Transformer models determine transient voltages

SPACE OCCUPIED BY INSULATION profoundly affects the over-all transformer size and weight, and the cost. The insulation itself is expensive, takes space, and interferes with other functions, as for instance, removal of heat from core and coils, and increases reactance. More important, however, is the fact that additional amounts of copper and iron are required in a transformer because of the space taken up by insulation. For these reasons, in large high-voltage power transformers large dividends, in size, weight, and cost reductions, and in the improvement of some operating characteristics, are obtained by designing the insulation more precisely as to location and amount.