Electrical Bearing Protection Q&A Part 11

Part 11 in a series of questions and answers from our Q&A webinars.

Q1:  What are the high and low temperature ratings for AEGIS® Rings?

A1:  We know for a fact that they work from -112 up to 410°F (-80 to 210°C).   Those are the lab-tested values.  But the rings didn't fail over that whole range, so we don't know what the true limits are.  We actually got a question recently from an engineer about the Mars Rover.  Now, the average surface temperature of Mars is -180°F (-63°C).  There's certainly nowhere on Earth that's too cold for AEGIS rings to work.

At the hot end, we know of them being used in some pretty hot ovens.  If you have an extreme application, just give us a call and talk to our engineers.

Q2:  What is the maximum speed capability of the AEGIS ring, and can the motor reverse direction without damaging the fibers?

A2:  It depends on the shaft diameter.  We have small shafts on high-speed routers at 32,000 rpm.  But what counts is the surface speed; for a given rpm, the bigger the shaft, the bigger the surface speed.  1800 & 3600 rpm are typical; you usually don't have large shafts at tens of thousands of rpm.

If you're ever concerned that AEGIS won't work, call us.

As for reversal:  We've been testing this for years, and they're still going.  I think we're up to 40 million reversals, with almost no wear.  The fibers are slightly overly long, and they do wear slowly, but only to the level of the shaft at most.


This cooling tower is not too moist for internally mounted AEGIS rings.  Photo © Reginald van de Velde.

Q3:  How does a high-moisture environment affect the ring's performance?

A3:  If the humidity's not condensing, there's no effect at all.  The ring does not like to be immersed in water, though (or any liquid).  So if the ring is likely to get wet, it should be installed internally, like in these Marathon and US Motors cooling tower motors.

For most applications, the bigger risk will actually be the shaft oxidizing due to humidity.  So in a very humid environment, especially if the ring is mounted externally, you should probably use our colloidal silver shaft coating.

Q4:  If you've got a motor with under 100 hp, that is not controlled by a drive, is there any need for an AEGIS ring?

A4:  No, small motors run across the line do not need shaft grounding.  But, if there's ever any chance that the system might be upgraded to use a drive, then it might be wise to include AEGIS shaft grounding just so you will be all ready for the change when it happens.

AEGIS Rings come with a 2-year extended warranty against bearing fluting damage. No other form of protection against VFD-caused bearing damage offers a warranty like this.

To learn more about AEGIS shaft grounding and best practices for electrical bearing protection, sign up for a training. We offer monthly live training webinars, and - pandemic restrictions permitting - we can also visit your facility to review your exact application.