An affordable strategy that protects Motor Insulation and Lubrication as well as Bearings.

Bearing Damage Stopped at the Source.

Bearing Damage from Variable Speed Drives is a common issue.

AF500 Fan 55kW showing signs of Bearing damage had a 10 Second count of 26533 EMF with SKF Tked1 (That’s an elevated reading).

The first step is too ensure proper grounding. 85% reduction to 3944 counts by:

Earthing Back Plane, Earthing Cable glands, and Cable Screens.

The Second Step is to fit EMF (Electro Magnetic Frequency) Cores for a 99.2% reduction in EMF Counts.

These EMF Cores contain a nano crystalline wound metal that filters High Frequency Current typically >40kHz not affecting normal 50Hz supply.

These EMF Cores show no impedance at lower frequencies, and as the High Frequency Bearing Current passes into the core they are converted to heat. There is a trade off between the amount of impedance and the heat dissipation, which can be selected with different materials.

This type of EMF Core is much more effective than using ferrites  which are compressed powered metal alloy.

The final Result 190 counts in 10 Seconds

That's a 99.2% reduction in Harmful Drive emissions that

attack Motor Insulation, Lubrication and Bearings.

This is a permanent fix at the source that doesn’t degrade or fail.

Note: Insulated Bearings and Grounding Brushes don’t protect

Motor Insulation.

Well done GA Petfood, it’s a pleasure for 3Phi Reliability

to work with a reliability focused Team.

Testimonial from GA Petfoods- Paul Leyland

AF500 fan cables were reading 26533counts with the TKED 1 , after i did the earthing on the cable correctly the readings reduced to 3944counts ,

after the crystalline cores fitted the readings reduced to 190counts.

Big drop from 26533counts down to 190counts , which proves the earthing and cores do the job of getting rid of cable interference .

Regards

Paul Leyland

Senior Electrical Automation Engineer GA Petfoods.

EMF Cores are fitted as close as possible to the VFD drive output eliminating radiated noise.

3Phi Reliability database shows that 37% of Motors utilize Variable Speed Drives, and account for 82% of Motor Insulation degradation. The High Frequency drive emissions attack motor insulation, therefore EMF Cores are an effective method of protection.

Note: Brushed & Insulated Bearings only provide protection after the High Frequency current has entered the motor.

Successful implementation of this technique has reduced the interference on Profibus communications. Here also the grounding needs are slightly different to cables to get the correct outcome.

Mark Gurney Motor Analyst

www.3phi-reliability.com