BOYS' OWN COLUMN.

Auckland Star, Volume LX, Issue 182, 3 August 1929, Page 2 (Supplement)

BOYS' OWN COLUMN.

TRIP TO MIGHTY ARAPUNI. A TRIBUTE TO MODERN ENGINEERING SKILL. Dsar Boys,— Last week-end I motored through tc Arapuni to again visit the scene ■ of a wonderful engineering feat. On two previous occasions had been there —just before f»nd just after the completion of the dam which diverts the Waikato River into its eld bed, where it flowed thousands of years ago, and which has banked up the waters until they form a lake over twenty miles long. This time, however, my attention was directed main.y to the power . house, which, now nearing completion, is supplying power to supplement the Kii s's wharf station. From the spillway 120 feet above the turbines in the station great pipes, 16 feci; ir, diameter, convey the water which is the motive force for the turbine. The water in these pipes runs through the earth at an angle of nearly 45 degrees, so it can be imagined wliat an enormous pressure it exerts on the fan blades of the turbine. The combined weight of the turbine and generator e:;ceed 300 tons, and stand between 30 and 40 feet high. Running at half full load the one machine in operations was generating 10,000 hor3e power. The currcnt leaves the machine at 11,000 volts, and is carried underground by heavy cables to the outdoor sub-riaiica 110 feet above the power house, where it is stepped up to 110,000 volts for the transmission to the Penrose sub-station. The instrument room of the station is a tribute to the progress of the engineers of the world. A huge panel running the full length of the room carrics the instruments which record all information regarding the actual capacity of any machine. The switch gear is of the "remote control type, i.e., all the switches that carry the high tension current are operated by email clectric motors, and these motors are operated through the control beard, which is placed at one end of the station. A most interesting instrument is the automatic device which records the temperatures. Mounted on the panel directly underneath the instrument are numerous push buttons, which, when pressed, connect the inslruii.c:.! to the part of the machine of which the temperature is required, so that by pressing each button in turn the operator can log the temperatures of the machine throughout its inary different parts. Mighty Arapuni is a name of time given to this most modern hydroelectric scheme, and none could fit it better. Truly man has risen to great heights when he can harness Nature and produce energy on such a ■ wholesale scale as at Arapuni.