bearing damage due to electric discharge

2020-2-11Author: Heiko Stache Manager Business Unit – Bearing Technology Sabine Petri Product Manager Klber Lubrication Conductive rolling bearing greases provide inexpensive and efficient solutions Whether in the plastics textile or motion control industries damage caused by electric discharge is a well-known issue and today it is more prevalent than ever 2020-8-17If half of all AC motor failures are due to bearing failure almost 80 percent of these are caused by electrical damage to bearings Strategies for Mitigating Shaft Current Damage As demonstrated above electrical damage to VFD/AC motor bearings begins at startup and grows progressively worse As a result of this damage the bearings

Bearing insulation prevents electrical current damage

2018-4-27Bearing damage can occur when electrical currents use the rolling contact as a conducting path Due to the relatively good metal-to-metal electrical contact only very high amperage currents such as welding currents are able to destroy the raceway surface electric discharges called EDM (electric discharge machining) currents will

Current through this path can damage the motor and load bearings as well as the motor-to-load coupling This current path would also include currents due to a transient voltage difference between the motor frame and the driven equipment To reduce bearing damage the preferred path (blue) for all these currents is the stator winding-to-ground path

2 Damage symptoms and possible countermeasures Typical signs of electrical corrosion include grey tarnished tracks in the raceways and on the rolling element surfaces Melt craters (Figs 1a and 1b) or fluting is also discernible mainly on the raceway surfaces Damage due to current discharge usually manifests itself in increased running noise

2020-2-6BEARING DAMAGE DUE TO ELECTRIC DISCHARGE ELECTRICAL DISCHARGE MACHINING OF BEARINGS Hugh Boyanton Shaft Grounding Systems Inc Oregon USA Abstract The frosted fluted or corrugated pattern often found on the surface of the inner or outer race of an an-

Bearing manufacturers estimate that approximately 50% of all motor failures are due to bearing damage and researchers have found that "Electrical Discharge Machining (EDM) bearing currents have been found as the main cause of premature bearing damages in Pulse Width Modulation (PWM) inverter fed drives " [March 2005 Journal of

Detection of Electrical Discharges in Bearings

2013-8-5Electrical erosion leads to bearing damage and consequently premature bearing failure The first stage of damage is not visible to the naked eye: micro craters due to the electrical discharge machining current phenomenon As shown below what happens is similar to spot welding a

2020-2-11Author: Heiko Stache Manager Business Unit – Bearing Technology Sabine Petri Product Manager Klber Lubrication Conductive rolling bearing greases provide inexpensive and efficient solutions Whether in the plastics textile or motion control industries damage caused by electric discharge is a well-known issue and today it is more prevalent than ever

2020-8-2The new Bearing Gard – with electrical grounding technology – dramatically increases electric motor reliability by guarding against the two main causes for premature motor failure: 1) bearing contamination and 2) damage due to electrical discharge The Bearing Gard is uniquely capable of resisting contamination at the entry point with its

2014-10-1This article documents the metallurgical evaluation of a rolling element bearing that failed due to electrical discharge damage This rolling element bearing was used in a helicopter turbine engine that failed in-flight resulting in a hard landing of the helicopter

Electrical erosion can be a very severe failure mode if found in a bearing due to the removal of material from the critical contacting surfaces and the high intensity vibration usually experienced Also the current discharge can damage the lubricant properties causing further damage to components

2015-4-1the bearing is sufficient to allow successful operation of the hydrodynamic film under expected loads static and dynamic as well as avoiding damage during the requitups and shutdowns The visual observations of the damaged bearing discussed in this paper provide the basis for calculating the loss of load capacity

2019-2-28result in bearing damage is welding If the sys - tem isn't grounded properly during welding additional voltages and currents are intro-duced which results in bearing damage Visual Identification of Bearing Damage Due to EDM Visual recognition is one of the key elements in determining whether EDM is the root cause of the bearing failure

We understand the devastating effects of electric motor and common mode noise and are proud to offer CoolBLUE Inductive Absorbers from MHW International Corp Versatile and high-performing these absorbers help to reduce bearing damage due to electrical discharge and extend system life in a huge range of applications including

Electric current damage — How bearings fail Part 2 of 6

The currents tend to heat bearing material to temperatures that melt that portion of the surface resulting in discolored areas where bearing material was re-hardened or melted or that produced small craters To prevent this type of damage you must prevent electric current from passing through the bearing

2019-9-9Case Study: Bearing Damage Due to Electrical Discharge Sep 9 2019 | Predictive Maintenance Vibration Analysis | 0 comments Like most industrial technologies Variable Frequency Drive (VFD) units have grown increasingly affordable over the past few years and have become common in many facilities to better control processes

Inverter-induced shaft voltages discharge to ground along the path of least resistance often running through the bearing system With electric motors operating as high as 16 000rpm the very thin grease layer between the rolling elements and race in a bearing can break down due

2012-6-4BEARING DAMAGE DUE TO ELECTRIC DISCHARGE ELECTRICAL DISCHARGE MACHINING OF BEARINGS Hugh Boyanton Shaft Grounding Systems Inc Albany OR Abstract The frosted fluted or corrugated pattern often found on the surface of the inner or outer race of an anti-friction bearing is often the result of electrical damage

2019-12-4an electric discharge machining (EDM) effect causing pitting of the bearing's rolling elements and raceways Initially these discharges create a "frosted" or "sandblasted" effect and usually the first symptom of bearing current damage is the audible noise created by the rolling elements riding over these pits in the bearing race

2018-2-14Electric motors are prone to many sources of damage some more common and some better known An increasingly common but still not too well known problem facing these motors is bearing current Bearing currents damage the ball bearings with electrical discharge machining (EDM) resulting in motor failure

Due to high voltage potentials across their surfaces the ceramic balls can also be pitted and eroded by electric discharge similar to "static electricity discharge" Damage to a generator's bearing race occurs for the same reason EDMs work: An electric current through the balls chisels away at the race metal