The availability of several technologies also allows us to perform Equipment Reliability Testing in which multiple technologies are applied to your equipment population in order to assist in accurately assessing current machine condition. Detailed reporting is provided on all findings.

Vibration Analysis has become one of the most widely applied of the Predictive Testing sciences. Reliability Testing Services offers this technology as a service in which programs are set up from “scratch” including establishing routes, monitoring frequencies, alarm limits, etc., or as a supplement to your existing vibration / testing program. Balancing and alignment services are offered on a per call basis. These services are performed by a Level 2 certified vibration analyst with 15+ years of field experience.

• The bottom spectrum shows a pump that was found to be misaligned and had the resulting worn coupling element.
• The top spectrum shows the same pump after it was precision aligned during a scheduled maintenance shutdown.
• Spectra were acquired at the pump input shaft.

While there are several other tests that may be performed on your motors, the following are offered as a sampling of what is available from Reliability Testing Services, Inc.

Power Quality Snap-Shot

This testing provides a snap-shot of both the circuit integrity and the power quality that is servicing a motor. High resistance connections in breakers, fuses, contactors, motor lug connections, and other locations can cause voltage and current imbalances that are detrimental to motor performance, and if left uncorrected, may result in premature motor failure. Power supply quality may also be a problem, especially in those cases where non-linear loads, variable frequency drives, excessive harmonics, or voltage imbalances exist.

Eccentricity

This test provides a snap-shot of positional relationship between the rotor and the stator as the motor operates under load. If the rotor is not positioned with respect to the stator windings so as to provide a relatively even air gap, asymmetrical magnetic fields can be produced. These imbalanced magnetic fields can cause undesired movement of the stator windings and electrically induced vibration resulting in pre-mature stator winding and bearing failure. Typical causes of this condition include loose or poor bearing / end bell register fits and “soft foot” mounting of the motor. This test offers excellent correlation to vibration analysis.

Rotor Testing

This test looks for anomalies in the rotor bars, rotor laminations, and the end rings of a squirrel cage induction rotor, and the field coils and windings of synchronous and wound rotor motors. High resistance, porosity, and breaks in rotor bars or end rings of squirrel cage induction rotors can cause excessive start-up currents and higher operating temperatures in a motor. Over a period of time, this can result in more broken bars, and eventually lead to stator damage or heat related failure. Analysis is performed at both the first and fifth harmonic levels.

Cracked rotor bars and bad rotor laminations

Sleeve Bearing

The sleeve bearing in the above example has worn to an oval shape. This resulted in a condition known as “oil whip”. The bearing has a “knock” that became very evident when recorded in the ultrasonic regions. Note the impacting that is evident in the waveform. Click on the play button below to listen!

SleeveBrgWhip