Winding Heating

The power needs to be supplied by the electric motor at the shaft end is more diminished than the power the motor can absorb from the power line, so the motor efficiency will always be less than 100%.

In closed motors, this dissipation is assisted by the fan installed on the motor shaft itself. A practical dissipation may be modified, depending on the strength of the ventilation system of the total dissipation area of ​​the housing, of the temperature difference between the outer surface of the housing and the ambient air.      2100-5M-15 Gates

The main difference between the two powers is the heat losses, which automatically heat the winding and dissolve into the external environment of the engine, with the main function of preventing the increase in temperature from being considered excessive. The same fact can happen in all other types of engines.

In the case of a car engine, the heat generated by the internal losses will be taken from the block through the water circulation system with the radiator or by the fan in the case of air cooled engines. The heat generated by the losses inside an enclosed motor is wasted into the ambient air through the outer surface of the housing.

The Sizing of Magnets

Induction in the air gap is strictly proportional to the remaining induction and the surface of the magnet. The first defined dimension is the height of the magnet, which will then be the entire length of the rotor, with a clearance of 2.05 mm at the end. The second dimension of the magnet will be the thickness that should be determined so that the maximum current that can be presented by the converter will not demagnetize the magnets in the rotor.

Since the remaining induction is a property of the magnet, attention is focused on the size of the magnet. In the buried magnets, special care must be taken to prevent the flow from flowing and proceed from the north pole to the south pole without passing through the engine air gap. An axis in non-ferromagnetic material will be fundamental.

An alternative to be checked is the application of a ferromagnetic axis enveloped by a layer of non-ferromagnetic material, as this option reduces the cost of the shaft, however it increases the cost of manufacture, as it increases the number of assembly elements. In order to minimize the dispersed flow, the magnets lie against the non-ferromagnetic axis, so there is no path in the center of the rotor for the flow to disperse.