Device for assembling capacitors for an electronic converter comprising a plurality of arms provided with transistors, said assembly device comprising a busbar of positive polarity comprising a plurality of power supply taps, each power supply tap being adapted to be connected to a positive electrode of each arm of said electronic converter, and a busbar of negative polarity comprising a plurality of power supply taps, each power supply tap being adapted to be connected to a negative electrode of each arm of said electronic converter, the busbar of positive polarity and the busbar of negative polarity being superposed one on top of the other without electrical contact, characterized in that the busbar of positive polarity also comprises: at least one first positioning orifice adapted to receive a positive pin of a capacitor and adapted to produce an electrical link with said positive pin; and at least one first clearance orifice adapted to allow a negative pin of a capacitor to pass through said busbar of positive polarity without electrical contact; the busbar of negative polarity also comprises: a second clearance orifice adapted to allow a positive pin of a capacitor to pass through said busbar of negative polarity without electrical contact; at least one second positioning orifice adapted to receive a negative pin of a capacitor and adapted to produce an electrical link with said negative pin; and in that the device further comprises an insulating and indexing support piece arranged between said busbar of positive polarity and said busbar of negative polarity, said support piece comprising: at least one first indexing piece for indexing said support piece with the busbar of negative polarity; and at least one clearance orifice adapted to allow a negative pin of a capacitor to pass through said support piece without electrical contact. at least one first positioning orifice adapted to receive a positive pin of a capacitor and adapted to produce an electrical link with said positive pin; and at least one first clearance orifice adapted to allow a negative pin of a capacitor to pass through said busbar of positive polarity without electrical contact; the busbar of negative polarity also comprises: a second clearance orifice adapted to allow a positive pin of a capacitor to pass through said busbar of negative polarity without electrical contact; at least one second positioning orifice adapted to receive a negative pin of a capacitor and adapted to produce an electrical link with said negative pin; and in that the device further comprises an insulating and indexing support piece arranged between said busbar of positive polarity and said busbar of negative polarity, said support piece comprising: at least one first indexing piece for indexing said support piece with the busbar of negative polarity; and at least one clearance orifice adapted to allow a negative pin of a capacitor to pass through said support piece without electrical contact. a second clearance orifice adapted to allow a positive pin of a capacitor to pass through said busbar of negative polarity without electrical contact; at least one second positioning orifice adapted to receive a negative pin of a capacitor and adapted to produce an electrical link with said negative pin; and in that the device further comprises an insulating and indexing support piece arranged between said busbar of positive polarity and said busbar of negative polarity, said support piece comprising: at least one first indexing piece for indexing said support piece with the busbar of negative polarity; and at least one clearance orifice adapted to allow a negative pin of a capacitor to pass through said support piece without electrical contact. at least one first indexing piece for indexing said support piece with the busbar of negative polarity; and at least one clearance orifice adapted to allow a negative pin of a capacitor to pass through said support piece without electrical contact.