Direct Current Permanent Magnet (DCPM) motors generate waste heat just like any other rotating electrical machine. There are different methods for cooling electric motors, and in this example we will use the Modelica Standard Library to study one such method.
The cooling circuit consists of the thermal capacitance of the armature, the thermal conductance between armature and core, the thermal capacitance of the core, and the thermal conductance between the core and the cooling pipe.
The diagram image shows the cooling unit in blue at the bottom. It is a coolant flow circuit that consists of an inlet, a volume flow of cooling liquid, and a pipe connected to the core and the outlet.
The temperature development in the cooling circuit. The temperature drops as we move further along the cooling circuit. The temperature in the cooling pipe is the same as the outlet temperature.
It might also be interesting to see how the temperature development changes with different cooling circuit properties. The heat transfer through the system is, among other things, affected by the capacitances of the armature and core, as well as the conductance between the armature and core and between the core and the cooling pipe.