There are analytical and numerical analyses that could be used to study heat flow generated and mechanical friction relation in alternators. In analytical method the losses that occur in the machines, efficiency and temperature can be calculated. Here heat rate and flow rate are obtained by calculating conduction, convection, radiation resistances and machine losses such as core loss, copper loss and mechanical losses (including mechanical friction). This analysis provides efficient and fast result but it cannot provide heat flow path and point out where the maximum heat is produced in the machines. On the other hand, numerical analyses consume large time for simplification but give heat flow rate very accurately for any complex regions. Generally thermal analysis of the machine helps to find total temperature produced in the machine and heat flow direction in the machine. In coupled magnetic field and thermal analysis, the result of electromagnetic field analysis (i.e., losses) forms the input for thermal analysis.

For example, in analytical method, the conduction thermal resistance can be calculated by Rconduction = L/KA, where L is the path length in meters, A the path area in square meters and K is the thermal conductivity of the material in °C. The convection thermal resistance of the surface is Rconvection = 1/Ah, where A is the surface area in square meters, h is heat transfer coefficient in watt per square meter per °C. The radiation thermal heat resistance for a given surface is given by Rradiation = 1/(A*hc), where hc is the convection heat transfer coefficient in watt per square meter °C. The total heat flow rate in the given surface is Delta_T/R, where Delta_T is the surface temperature rise and R is the flow resistance. Copper losses also has to be considered. Total stray losses are given by Pstray = Load fraction^0.8 * (Machine rating*(50/f))^0.59 * (f/50)^1.5.

The above mentioned equations can be better studied in the follow links:

Article Electromagnetic & thermal analysis of synchronous generator ...

https://ieeexplore.ieee.org/abstract/document/4796880

https://ieeexplore.ieee.org/abstract/document/4153729

I hope this information was helpful.

Tarsis

Are you talking about the alternator in a car? If so, the vast majority of heat generated comes from I²R losses following the constantly shifting magnetic field. The bearing and air swirling contributions are negligible by comparison. Just rest your hand on the casing for a moment to verify this.

Генератор переменного тока - электромагнитная индукции - если сопротивление всей цепи равно R, то по ней будет протекать индукционный ток, равный Iинд = 📷инд/R. За время Δt на сопротивлении R выделится джоулево тепло 📷

no I ask this question for an alternator of a gas turbine power plant