Calculate coil temperature from ambient temperature, power, surface area, and heat transfer coefficient, or solve voltage, current, resistance, and power.

Steady-state uniform surface, convection only. Radiation, conduction and internal hot spots are omitted.

Illustrative coefficient

Examples only. Use a coefficient measured or modeled for your geometry, fluid and flow.

Coil Temperature Formula

The following formula is used to calculate the coil temperature for a given set of parameters.

Tc = Tโ‚ + (P / (A ร— h))

Variables:

  • T_c is the coil temperature
  • T_a is the ambient temperature
  • P is the power dissipated
  • A is the surface area
  • h is the convective heat transfer coefficient for the actual geometry, fluid and flow conditions

This steady-state convection model estimates a uniform coil surface temperature: T_c = T_a + P/(A h). Use P in watts, A in square meters and h in W/(mยฒยทK), with both temperatures in ยฐC or K. It omits radiation, conduction and internal hot spots; it does not determine winding hot-spot temperature or insulation safety. The illustrative coefficient values are examples, not validated fluid presets.

What is Coil Temperature?

Coil temperature refers to the temperature of a coil, which is a wound conductor used in various electrical and electronic applications. The temperature of the coil is influenced by factors such as the ambient temperature, the power dissipated by the coil, the surface area of the coil, and the heat transfer coefficient. Maintaining an optimal coil temperature is crucial for the efficient operation and longevity of electrical devices, as excessive temperatures can lead to insulation breakdown, reduced efficiency, and potential failure of the coil.

How to Calculate Coil Temperature?

The following steps outline how to calculate the Coil Temperature.

  1. First, determine the ambient temperature (T_a).
  2. Next, determine the power dissipated by the coil (P).
  3. Next, determine the surface area of the coil (A).
  4. Next, determine the heat transfer coefficient (h).
  5. Finally, calculate the Coil Temperature using the formula T_c = T_a + (P / (A * h)).
  6. After inserting the values and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

Ambient Temperature (T_a) = 25ยฐC

Power Dissipated (P) = 100 W

Surface Area (A) = 0.5 mยฒ

Heat Transfer Coefficient (h) = 10 W/(mยฒยทK)

For these illustrative inputs, the temperature rise is 100/(0.5 ร— 10) = 20 K, so the estimated surface temperature is 45ยฐC. The separate electrical modes use Ohmโ€™s law and resistive power relationships for DC or purely resistive RMS quantities; an inductive AC coil requires impedance and power factor.