pumping plant was installed at Tsuen Wan No. 2 pumping station, pumping to Kwai Chung North service reservoir.
11.64
Procurement of new plant continued for 7 existing and 3 new pumping stations and design work on 3 existing and 4 new stations was in progress. During the year, work was carried out on a total of 29 projects.
ELECTRICAL DIVISION
Chief Engineer:
F.R. THOMAS, C.Eng., M.I.E.E.
General
11.65
The Division is responsible for the maintenance and repair of electrical and instrumentation equipment installed in pumping stations, treatment works, quarters and other locations of the Waterworks Office and for the design, procurement, installation and commissioning of the electrical component of new waterworks plant other than that associated with the Plover Cove Scheme, High Island Water Scheme and Lok On Pai Desalter.
11.66
Assembly, repair and testing of general electrical and instrumentation equipment is undertaken in workshops located in the Hong Kong and Kowloon Waterworks Depots. Specialist workshops are maintained in Sha Tin Treatment Works for the repair, calibration and testing of electronic instrumentation equipment, and in Kowloon Depot for the repair, calibration and testing of electrical metering and protective equipment. Details of routine works carried out by the Division are given in Appendix CC.
Maintenance
11.67 The most important development during the year was the statistical confirmation of the limitation in the reliable life of some high voltage motors. The windings of these machines are insulated with materials which have been in general use until quite recently and which, having once deteriorated, do not lend themselves to restoration.
11.68 Our findings endorsed opinions which had begun to be expressed elsewhere that such high voltage machines, operating in excess of 3.3 kV tend to fail due to insulation deterioration after about 10 years of service whereas the plant they drive has a service life in excess of 20 years. Modern insulating materials are now available, however, which should have a much longer service life.
11.69
Since 1960, nearly 70 high voltage machines have been commissioned, most of which operate at 6.6 kV and above. These machines drive large pumping plant of great strategic importance. Most employ the obsolescent type of winding insulation.
11.70
Thought has therefore been given to the following alternatives: the possibility of revitalising the older insulation; reinsulating existing windings with modern materials; employing patented restoration procedures by contract where possible; and/or setting to work in the Waterworks Office a winding restoration facility employing direct labour.
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