus-bars are to be carefully examined for any. Check all nuts, bolts, and cable connections for tightness, all loose connections are to be retightened. Circuit breaker contacts to be examined for arcing or contact defects. Main switchboard holding down bolts and all equipment securing bolts are to be checked for tightness. The following work to be carried out by the yard. 1. Main Switchboard Cleaning Means of securing cable entering or terminating in or near the switchboard are to be examined and any loose clips are to be replaced. Cables are to be checked for signs of burning or deterioration. Cleaning of the switchboard is to be done with dry compressed air and/or vacuum cleaner. Chemical solvents should not be used. After cleaning all moving parts are to be carefully lubricated. 2. ACB Maintenance The following trips will be tested in the presence of Surveyor after overhaul. Voltage High/Low Alarm/Trip Frequency High/Low Alarm/Trip Over-current Alarm/Trip Reverse Power Alarm/trip Black out. 3. Alternator Overhaul The work needs to be done by the yard. Allow to open, clean and inspect. Record air gap readings. Check all fittings/connections for tightness. Inspect and clean exciters 4. Boiler Feed Fan Motor O/H The motor to be electrically disconnected and the coupling removed. Motor to be dismantled, end-covers bearings removed and all parts thoroughly cleaned for inspection. The windings are to be megger tested and the value obtained recorded in the overhaul record sheet. The stator windings are to be dipped in insulating varnish and baked hard and a second set of megger readings taken and recorded. 4. Boiler Feed Fan Motor O/H Any damage or defective readings are to be reported to the Owner’s Representative Following satisfactory testing the motor