Abstract: A stator of a large generator includes three potential, or "P" bars, disposed in slots atop the armature conductors in three of the stator slots. The "P" bars are part of a self-excitation system for producing DC excitation power for the rotating field of the generator. At least the stator slots containing the "P" bars include a pair of dovetail slots spaced radially closer to the air gap than the dovetail slots in the remaining stator slots used for securing armature conductor bars in stator slots. The inner end of a beam is fitted into the dovetail slot over the "P" bar. A yoke is secured over the outer end of the beam. The yoke is secured to studs in space block extensions positioned adjacent the stator slot containing the "P" bar. A ripple spring between the beam and the "P" bar applies a radial force to securely retain the "P" bar and the armature conductor bars in the slot.