The Variable Frequency Drive, or VFD, emerged a number of decades ago — designed to provide precision, control, and substantial energy savings to both industrial, and commercial applications. Most electric motors today are designed to work with variable frequency drives, saving money by optimizing process efficiency and reducing energy costs. However, VFD systems do come with a slight drawback, in that they can create a significant high frequency currents, known as motor bearing currents or shaft currents.
Until recently, the best way to mitigate the damage caused by motor bearing currents was to use expensive (and unreliable) grounding devices and insulated bearings. However, a new, less expensive and a permanent approach has emerged in the form of CoolBLUE inductive absorbers. Designed for VFD or inverter systems, the innovative CoolBLUE absorbers reduce and may eliminate damage that motor bearing currents cause, lowering the chances of motor failure.
How CoolBLUE Inductive Absorbers Work
The unwanted side-effect of motor bearing currents in VFD systems is actually caused by the IGBT’s rapid firing, at the beginning of each pulse, creating a voltage overshoot that generates high frequency common mode current. These currents travel (being induced into the motor rotor) into and through the motor, resulting in unwanted electrical discharge machining of the bearings and stressing the motor wiring insulation to the VFD system. These high frequency damaging currents cause a significant amount of electrical noise, as well as a list of mechanical issues that collectively impact the lifespan and efficiency of the motor, including:
- Lubrication breakdown
- Bearing frosting
- Bearing fluting
- And if not caught, bearing seizure resulting in winding failure
Which are all the side effects of unwanted and uncontrolled electrical discharge machining (EDM).
By absorbing the high frequency electrical signals that occur when using variable frequency drive systems, CoolBLUE Inductive absorbers efficiently dampen asymmetrical high frequency currents, while suppressing the asymmetrical EMI currents radiated by the motor cable and motor. The magnetic cores used in CoolBLUE’s latest technology work to choke the asymmetrical current, without negatively affecting the symmetrical power currents in the motor.
The Unique Benefits of CoolBLUE
The innovative CoolBLUE design uses nanocrystalline absorbers to function – this makes them far more effective than many other soft magnetic materials, due to their improved magnetic properties and higher temperature capabilities. Unlike other common options, such as ferrites which also lose their properties at lower temperatures, CoolBLUE inductive absorbers only use about 20% of the magnetic mass used by other absorber thus reducing the number of cores needed, are unaffected by higher temperatures, and reduce the amount of maintenance required.
CoolBLUE’s unique absorbers help electric motors to function more reliably, and continue producing consistent results while never needing replacement as they do not wear. Because they can manage the destructive high frequency currents that VFD systems generate, CoolBLUE absorbers can maximize output, while minimizing costly maintenance or downtime. When used with your VFD rated electric motors, this absorption technology provides:
1. Cost Savings
The less time you have to spend repairing and replacing electrical motor bearings and motors, the more time and money you can spend on growing your business. CoolBLUE absorbers reduce or eliminate the damage done to expensive systems caused by motor shaft currents, so that machines last longer. The small number of core sizes meet all motor applications, which makes it easy to find the one that works for any business, and CoolBLUE cores last a lifetime, with no maintenance required.
2. Time Saving
Not only does installing CoolBLUE inductive absorbers take a matter of minutes, but you’ll also save on crucial downtime that could occur as a result of ignoring the damaging motor shaft currents that VFD systems can produce. In other words, electric motors spend less time in need of repair, and more time producing profitable results.
3. Better Reliability and Results
CoolBLUE cores reduce over voltage peaks in motor terminals, while suppressing asymmetrical EMI currents at the same time. This combination of effective and on-going protection allows for greater efficiency and productivity from any electric motor. With CoolBLUE technology, damaging high frequency noise is choked, maximizing equipment reliability and minimizing costs.
Do You Need CoolBLUE Inductive Absorbers?
No matter how expensive or reliable you consider your VFD system to be, it’s important to recognize that any variable frequency driven motor is susceptible to damage as a result of asymmetrical frequencies and motor shaft currents. This doesn’t mean that managers should stop using VFD motors, however, as they are undoubtedly more cost-effective, practical, and precise than alternative methods in many circumstances.
Investing in CoolBLUE inductive absorbers can allow individuals to access all of the benefits that come with variable frequency drives, without the unwanted problems of shaft current bearing damage and consequent maintenance costs over time. Used properly, CoolBLUE inductive absorbers are capable of saving companies immeasurable amounts of money in various industries.
Have you used CoolBLUE inductive absorbers before? Let us know in the comments below!