The Problem

Variable frequency drive (VFD) systems create damaging motor bearing currents. If these currents aren’t filtered or “choked” – bearing fluting, frosting, breakdown of lubrication, electrical discharge machining (EDM), and motor bearing failure will result. CoolBLUE® with NaLA® absorbs this damaging current before it gets to the motor.

What is a common mode choke?

A common mode choke is an inductor that is used to prevent unwanted high frequency electric signals, and energy, from being transmitted along undesired paths or into inappropriate parts of an electric circuit or system.

CoolBLUE® cores act as a common mode choke by absorbing the high frequency noise, so you can maximize equipment reliability, reduce maintenance costs, and avoid unscheduled downtime.

What is a differential mode line absorber?

NaLA® differential mode line absorbers further reduce the current and slow the frequency down to even lower levels for the highest reliability of your system!

CoolBLUE vs the old solutions

CoolBLUE Solution

Inductive Absorbers / Common Mode Choke

CoolBLUE Inductive Absorbers absorb the noise on the power cables generated from the VFD before it gets to the motor. The CoolBLUE cores act as a common mode choke (CMC) in this given configuration, and dissipates into thermal. No motor modifications, no shaft preparation, very easy installation. Can be added to systems with very minimal downtime.

No costly installations or downtime like traditional grounding ring solutions. No insulated bearings or hybrid bearings.

Lasts the lifetime of system

  1. Installation can be done in a matter of minutes, on site.
  2. Shaft contaminants are not an issue since the currents are absorbed well before the motor.
  3. No extra parts because of motor keyways or wash-down applications. Cores are installed between motor drive and motor, even in harsh conditions.
  4. Last a lifetime of the system. Since it is not mechanical, they only need to be installed once.
  5. Less than a dozen choices cover all motor sizes.
  6. No hybrid or ceramic coated bearings needed, no matter the size.
  7. One choke per system, not per motor.
  8. Common mode chokes are designed to absorb common mode currents BEFORE they get to the motor.
Solution – CoolBLUE Inductive Absorbers!

The Old Solution

Shaft Grounding Rings
  1. Installation is not an exact science. In order for the grounding ring to work sufficiently, it must be properly aligned with fibers touching all sides, at all times.
  2. Installation cost is significant to the end user.
  3. Shaft must be completely free of contaminants, and in some cases a coating must be applied to the shaft, which adds cost.
  4. Cannot be installed over keyways. Extra parts must be installed to avoid keyways.
  5. Cannot easily be installed in motors in wash down applications.
  6. They have to be replaced every time anything is done inside the motor, i.e. new bearings are installed.
  7. Literally hundreds of products to fit hundreds of different motor shafts or motor sizes.
  8. On systems above 75HP, a hybrid or coated bearing/raceway is needed on non-load side of motor.
  9. Shaft must remain clean from contaminants. Any material, oil/grease/corrosion/other, will cause the fibers to loose contact, and lose their ability to properly shunt the currents to ground.
  10. One product per motor. For example, a simple wall of fans driven by one drive, requires all motors to have grounding ring installed.
  11. Grounding rings do not get rid of the destructive currents. They provide a path to motor casing. If the motor casing is not properly grounded, that stray current can and will go into other parts of the system…back to VFD, to the load, etc.
  12. Margins on grounding rings are very high, and very profitable for the reseller.
They will not tell you about better solutions.