November 6, 2014
“Electrical Pipe Strain?”
By Tom Shelton
Precision shaft alignment of rotating equipment is an essential part of any solid preventative maintenance program. To accommodate aligning any type of machinery you must be able to move one of the elements of the machine to achieve a precision shaft alignment. There are many limiting influences that could cause you to not be able to move some part of a machine. Some common examples are bolt bound/base bound condition, pipe strain, structural interference, etc…
Recently I was with the maintenance crew of a fresh water supply system in a major city. These guys were familiar with shaft alignment and the importance of aligning their pumps and motors to keep the people of the city happy and supplied with clean water. The crew had been using Fixturlaser Laser Shaft Alignment equipment for many years and had recently upgraded their systems by purchasing a NXA Pro system. As is the case with most of our customers, upon purchasing the NXA the customer opted to have a trainer from VibrAlign come on-site and give them some updated training in shaft alignment best practices. During the hands on portion of the training we went to one of the many pump stations that the maintenance crew is responsible for.
Upon initial inspection of the motor/pump sets to be aligned, we discovered a major road block. Two of the motor/pump sets could not be aligned, without some structural work, as the electric motors could not be adjusted vertically or horizontally due to the rigid conduit and the junction box severely restricting movement. In other words the motor had severe “electrical pipe strain”. Also, the pumps could not be moved as the piping was rigid and very close.
Two other electric motors took a little encouragement from a come-a-long to give some room from the conduit/junction boxes for the motor to be moved.
Be mindful of ALL of the influences that could affect your shaft alignment or limit the ability to align a machine.
Take time to look at possible influences that could limit movement or cause distortion in the machine components. Sometimes machines are not align-able without major work. Remember though, once you have fixed it, you won’t have to do it again and with a proper alignment the frequency of failure of that machine declines substantially.
The conduit is rigid and directly attached to the motor with no freedom of movement.
The junction box is against the breaker panel. This one we were able to pull the breaker panel far enough away to align the equipment. It still needs to be modified.
Plenty of clearance here.