A submersible pump electrical motor has a bearing hub between adjacent rotor sections. The bearing hub has a hub outward facing sidewall and a hub inward facing hub sidewall through which the shaft extends. A collar having a collar inward facing sidewall is rigidly mounted to the hub outward facing sidewall. The collar has a collar outward facing sidewall spaced from stator sidewall by an annular clearance. A slit in the collar extends from the collar inward facing sidewall to the collar outward facing sidewall. An anti-rotation spring has a supporting portion inwardly biased against the hub outward facing sidewall and a locking portion protruding outward through the slit into engagement with the groove to prevent rotation of the hub and the collar.