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 1. All cables, connections, wires, bus-bars are to be carefully examined for any. 2. Check all nuts, bolts, and cable connections for tightness, all loose connections are to be retightened. 3. Circuit breaker contacts to be examined for arcing or contact defects. 4. 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 5. Means of securing cable entering or terminating in or near the switchboard are to be examined and any loose clips are to be replaced. 6. Cables are to be checked for signs of burning or deterioration. 7. Cleaning of the switchboard is to be done with dry compressed air and/or vacuum cleaner. Chemical solvents should not be used. 8. 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. ① Voltage High/Low Alarm/Trip ② Frequency High/Low Alarm/Trip ③ Over-current Alarm/Trip ④ Reverse Power Alarm/trip ⑤ Black out.

3. Alternator Overhaul  The work needs to be done by the yard. A. Allow to open, clean and inspect. B. Record air gap readings. C. Check all fittings/connections for tightness. D. Inspect and clean exciters

4. Boiler Feed Fan Motor O/H ① The motor to be electrically disconnected and the coupling removed. ② 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. ③ 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 ④ Any damage or defective readings are to be reported to the Owner’s Representative ⑤ Following satisfactory testing the motor is to be reassembled using new, yard-supplied bearings-“State brg nos.”-and installed on board on its mounting.

WORDS  Reconditionvt. 修理, 翻新  modify vt. 改装，改进  staging n. 脚手架，工作台  terminating n. 端接 ; 终端  clip n. （线）夹  deterioration n. 老化，变质  solvent n. 溶媒, 溶剂  Disruptionn. 中断  megger n. 高阻表  service n. 维修、保养  proprietary adj. 专卖的，专利的

Phrases  regulatory representative 行政执法部门代表  lump sum 总额，一笔总付的钱  circuit breaker contact 断路开关 / 断路器接点  distribution panel 配电盘  voltage high/low alarm/trip 电压高 / 低警报 / 跳闸  frequency high/low alarm/trip 频率高 / 低警报 / 跳闸  over-current alarm/trip 电流过载警报 / 跳闸  reverse power alarm/trip 逆功率警报 / 跳闸  black out 全船失电  foundation bolt 地脚螺栓  to be dynamically balanced 动态平衡试验

Assignment  1. Review the text.  2. Do the exercises on Page 270.