Explanation of results: Powers and losses


It is necessary to give more details about the computation of different powers and losses.

Active power and Joule losses: Why?

In the steady state AC application, Flux can compute:

  • the apparent power S = ModC(PowV)
  • the reactive power Q = Imag(PowV)
  • the active power P = Real(PowV)
  • the Joule losses:
    • region of coil conductor type:
    • region of solid conductor type:

Question: the active power and Joule losses are they identical?

Answer: yes and no, according to the modeled case. (see following block)

Formula details

Here is a reminder of formulas in steady state AC application:


The first part is mandatory a real because J* can't be complex.

But the second part can have a real part and an imaginary part when the case is modeled with a complex permeability:

  • if ì isn't complex → active power = Joule losses
  • si ì is complex → active power ≠ Joule losses

Joule losses (coil conductor)

Two possibilities to compute Joule losses of a coil conductor:

  • on a region:

    (in steady state AC Magnetic)

(in transient magnetic)

with RCCreg = resistance computed in function of the material and of the fill factor* associated to the region of coil conductor coil*.

  • on a component:

    (in steady state AC Magnetic)

(in transient magnetic)

with RCCcomp = RCCreg + RCCadd

where RCCadd corresponding to the resistance defined in the coil conductor

Note: * To compute RCCreg, it must mandatory that the corresponding region have an associated material (defined with a resistivity) AND a fill factor (between 0 and 1) which are optional fields.

If one field is missed, the computation on region of Joule losses is « Invalid » and the computation on component of Joule losses takes into account only the RCCadd