Condition Monitoring Services

Rolling Bearings are vital components in various industries and ensure accurate and smooth rotation of equipment.
Various defects and failures can happen to them, which prevent their efficiency and proper functioning.
Bearing failure creates many parallel and simultaneous patterns. Full knowledge of these patterns helps us to diagnose their failure with sufficient confidence even without “having enough information about the bearing number”.

An example of vibration techniques for detecting bearing defects that we can use to correctly diagnose the failure and estimate its severity:

A- Frequency spectrum Symptom of Vibration velocity spectrum)
B-1 Vibration acceleration spectrum: Frequency spectrum Symptom
B-2 Vibration acceleration spectrum: Noise floor
C- Pattern of time signal Vibration acceleration
D- Frequency spectrum Symptom of acceleration envelope
E- Evaluation of the value or changes (trend) of the values of different parameters

Evaluation of the value or changes (trends) of parameters

Each parameter gives us a value that hopefully represents the health or failure of the bearing. Certainly, if this method (method E) is highly reliable, it will greatly reduce our work in reducing analyzes (methods A to D)

To use a parameter correctly, it is necessary to know exactly how it is calculated, because only in this case we will be able to have a correct understanding of its accuracy and the reason for its changes under different conditions.

In various industries, we have seen that the incorrect use of parameters has led to premature replacement of healthy bearings or even jamming of the bearing without warning.

For this reason, in the training course “BEARING DAMAGE VIBRATION ANALYSIS”, while testing several different failures, we examine the effect of failure severity and rotation speed on the values of different parameters.
We also examine the theoretical concepts related to these parameters and the conditions under which these parameters have errors.

Also, in order to increase accuracy, we will examine how to “simultaneously use” the “above techniques (A to E)” so that we can ensure the presence of failure and the severity of failure growth with sufficient confidence.

Today, different equipments offer different parameters according to their available signal processing and sensors:

In this brief article, we review some of these parameters:

BC- Skew- BCU -HDM- dBM- SFx-Spike Energy- Peak value-Crest Factor- Envelope Parameter

dBM parameter of the SPM Sock Pulse Method: Is calculated from the statistical analysis of the detected signals at very high frequencies.

HDM parameter: It is an improved method of dBM parameter.

BC parameter: It is the RMS value of acceleration signal with high-pass filter.

BCU parameter or Bearing Condition Unit: It is a parameter that expresses the condition of the high frequency vibration range.

The parameters extracted from the envelope signal: These parameters are depend on the demodulated acceleration signal in the considered frequency band. Considering that the signal is manipulated in the envelope process, the obtained units are not standard and different equipment use different units to express the value of the envelope signal. Such as: eu, Hdrp, gE, …

Kurt or Kutosis parameter: Kurtosis; the amount of transients in the vibration signal “tailedness” of the probability distribution of random variable.

Crest Factor parameter or sharpness index: It shows the ratio of the peak value to the RMS value. To diagnose bearing failure, this parameter is often checked in the acceleration unit.

RMS parameter: shows the RMS value of the signal. To detect bearing failure, this parameter is often checked in the acceleration unit.

Some of the out cases ostudy whose will be analyzed individually by candidates

Suggested Actions Based on Temperature Rise

This document has been prepared based on manufacturer instruction bulletins, NFPA, IEEE, NEMA and ANSI standards

An infrared electrical thermography survey can result in significant financial savings for the client by:

• Reducing the risk of an electrical fire.
• Reducing the risk of an unplanned electrical outage.
• Identifying priorities for planned maintenance, resulting in your spend going where it needed most.
• Determines if the elements and system have been properly installed and are not damaged
• Reduces downtime
• Reduces risk of equipment failure
• Increases safety
• Improves insurability
• Reduces liability exposure of the designers and installers
• Improves system performance
• Determines elements and systems carry out properly and meet the design intent
• Determines if elements and systems compliance with the project specifications and design
• Reduces construction schedule delays
• Saves money

Looseness is one of common defects that can be caused by excess design force.
Unbalance is one of the defects that the centrifugal force can cause many secondary defects, including looseness.
To fix the unbalance be sure to first remove all the secondary defects.
In the attached image, you can see that the unbalance has caused a loose between the bearing inner race and the shaft.
After fix the shaft loosening problem, the imbalance clearly showed itself.
After removing the imbalance, the vibration became normal.

Movie related to failure:

Detection of Stator Shorted-turns Fault in Three-phase Induction Motors using MCSA

The following is an excerpt from William T. Thomson’s book and VIBER X5 Application Notes No.1 (REV.A) Motor Current Signature Analysis

In fixed frequency, low voltage, main’s fed induction motors, it is generally accepted that there is normally no pre-warning of insulation degradation. It is normally the case that the insulation degradation in main’s fed, low voltage stator winding cannot be initially diagnosed via online measurements, and the first indication of a problem will be that a fault actually develops.

The concept that the rotor has already developed a fault and will need to be repaired has prevailed; hence, if it is a low voltage induction motor the often the approach is to let it run to failure.

However, in modern production processes any lead-time can be extremely advantageous since unexpected failure of a strategic. Low voltage, induction motor drive can be very costly, and, in some industries, it can be arranged for the motor to be replaced by a healthy one, and the faulty one is send for repair.
Generally, stator winding-related failures can be divided into five groups: turn-to-turns, coil-tocoil,line-to-line,line-to-ground and open-circuit faults.
Among the five failure modes, turn-toturn faults (stator turn fault) have to be considered the most challenging one since the other types of failures are usually the consequences of turn faults.