Inverter unit with improved bus-plate configuration

An inverter unit comprising:

• a plurality of capacitors for smoothing a direct current, each of said capacitors having a capacitor pole surface containing first polarity capacitor poles and second polarity capacitor poles and defining a first pole surface area;
• a plurality of switching elements for inverting said direct current into an alternating current, each of said switching elements having a switching pole surface containing first polarity switching poles and second polarity switching poles and defining a second pole surface area;
• insulating plate means for providing electrical insulation and defining an insulating surface area;
• first bus-plate means for electrically connecting said first polarity capacitor poles and said first polarity switching poles, said first bus-plate means defining a first plate area that is at least the size of the area defined by the total of said first and second surface areas;
• second bus-plate means for connecting said second polarity capacitor poles of said capacitors and said second polarity switching poles, said second bus-plate means defining a second plate area;
• said first and second bus-plate means being disposed with said first plate area and said second plate area substantially adjacent to each other and said insulating plate being disposed therebetween.