Official Guide to the Government Court: N.Z. Centennial Exhibition
The function of the Hydro-Electric Branch of the Public Works Department is to develop the water-power resources of the country, and the exhibit is designed to illustrate these activities.
The main feature of the exhibit is a model of the Arapuni Power Development. Push buttons are provided near the model to enable the onlooker, should he so desire, to hear a recorded lecturette explaining the model, while the regions being described are automatically lighted and certain of the parts automatically moved to illustrate the manner in which they work.
The conversion of water-power to mechanical energy is symbolised by a large rotating, aluminium turbine runner, the path of the water into the runner being symbolised by a mural painting of swirling waters. In addition there is exhibited a full-size replica of one of the Pelton wheels in use at Mangahao Power Station.
One result of unified control in the development of hydro-electric power has been the standardisation of voltage and frequency throughout New Zealand, so that an electrical appliance bought anywhere in New Zealand may be used anywhere else in New Zealand. This is illustrated by a large electric clock driven from the ordinary supply mains. In the background, through the glass clock, may be seen the master clock, which is normally situated at the power station, and by which the frequency of the supply is controlled. All synchronous clocks, no matter where they are situated, show the same time as the master clock, in proof of which the observer may see the I sweep second hands on the large clock and on the master clock pass the 12 o'clock mark at the same instant in smooth, continous motion.
A panoramic photomural shows an extensive view of the Waitaki power development, and below this a series of transparencies of the construction of one of the dams on the Mangahao River show the stages by which the rivers are conquered so that their energies can be turned to use in the service of man.
The conquest of distance by the transmission of power is depicted among the murals in the exhibit.