by Howard Penrose, Ph.D., CMRP | Feb 13, 2022 | Asset Management, Electrical Reliability
During the 1990s, the U.S. Department of Energy (USDOE, energy.gov) and industry partners developed additional methods for load and efficiency testing that could be easily performed in the field with standard electrical instruments. While they may not be as exact as...
by Howard Penrose, Ph.D., CMRP | Feb 7, 2022 | Asset Management, Electrical Reliability
In 2010, an independent study was conducted at Dreisilker Electric Motors (Glen Ellyn, IL) to compare field-efficiency-testing methods to laboratory methods. Investigators used the U.S. Department of Energy (USDOE) MotorMaster Plus 4.0 (MMPlus) and a commercial ESA...
by Howard Penrose, Ph.D., CMRP | Jan 30, 2022 | Asset Management, Electrical Reliability
One of the more interesting issues with which we’ve been wrestling since the early 1990s is how to evaluate the efficiency of an electric motor in the field. Sounds simple, but even now, the discussion continues among academia, manufacturers, end-users,...
by Howard Penrose, Ph.D., CMRP | Jan 23, 2022 | Asset Management, Electrical Reliability
As with most industries, electric-motor repair has good and bad actors. I remember part of my training with Dreisilker Electric back in the early 1990s. If we lost a repair job to a lower-cost service company, we would take a current reading at a specific load and...
by Howard Penrose, Ph.D., CMRP | Jan 10, 2022 | Asset Management, Electrical Reliability
In most of my articles, the terms Electrical Signature Analysis (ESA) and Motor Current Signature Analysis (MCSA) have been interchangeable. There are, however, differences in how the in-depth analysis of both voltage and current views the system versus just the...
by Howard Penrose, Ph.D., CMRP | Jan 2, 2022 | Asset Management, Electrical Reliability
As noted in Part IV of this series (see link below), determining the potential life of a machine can be relatively complex and, thus, call for some detailed experimental studies. In this series installment, we will review the potential life of the insulation on a...
by Howard Penrose, Ph.D., CMRP | Dec 4, 2021 | Electrical Reliability, RAM Tools & Methods
A bearing fails in a variable frequency drive (VFD) application. The response is to apply a shaft brush and insulated bearing. A critical electric motor shorts to ground. The response is to rewind or replace the motor and continue business as usual. When equipment...
by Howard Penrose, Ph.D., CMRP | Nov 27, 2021 | Electrical Reliability, RAM Tools & Methods
In Part III of this article series (Nov. 20, 2021, see link below), we discussed common and linear-type failure modes from mechanical systems as represented in the P-F curve. Mechanical equipment fails in terms of a “natural log” hazard curve,...
by Howard Penrose, Ph.D., CMRP | Nov 20, 2021 | Electrical Reliability, RAM Tools & Methods
If you follow topics on reliability, you may have the impression that all equipment is born, lives, and dies in the same pattern as Europeans in the 17th century. That would be with a high rate of death at birth and during their early years, average across the middle...
by Howard Penrose, Ph.D., CMRP | Nov 15, 2021 | Electrical Reliability, RAM Tools & Methods
One of the most powerful and straightforward measurements of equipment reliability is Mean Time Between Failure (MTBF), which lets the reliability engineer roughly estimate conditions surrounding a system. Some will criticize the use of MTBF as a reliability tool...
