Apparatus for aligning ends of wire conductors extending from coil members inserted in slots of a core of a dynamo electric machine to join a plurality of ends (EP1, EP2, EP3, EP4, EP5) of at least two wire conductors, in particular by means of a welding operation; wherein said ends (EP1, EP2, EP3, EP4, EP5) to be joined are intended to be aligned along radiuses (R1, R2) of said core, and wherein a spacing (S1, S2) exists between two adjacent radiuses (R1,R2) of said core; said apparatus comprising at least one first alignment unit having: - a first member configured for being positioned in a first spacing existing on one side of a first radius of the core; - a first abutment portion (23', 33') configured for being positioned at a first position situated radially between a first group of ends to be joined and a second group of ends to be joined, said first and second group of ends being intended to be aligned along said first radius; - a second member configured for being positioned in a second spacing existing on the opposite side of said first radius; - a second abutment portion (33', 23') configured for being positioned at a second position situated radially between said first group of ends to be joined and said second group of ends to be joined; - a first pusher situated at a radially outer position relative to said core and configured for pushing said first group of ends to be joined against said first abutment portion (23', 33'); - a second pusher situated at a radially inner position relative to said core and configured for pushing said second group of ends to be joined against said second abutment portion (33', 23'); - first means (302, 308) configured for relatively moving said first member, said second member, said first abutment portion (23', 33') and said second abutment portion (33', 23')in an axial direction (Z, Z') of said core; - second means configured for relatively moving said first radial pusher and said second radial pusher in the radial direction (R, R') of said core; and - third means configured for moving said first member and said second member one towards the other in the circumferential direction (CS, CS')of said core. - a first member configured for being positioned in a first spacing existing on one side of a first radius of the core; - a first abutment portion (23', 33') configured for being positioned at a first position situated radially between a first group of ends to be joined and a second group of ends to be joined, said first and second group of ends being intended to be aligned along said first radius; - a second member configured for being positioned in a second spacing existing on the opposite side of said first radius; - a second abutment portion (33', 23') configured for being positioned at a second position situated radially between said first group of ends to be joined and said second group of ends to be joined; - a first pusher situated at a radially outer position relative to said core and configured for pushing said first group of ends to be joined against said first abutment portion (23', 33'); - a second pusher situated at a radially inner position relative to said core and configured for pushing said second group of ends to be joined against said second abutment portion (33', 23'); - first means (302, 308) configured for relatively moving said first member, said second member, said first abutment portion (23', 33') and said second abutment portion (33', 23')in an axial direction (Z, Z') of said core; - second means configured for relatively moving said first radial pusher and said second radial pusher in the radial direction (R, R') of said core; and - third means configured for moving said first member and said second member one towards the other in the circumferential direction (CS, CS')of said core.