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Re: The Moreton Effect

From: Steve Schultheis
Remote Name: 161.16.0.51

Comments

The Morton effect behaviour is basically the same as that of a light rub that induces heat into the journal in a localized area, causing the rotor to bow. So one good clue to the Morton effect is that you watch as a straight rotor begins to bow, but you find no evidence of a rub. Typically the Morton effect occurs on overhung impeller machines, with small diameter high speed very flexible rotors, and it usually occurs on the impeller end bearing which is carrying the bulk of the load. Varying oil temp usually does not have much effect, and the two times I have experienced it we tried both cooler and warmer oil to no effect. Changing the bearing geometry should work in solving the problem, but the most common fix is to sleeve the journal, so that the journal is in effect insulated from any localized heating due to fluid shear in the bearing. Probably the best way to identify the Morton effect is to sleeve the journal, and if that fixes it, then that is probably what it was....

Last changed: October 16, 2007