/// Highest Copper Filling Factors
The efficiency and power density of electric motors is significantly determined by the filling factor of copper and hence directly related to the copper winding technology. The winding technology represents the most difficult and thus the most expensive manufacturing step. SciMo developed a unique winding technology using distributed wiring that enables copper filling factors of up to 80%. The electrical motors based on this technology show significant improvements in efficiency and power density. Depending on the particular application, the increase in winding costs can be already compensated by the lower material costs for magnets and electric plates. The winding technology developed by SciMo does not use densified copper wires leading to only a slight increase in frequency-dependent losses due to current displacement and eddy current losses (8%, at 1 kHz fundamental wave).
SciMo is currently working on the full automation of the winding technology to reduce the costs further. This will lead in the near future as well for low specified motors to a cost advantage compared to conventional electric motors.
/// Innovative Cooling Concepts
The permanent power density and thus the material costs are significantly determined by the heat dissipation capacity of the electric motor. A continuous power density of 5 kW/kg is achievable using a water jacket cooling.
We use as well the concept of direct oil cooling for the winding heads. This is an appealing solution when the oil is furthermore used for the lubrication of the gearbox. Test measurements with the oil cooling of the winding head showed a quadrupled power dissipation for the same copper temperature. In most applications the disadvantages of oil as cooling liquid like a lower heat capacity and heat conductivity compared to water/glycol are a major concern. Since the non-conductive oil can however flow directly around the windings a significant improved heat dissipation within the machine is still achieved. Taking into account the need for re-cooling of the oil on the overall system level the water cooling is the preferred solution compared to oil cooling for most applications.
The newly developed integrated cooling concept by SciMo optimizes the heat dissipation capacity and is currently used in the electric motor. The cooling medium is water/glycol. The integrated cooling concept of SciMo uses fully insulated cooling pipes routed in the copper slots that enable extreme high continuous power outputs of the electric motor. The lower copper temperature compensates the increased losses caused by the reduced copper cross-section resulting in increased cycle efficiencies for many applications with medium and high load profiles.