The efficiency of a transformer can be measured using various metrics, depending on the specific context and application. In the context of power transformers used in electrical systems, the most common efficiency measurements are as follows:
Power Efficiency (or Energy Efficiency): This is one of the most important efficiency metrics for power transformers. It represents the ratio of the output power (Pout) to the input power (Pin), expressed as a percentage:
Power Efficiency (%) = (Pout / Pin) * 100
The output power is the power delivered to the load, and the input power is the power drawn from the power source.
Copper Loss Efficiency: Power transformers have winding coils made of copper, which exhibit resistance. The current flowing through the windings causes copper losses, which can be significant. Copper loss efficiency measures how well the transformer handles these losses. It is the ratio of output power to the sum of input power and copper losses:
Copper Loss Efficiency (%) = (Pout / (Pin + Copper Losses)) * 100
Iron Loss Efficiency (or Core Loss Efficiency): The core of a transformer is usually made of laminated steel sheets, which experience magnetic hysteresis and eddy current losses. Iron loss efficiency evaluates the transformer's ability to mitigate these losses. It is the ratio of output power to the sum of input power and iron losses:
Iron Loss Efficiency (%) = (Pout / (Pin + Iron Losses)) * 100
Total Loss Efficiency (or Overall Efficiency): This is a comprehensive metric that takes into account both copper losses and iron losses, along with any other auxiliary losses. It is the ratio of output power to the sum of input power and all losses:
Total Loss Efficiency (%) = (Pout / (Pin + Copper Losses + Iron Losses + Other Losses)) * 100
Efficiency is a crucial factor in power transformers since higher efficiency results in less wasted energy and lower operating costs. Moreover, it contributes to a greener and more sustainable electrical grid.
For other types of transformers used in signal processing, data analysis, or natural language processing (like the transformer model itself), efficiency metrics may differ based on their specific tasks and objectives. Some common measures in those contexts could be processing speed, memory utilization, or throughput, depending on the application.