Problems with pump bearings
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Can the N326 and NU326 bearings be used interchangeably in horizontal double-suction pumps?
Series N bearings are those with a double flange on the inner ring, while NU bearings have a double flange on the outer ring. By common sense, when using N or NU series bearings, 7 series bearings that are paired with them are definitely used to axially position the rotor. The NU series only provides radial support and does not bear axial forces; modifications must be made in accordance with the manufacturer’s instructions. Personally, it can be used temporarily as a substitute when suitable parts are unavailable, but it should not be used for an extended period of time.
One more question: First, make sure to check whether the shaft that was originally fitted with N-series bearings can still be removed if NU-series bearings are installed on it. Do not overlook the fact that if the outer diameter of the inner ring is smaller than the diameter of the shaft shoulder, it will be difficult to remove it.