by Howard Penrose, Ph.D., CMRP | Oct 24, 2020 | Electrical Reliability, Motors & Drives
As discussed in Parts I, II, and III about our ongoing literature searches and analyses of failure models associated with stator-winding defects, we have developed two theories surrounding the detection of faults in the stator. In one theory, the defect would be...
by Howard Penrose, Ph.D., CMRP | Oct 17, 2020 | Electrical Reliability, Motors & Drives
Following publication of Parts I and II of this series (Oct. 3, 2020, and Oct. 9, 2020, respectively), we continued our literature search for information on stator analysis (from academic and other types of technical papers). And, unfortunately, we continued to come...
by Ken Bannister, MEch (UK), CMRP, MLE, Editor | Oct 17, 2020 | Motors & Drives, RAM Tools & Methods
In the most basic of terms, an electric motor is a simple device that converts electrical energy into rotary motion that when transmitted to a driven load will perform mechanical work. If applied correctly, the motor will run effortlessly. If set up correctly, the...
by Howard Penrose, Ph.D., CMRP | Oct 9, 2020 | Electrical Reliability, Motors & Drives
In Part I of this short series (Oct. 3, 2020), we pointed to certain stator defects coinciding with specific signatures that have been presented through observation. Regarding the induction motor itself, while substantial research on the defect signature associated...
by Howard Penrose, Ph.D., CMRP | Oct 3, 2020 | Electrical Reliability, Motors & Drives
An area that has received limited research analysis within the topic of Electrical and Current Signature Analysis (ESA/MCSA) is the stator-slot signature. It’s been assumed for many decades that the number of stator slots times the running speed with different...
by Howard Penrose, Ph.D., CMRP | Sep 26, 2020 | Electrical Reliability, Motors & Drives
Over the past few decades, the general discussion in industry has been that you cannot perform offline electrical- or motor-current-signature analysis (ESA and MCSA, respectively) on equipment in no-load conditions. In fact, some publications have suggested the need...
by Howard Penrose, Ph.D., CMRP | Sep 17, 2020 | Electrical Reliability, Motors & Drives
In this week’s article on Electrical Signature Analysis (ESA), we discuss the issue of a 1X rpm current reading when dealing with belted applications. For this example, the motor is a 15 hp, 1765 rpm, 460 Vac, 18 Amp unit with 40 rotor bars (RB) and 48 stator...
by Howard Penrose, Ph.D., CMRP | Sep 11, 2020 | Electrical Reliability, Motors & Drives
While sometimes referred to as Motor Current Signature Analysis (MCSA), which involves collection of motor current data only, Electrical Signature Analysis (ESA) utilizes both voltage and current data. This includes values, phase impedance, power harmonics, and other...
by Howard Penrose, Ph.D., CMRP | Sep 4, 2020 | Electrical Reliability, Motors & Drives
Rotor-bar failures are not common in properly applied systems. In this short case study, we follow a 4000-hp motor without starting restrictions to rotor bar failure. Lessons learned include demonstration of the fact that load does not impact the relative...
by Howard Penrose, Ph.D., CMRP | Aug 28, 2020 | Electrical Reliability, Motors & Drives
Material wear is a primary cause of degradation of electric machines and driven equipment or powertrain. Wear is caused by either normal operation or abnormal conditions and is also dependent upon the type of equipment and application. The impact of wear in electric...
