ARAPUNI'S LAST PROBLEM

New Zealand Herald, Volume LXX, Issue 21509, 5 June 1933, Page 8

ARAPUNI'S LAST PROBLEM

The vibration in No. 1 generator at Arapuni has been proved to have been set up by a mechanical cause — the inaccurate weighting of the runner to counterbalance an accidental increase in weight on the other side. Thus, the defect had its origin in the engineering works overseas, and now perhaps New Zealand will no longer be afflicted by theorists, many of them purely laymen, who have asserted with the confidence of their kind that the trouble lay in the foundations of the powerhouse. The vibration problem, which could not be investigated as promptly as needs demanded through the stoppage of the plant because of headrace leakage, was seized upon by the critics of the whole scheme as further proof of their pessimistic contentions which started when the contractors, during the excavation of the powerhouse foundations, relinquished the contract. They refused to accept the opinion of the Public Works Department that foundations, strongly reinforced horizontally, could be laid to carry the generating plant. Although independent engineers gave evidence of such an idiosyncrasy occurring in one generating set of a series in parts of the world where no doubt existed as to the stability of the foundations, persistent propaganda continued, arousing anxiety in many minds as to the permanence of the whole scheme. At last the bogey has been set at rest. The fracture in the headrace was accounted for by an engineer with an international reputation and the area was made watertight after one slight mishap through subsidence. The falls have been made secure against further erosion, by a skin of concrete. Now the problem of the vibration of one set has been solved. In the meantime, Arapuni goes on with its task of national usefulness. The country may now expect the critics to hold their peace. They have been proved to be false prophets.