A positioning device may be used to peripherally position copper rods about a center axis that defines an axial direction. Each of the copper rods may be generally U-shaped and may have a first leg portion and a second leg portion. The positioning device may include a positioning body, a rotary body, locking means, and a rotary drive. Grooves of an outer peripheral surface of the positioning body may receive the first leg portions of the copper rods, which can be locked in place by the locking means. The rotary body may be rotatable about the positioning body and may include guide channels that receive the second leg portions of the copper rods. The rotary drive can cause the rotary body and the positioning body to rotate relative to one another, to pivot the second leg portions inwardly into the grooves of the positioning body.