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External mechanical tolerances for electric motors and generators

Publication date: 
August 2014
Author(s): 
Tom Bishop, P.E., EASA Senior Technical Support Specialist
Type of media: 
Article

Service centers routinely check the shaft extension runout of motors and generators. When there are issues associated with them, or when applicable, the coplanarity of the mounting feet and the amount of end foat of horizontal sleeve bearing motors and generators are checked. A common point about all three of these dimen-sions is that they are checked with the machine assembled; that is, no disas-sembly is required. There are many other mechanical tolerances associated with motors and generators, such as bearing fits. However, the focus of this article will be the three tolerances just mentioned. Rather than referring to both electric motors and generators, for brevity the term “machine” will be used.

Topic(s): 
AC motors
Alternators/generators
Base/soleplate/foundation
Bearings
Frame
Repair procedures and tips
Shafts