Don't Let Motor Repair Costs Wipe Out Energy Savings
|A key goal of modern HVAC systems is to eliminate energy wasted on overheating or overcooling areas of a building. Matching heating/cooling capacity to load can yield tremendous energy efficiency gains and dramatically reduce building energy costs.
And a key tool in this quest is the variable frequency drive, or VFD. By controlling the amount of power to motors, VFDs can precisely match HVAC capacity to discrete areas within a building, eliminating the energy costs associated with conditioning and moving the air, as well as the costs of overconditioning the air. Because the energy required to run fan or pump motors correlates to their flow rate cubed, reducing the speed of these motors by half reduces the horsepower needed to run them by a factor of 8. And restricting the flow from a motor working at full speed through the use of dampers or other throttling mechanisms is simply a waste of energy and money.
But while VFDs provide significant energy savings in HVAC applications, they can also damage motors. VFDs create voltage on the shafts of the motors they control. This voltage can discharge to ground by arcing through the motor bearings, causing pitting in the bearings' ultra-smooth bearing race.
This damage accumulates over time, and leads to premature bearing failure. In the end the user must repair or replace the motor, possibly cancelling out the energy cost savings from using a VFD. And the user will face the cost of unplanned downtime to boot!
To protect VFD-driven motors from electrical bearing damage, effective long-term bearing protection is needed. As proven in millions of installations worldwide, AEGIS® Shaft Grounding Rings channel harmful voltage discharges away from bearings and safely to ground, protecting motor bearings for their full L-10 life.
AEGIS® protection is available in solid rings for installation before motors are put into service and in split rings for fast, easy field installation on coupled in-service motors. AEGIS® uKITs include an AEGIS® Ring (solid or split) and a set of mounting brackets that speed and simplify installation on motors with shaft shoulders, slingers, or other end bell protrusions.
But by far the easiest way to protect motors from VFD-induced bearing damage is to buy them new with AEGIS® Rings factory-installed. A large number of motor manufacturers now offer motors with AEGIS® Rings pre-installed externally or inside the motor, either off-the-shelf or through their modification shops.
So don't let motor repair and replacement costs eat up the energy cost savings that VFDs provide. Protect your motors from VFD bearing damage with AEGIS® Bearing Protection Rings.
To download a copy of our White Paper on protecting HVAC motors from electrical bearing damage, click here.
For more information on AEGIS® Rings and uKITs, click here.
The AEGIS® website has a section devoted to the manufacturers who offer AEGIS® Rings factory installed in their motors: AEGIS® OEM Pages.
To download our Bearing Protection Handbook of best practices for diagnosing and preventing VFD-caused bearing damage, click here.