How to Choose a Shaft Grounding Ring - Part 3
So far, we have covered clamp-on and conductive epoxy mounting for external installation and bolt-through and press-fit mounting for installing an AEGIS ring inside a motor. This time, we will cover our universal mounting kits.
When to Choose the AEGIS uKit
The fifth and most popular style of AEGIS ring is the uKIT, which is available in solid and split builds. uKITs include a grounding ring and four different sets of mounting brackets. Those brackets allow you to position the SGR at the working diameter of the shaft. (The working diameter is the U dimension for NEMA frame motors, or D dimension for IEC frame.)
That means that all you need to know to choose a uKIT is the motor's frame size. There's no need to measure the shaft if it's wider than the working diameter where the ring would sit. This makes it much easier to size a uKIT than one of the other mounting styles. AEGIS uKITs are available for NEMA frame sizes from 56 to 449T, and IEC frames 100L to to 355M.
The mounting brackets themselves can be attached with bolts, requiring a drill and tap, or with conductive epoxy (EP2400). A split uKIT with conductive epoxy is arguably the easiest AEGIS ring to install.
There are only a few cases where a uKIT wouldn't work. Close-coupled pump motors (NEMA frames ending JM or JP) may not have room for a uKIT with mounting brackets between the motor and pump. In this case, you would want a clamp-on or bolt-through ring, either at the drive end or the opposite end (between the motor frame and the cooling fan).
And uKITs can't be installed inside the motor, as they are sized for the working diameter of the shaft, not the internal diameter. So in very wet or dirty environments, you would prefer to install a bolt-through SGR inside the motor, rather than a uKIT outside. This can be mitigated somewhat by sliding an O ring up the shaft to guard the fibers, as shown.
AEGIS Shaft Grounding Rings also have a 2-year extended warranty against bearing fluting damage. No other form of shaft grounding offers a warranty like this.
To learn more about AEGIS shaft grounding and best practices for electrical bearing protection - for motors and generators - sign up for a training. We offer monthly live training webinars, and we can also visit your facility to review your exact application.