Enter the Engine Temperatures (hot/cold reservoir), Heat Input, and Work Output into the Carnot Efficiency Calculator to get the Carnot Efficiency, Actual Efficiency, Waste Heat, and COP for heat engines and refrigerators.
Conductor Temperature
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Temperature Rise
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Power Dissipated
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Insulation Max Temperature
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Safety Margin
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Wire temperature rise is calculated using the formula: ΔT = I²R × Rth, where I is current, R is resistance, and Rth is thermal resistance. The total conductor temperature is ambient temperature plus the temperature rise.
The main factors are current flow (squared effect), wire resistance, thermal resistance to ambient, ambient temperature, wire material properties, and installation conditions like bundling or conduit.
Thermal resistance depends on wire size, insulation type, installation method, and ambient conditions. It's typically provided in manufacturer data sheets or can be estimated based on standard values for different wire types and installations.
Common limits are: PVC insulation (70°C), XLPE/EPR (90°C), PTFE (200°C), and Silicone (180°C). Always check manufacturer specifications and local electrical codes for specific requirements.
Power dissipation follows Ohm's law: P = I²R. Since temperature rise is proportional to power dissipated, doubling the current quadruples the temperature rise, making current the most critical factor.
Higher ambient temperatures reduce the allowable current because the wire starts from a higher baseline temperature. Derating factors are applied in hot environments to maintain safe operating temperatures.
A safety margin of 10-20°C below the maximum rated temperature is recommended to account for variations in ambient conditions, load fluctuations, and aging effects on insulation.