Small Transformers

       

Further reading

• Small Transformers (2) (3075)
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• Small transformers (4) (2700)

When procuring small transformers, the paramount criterion is often alleged to be the costs, while only the price is meant, not the costs the transformer causes during adaptation, fabrication of the finished device, the cycle of use and the recycling of materials afterwards.

Many a transformer recycled now may bring more profit via scrap metals than they once cost to buy in the days when copper and magnetic steel cost a fraction of present prices. Different core designs (as shown here) versus variation of the stack height with identical lamination design produces transformers with varying requirement quantity ratio of iron versus copper, so under the force of their final customers transformer producers vary the design as to whether steel prices rise while copper prices drop or vice versa.

But this approach leaves out of consideration that also the operating behaviour underlies substantial variances due to different core designs or stack heights, respectively. The short circuit voltage can be influenced within an extremely wide range. Heat losses are another important aspect. As a tendency, a transformer with a lot of iron and little copper will have high iron (no-load) losses and low copper (load) losses and vice versa. On the other hand, skimping on both will always drive both types of losses up. A class H transformer (the highest temperature class) may be the smallest of its ratings but is not the best, rather the hottest transformer of its kind and thereby technically the worst.