D—4

Electrodes, were installed on No. 5 pipe-line and the salt velocity method utilized in efficiency tests on No. 5 machine. Both machines have been, out of service for minor repairs, cleaning, and general maintenance. Operation -gave complete satisfaction. Generator-running times were as follows for the year:—

MamgaJioo>.—Rainfall at No. 1 dam was above average and well distributed over the year. This made maintenance of roads continuous, though there was only one large slip. Rainfall for year was: No. 1 dam, 198-05 in.; No. 2 dam, 134-77 in.; No. 3 dam, 100-00 in.; Power-house, 50-02 in. Inspection of part of inside of pipe-lines was made and the surge chamber cleaned out. Painting of outside of pipes was carried out as weather conditions permitted. Due to lack of suitable new turbine buckets during the year and rapid deterioration of original cast-steel ones, a considerable amount of bucket changing and repairing h]ad to be done. The situation has been relieved only to a very small extent by the recent receipt of a new set of bronze buckets which have been fitted to No. 4 turbine. Many of those released are unfit for further service. The extent to which Mangahao has been used is shown by the yearly load factor of 68 per cent, on a maximum load of 20,900 kW. The generator-running times were as follows:

(b) Transmission and Distribution Inspections and patrols were regularly carried out throughout the year and maintenance effected as and when required. Lightning again was the predominant cause of transmission faults, but, as in previous years, the very Mgh standard of reliability of supply was maintained.

9

Generator Number. Time on Load. Time Idle. Time Under Repair. Hours. Percentage. Hours. Percentage. Not in Demand (Hours). In Demand (Hours). Tuai 1 5,394 61-5 2,456 28-0 865 45 2 5,474 62-5 2,293 26-2 991 02 3 7,293 83-5 1,242 14-2 225 Piripaua 4 4,810 54-9 3,430 39-1 519 01 5 3,917 44-7 3,227 36-8 1,614 01

Generator Number. Time on Load. Time Idle. Time under Repair. Hours. Percentage. Hours. Percentage. Not in Demand (Hours). In Demand (Hours). 1 8,612 98-3 66 0-8 76 6 2 8,641 98-7 44 0-5 69 5 3 8,664 98-9 36 0-4 54 6 4 8,444 96-4 36 0-4 275 4 5 8,676 99-0 35 0-4 45 4