The history of the transformer. Part 4.

Transformers are used in power transmission systems

Many specialists have been looking for ways to transfer electricity at a higher voltage than what was required in consuming devices.

In 1884, Westinghouse hired a young engineer, William Stanley , who had the idea of ​​using a transformer to solve electricity. Learning about the work of Golars and Gibbs, he advised Westinghouse to acquire patents for the transformer.

Stanley was convinced of the advantages of parallel connection schemes, and by the beginning of the summer of 1885 he had already created several transformers with cores of closed form.

Soon, in connection with the deteriorating state of health, Stanley was forced to leave with his laboratory from industrial smoky Pittsburgh. With the approval of Westinghouse, he moved to Great Barrington, Pa. Massachusetts, where he continued to work on transformers.

In the meantime, Westinghouse, not yet fully convinced of the efficiency of the parallel connection, experimented with various combinations of secondary generators Golar and Gibbs, along with another pioneer in electrical engineering, Oliver B. Schellenberger .

Stanley Transformers - Westinghouse

By December 1885, Stanley's success had finally convinced Westinghouse and he, along with Schellenberg and another brilliant engineer Albert Schmidm, had begun to improve Stanley's transformer so that it (unlike the Hungarian toroidal device) became simple and cheap in production .

At first, the core was made of thin iron plates in the form of the letter H. Windings from insulated copper wire were wound onto the horizontal part of the core, the free ends of which were closed by additional layers of iron strips.

Stanley suggested making iron plates in the shape of the letter W, so that the central rod could easily be inserted into a pre-wound coil. Sh-shaped plates were stacked in alternating opposite directions, and straight iron strips were laid on the ends of the plates to close the magnetic circuit. This design of the transformer is used today.

The cores of the first Stanley-Westinghouse transformers consisted of thin plates of sheet steel and were characterized by significant losses due to hysteresis - the so-called memory effect in magnetic materials, which reduces the efficiency of the transformer. These losses gradually began to decline due to careful selection of grades of steel.

The way to modern transformers

In the early 1900s, the English explorer-metallurgist Robert Hedfield conducted a series of experiments to determine the effect of additives on the properties of iron. Only a few years later he managed to supply the customers with the first ton of transformer steel with silicon additives.

The next major leap in core technology was made in the early 30s of the XX century, when the American metallurgist Norman P. Gross established that, in the combined effect of rolling and heating, outstanding magnetic properties appear in the siliceous steel in the direction of rolling: magnetic saturation increased by 50 %, Hysteresis losses were reduced 4 times, and magnetic permeability increased 5 times.

However, the improvement of transformers and power supply circuits for radio electronic devices based on their application continues to this day.

Author of the article: Alexander Semenov. Based on Scientific American