Question

Transformers are very efficient devices with efficiencies of typical distribution and power transformers approaching 96 to as high as 99 percent. List three causes that can reduce transformer efficiencies

Answer 1

1. Load losses result from resistance in the copper or aluminum windings. Load losses (also called winding losses) vary with the square of the electrical current (or load) flowing through the windings.

2.No-load losses result from resistance in the transformer's laminated steel core. These losses (also called core losses) occur whenever a transformer is energized and remain essentially constant regardless of how much electric power is flowing through it.To reduce core losses, high-efficiency transformers are designed with a better grade of core steel and with thinner core laminations than standard-efficiency models.

3. Stray losses: Not all the magnetic field produced by the primary is intercepted by the secondary. A portion of the leakage flux may induce eddy currents within nearby conductive object such as the transformers support structure, and be converted to heat. The familiar hum or buzzing noise heard near transformers is a result of stray fields causing components of the tank to vibrate, and is also from magnetostriction vibration of the core.

4.Mechanical losses: The alternating magnetic field causes fluctuating electromagnetic forces between the coils of wire, the core and any nearby metalwork, causing vibrations and noise which consume power.

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