October 17, 2022
Cardan Shaft? Spacer Shaft? What Kind Is It?
By Mac MacCormack
Recently, I provided training for a location that had vertical mounted electric motors driving pumps that were one or more floors below them.
In this case, these pumps were driven with Cardan Shafts, however they did not have the typical 5-to-15-degree angles (between the motor & pump shafts and the drive shaft) recommended for lubrication and load distribution on the needle bearings of the U-joints.
The small openings in the floor, for the drive shafts to pass through, are not ideal for using Cardan Fixtures.
Could the alignments be done with a spacer shaft function? Maybe, but it is a C-face mounted electric motor.
Could this alignment be treated as a standard vertical alignment?
What do YOU think?
You’d probably be safe doing so but I’d have vibes tech present at startup… I used to align vertical cooling tower pumps with rabbit fit to either motor or turbine gearbox, most important thing here was setting vertical pump impeller clearance (thank God for inside snap guages) question I have for you is purposely setting the driver low(steam turbine) or high (cryogenic power recovery turbines) what do you consider the best method?