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Articles: Motor and Power System Testing

A Better Understanding of Rotor Dynamics and Support Stiffness

More Data Provides More Answers

by Ron Brook

A Closer Look at Air Gap Eccentricity

by Douglas E. Swinskey & Peter M. Bechard

The first step in evaluating test data is understanding the relationship to the circuit's Fault Zones and how abnormalities in a specific Fault Zone affect the performance of the motor. The six Fault Zones (Power Quality, Power Circuit, Stator, Insulation, Rotor, and Air Gap) are derived from the most common electrically related motor failures in industrial environments. The Air Gap Fault Zone describes the measurable distance between the rotor and stator within the motor. Air gap eccentricity is a condition that occurs when a non-uniformity in the air gap between the rotor and stator exists.

 

A Cradle to Grave Approach - Motor Management at Its Best

by Noah Bethel, CMRP

Ask a motor manufacturer how long one of its motors is expected to live, and the response will be something like, "20-plus years in the right environment." Ask the same question in a facility that uses such a motor and the answer is more likely to be, "If we get five years out of it, we'll be happy!" Why does this discrepancy exist? Why do motors die of an infant mortality instead of living to the ripe old age for which they are designed and built? The answer has to do with the failure to optimize motor management and maintenance.

 

Adventures in Engineering Standards - Behind the Scenes of Creating IEEE Std 43-2000

by Howard W. Penrose, PhD, CMRP

Engineering can be a boring career with everyone working with known measurements and absolutes. There is never any doubt that the information contained in a standard or textbook is fact because everything is static, mathematical, and measurable. At least, that is what most people tend to think.

Applying Power Quality Measurements to Predictive Maintenance

You may already be using predictive maintenance (PdM) techniques on your motors and drives. But how often do you inspect the power to your equipment? By adding basic power quality measurements to production equipment maintenance procedures you can head off unexpected failures in both production equipment and your power system.

Are you smarter than your electric motors?

Test your knowledge with this PdMA Sponsored Quiz on Electric Motors.

Are You Treating Machinery Failures or Curing Them?

by Joe Van Dyke

A critical motor‐driven fan develops a fan end bearing defect that threatens to cause an unplanned outage in a critical plant operating process.

Assessing Transitions to Benchmark Performance - A Multi-Level Perspective

Daniël A. Lachman and Roy Tjoen A Choy

This article provides a different perspective on the difficulties experienced by companies that try to achieve business excellence.

Companies are seen as socio-technical entities that have ruling regimes that are path dependent (in their routines, beliefs, infrastructures, strategies, etc.) and thus hamper the adoption of practices that propagate efficiency, reliability, productivity, etc. A "heuristic device," such as the multi-level perspective originating from science and technology studies, is presented as a tool for managers, consultants and other analysts to decipher sociotechnical entities in order to identify landscape factors, regimes and niches (the locus for innovation). This will enable them to discover bottlenecks and opportunities for transitions of companies towards viable alternatives.

 

Defects in Nonceramic Insulators: Can They be Detected in a Timely Manner?

by S. Gorur and S. Sivasubramaniyam Department of Electrical Engineering, Arizona State University, Tempe, AZ, USA

This work was performed under a PSERC (Power Systems Engineering Research Center) funded project at Arizona State University

This paper is a continuation of the work reported during the Daycor users meeting. The electric field measurement method has been explored to determine its potential for timely detection of defects in nonceramic insulators. Various types of defects were simulated and the external electric field was computed. It is shown that the electric field method used presently is not sensitive enough to permit early detection of defective. There is a need for an improved method, perhaps periodic corona inspection could be the answer.

 

Diagnosing Rotor Bar Issues with Torque and Current Signature Analysis

by Drew Norman

Over the years rotor bar problems have been a diagnostic challenge for motor maintenance professionals.  Now with current signature, spectral torque analysis and automated computer diagnostic software, defining rotor health problems has been made fairly simple.  However, problems arise when professionals do not understand the underlying principles of the what’s, whys and how’s of dynamic rotor testing.

Evaluating Winding Connections With Infrared

Introduction

An area that is often overlooked in the rewinding of an electric motor are the internal connections of the winding. Most coils have multiple wires making up one ‘conductor' (Figure 1). The reason for this is to allow the wire to be more flexible for installation while allowing enough cross section for the amount of current that the conductor must carry. This generates a situation where improper brazing, crimping or other methods of making the connections will generate a hot-spot due to IR losses.

Guidelines to a Good Motor Repair

A Good Motor Repair is a Two-Way Street

created through a collaborative effort led by Advanced Energy

In the late 1990s a group of industry experts worked collaboratively to produce a document that any facility can use to better understand and communicate with their motor repair vendors.  This group consisted of utilities, government, motor manufacturers, and the motor repair industry and energy efficiency advocates.  Each participating company is noted in the resulting document “Guidelines to a Good Motor Repair.”  

Implementing ESA as Part of Your Predictive Maintenance Program to Improve Electrical Reliability

By William Kruger

Why Predictive Maintenance?

PART 1

Predictive Maintenance (PdM) resulted from studies that determined that Preventive Maintenance (PM) programs are only efiec-tive for the 11 percent of machine failures that are age related. This means approximately 89 percent of machine failures are random in nature and time-based maintenance programs are inefiective on these random types of failures.

Implementing ESA As Part of Your Predictive Maintenance Program to Improve Electrical Reliability

PART 2

William Kruger

This is a follow-up to the article that was published in the Dec/Jan 2012 issue of Uptime.
Click here for PART 1

Premier on ESA

Abstract

This is the second part of a series of articles discussing using electrical signature analysis (ESA) to improve a plant's electrical reliability. This article was written to give those not familiar with spectrum analysis the basics to read and interpret the graphs and displays used in spectrum analysis. It also introduces some basic analysis techniques to begin using ESA to identify developing problems in the motor system that could lead to either a loss of production or an increase in maintenance costs.

Improved Reliability Through Electrical Motor Testing

Electrical Motor Diagnostics at Romulus Engine Operations

by Richard Scott, Mike Nault, Mike Anaple, Cheryl Murphy, Sam Richardson and Ken Breece

Electrical motor diagnostics (EMD) as practiced at Romulus Engine Operations includes off- and on-line motor testing. It also includes acceptance testing of new and repaired electric motors prior to storage or installation, tracking and correction of minor defects during the lifecycle of the system, tracking of issues related to the motor repair or new motor vendors, and route-based testing of critical motors.

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