Focal Points: Sponsored links

New CMMS! MVP Plant - Smart Software for Smart Maintenance

 Join The Association For Maintenance Professionals

RCM-EAM-MTrain-2009 Daytona Beach 

Infrared windows and safety products

Follow us on Twitter


Motor Testing Resources & Links

Knowledge Bases
Web Workshops

Photo Albums
Reliability Radio


Network Links

en Español
XML/RSS Feeds Advertise

Click to verify BBB accreditation and to see a BBB report.

Our privacy promise: We respect your privacy and never sell or rent our subscriber lists, a fact that is certified and audited by  Subscribing will not result in more spam! I guarantee it! announces the Top 100 list each year as a way of delivering value to our members and as a way of acknowledging the extra work that these companies put into creating a web site that contributes to the overall maintenance and reliability community.



Welcome!  Thank you for visiting the Motor Testing knowledge base.  This page contains links to many Motor Testing resources designed to improve your knowledge and skill.  We add new pages and resources often so stay current and please click here to sign up for our weekly email newsletters & Maintenance-Tips.

Featured Motor Testing Links

Specializing in Electrical Motor Maintenance Equipment
AC Motor Maintenance Distance Learning Course

Motor Testing Tip

Click here to find archived motor testing tips

iPresentation Online Training Session

Motor Testing Training

Click here to check the calendar for motor testing events
Motor testing books, tapes and CD ROM's


Managing the Complete Motor System
Dynamic Electric Motor Testing of DC Motors
Motor Repair Service Center Evaluation Guide


Calculating Motor Load With A Voltmeter and Ammeter 

Using the kVA/HP Code, A Voltmeter and Ammeter to Commission an Electric Motor  
Static and Dynamic Motor Testing as Part of a Predictive Maintenance Program
Electrical Motor Diagnostics for Generators
Part 1 – The Basics
Electrical Motor Diagnostics for Generators Part 2
The Multi-Technology Approach to Motor Diagnostics
Impact of Electric Motor System Maintenance and Management
Reconditioning a Flooded Motor by Howard Pensrose Ph.D
Considerations Before Investing in Condition-Based Monitoring Technologies for Motor System Reliability by Howard Pensrose Ph.D
Confused by NFPA 70E?  By John C. Klingler, P.E.
Basic Overview of RCM Based Approach for Motor Management Programs
by Howard W. Penrose

Electrical Motor Diagnostics: WIIFM: What’s In It For Me?
By Howard Penrose PhD, CMRP

Motor Testing - Which Road Will You Take?
by Dave Humphrey
Motor Management Help from Repair Shops through the Internet By Forrest Pardue and Dick Hancock
Motor Circuit Analysis Concept and Principle by Howard W Penrose, Ph.D.
VFD Fault Detection by Dave McKinnon Project Manager PdMA

Impulse Testing as a Predictive Maintenance Tool by E. Wiedenbrug SM IEEE, G. Frey M IEEE, J. Wilson, M IEEE,

Greasing Electric Motors Part 1 by Howard W Penrose, Ph.D.
Greasing Electric Motors Part 2 by Howard W Penrose, Ph.D.
Estimating Motor Life Using Motor Circuit Analysis Predictive Measurements: Part 1 by Howard W Penrose, Ph.D. (PDF requires adobe acrobat)
Estimating Motor Life Using Motor Circuit Analysis Predictive Measurements: Part 2 by Howard W Penrose, Ph.D.
Modern High Voltage Testing, by George Frey
Understanding the Tests that are Recommended for Electric Motor Predictive Maintenance by Curtis Lanham
AC Motor Rotor Bar Case History by Jim Zuidema (308k pdf)

Electrical Motor Diagnostics Business Case Development by Howard Penrose Ph.D. and Carol Vesier Ph.D.

Low Voltage Vs High Voltage Testing
by Dr. Howard W. Penrose, Ph.D.

Since the mid-1980’s, new technologies have been introduced that perform low voltage nondestructive evaluation of your electrical rotating machinery. Prior to this introduction, high voltage test method manufacturers would commonly caution users about the potential destructive tendencies of their technologies.

After this period, the story changed as the low voltage technologies took market share. The result? Marketing became the driving force with engineering the victim.

It is the purpose of this paper to discuss some of the myth and misdirection presented, and to reaffirm the direction of the industry. For de-energized Motor Circuit Analysis (MCA), the capabilities include: Cable faults; Winding shorts; Insulation to ground faults; and, Rotor/Air gap issues.

More...Click here to read Low Voltage Vs High Voltage Testing (107k pdf)

A Novel Approach to Electric Motor System Maintenance
by Howard Penrose Ph. D.

With the ever increasing frequency of corporate re-engineering, electric motor system maintenance programs have decreased. This has resulted in billions of dollars of lost revenue through increased electrical costs, downtime, and waste in industrial and commercial companies. Modern management practices often do not take into account the importance of maintenance to equipment uptime and energy costs.

The purpose of a successful electric motor system maintenance and management program is to improve equipment readiness and uptime while reducing capital
overhead. This program consists of particular maintenance and management tools designed to aid the maintenance engineer in electric motor systems and their care.

This book is sold for $119 and has been made available to exclusively to members in a pdf format at no cost!

Click here to request your copy (426k pdf)

Online Condition Monitoring of Motors Using Electrical Signal Analysis
Aditya Korde B.E. Diagnostic Technologies India Pvt. Ltd.

Motor current acts as an excellent transducer for detecting faults in the motor.  Spectrum analysis of the motor's current and voltage signals can detect various faults without disturbing its operation.  Typical faults that are detectable include:

  • Rotor bar damage

  • Misalignment/unbalance

  • Foundation Looseness

  • Static eccentricity

  • Dynamic eccentricity

  • Core damage

  • Loose wedges

  • Interturn shorts

  • Defective bearing

More...Click here to read Online Condition Monitoring of Motors  (355k .pdf)

Identifying the Motor Rotor Bar Related Peaks in a Spectrum
By Alan Friedman, DLI Engineering Corp

The motor bar peak in a spectrum appears at a frequency equal to the number of motor bars multiplied by the shaft rate of the machine. Although initially, most analysts will have no idea how many motor bars there are, identifying the peak that relates to the motor bars is fairly simple to accomplish. The reason for this is that the motor bar peak will have peaks on either side of it, spaced 120 Hz away (100 Hz where electrical line frequency is 50Hz). These peaks are termed “sidebands” and they are caused by the modulation of the motor rotor by the electromagnetic forces that cause the motor to spin.

More...Read Identifying the Motor Rotor Bar Related Peaks in a Spectrum (89k pdf)

Motor Repair's Impact on Efficiency

This paper summarizes the results of a motor rewind study performed jointly by EASA and the Association of Electrical and Mechanical Trades (AEMT) of the UK. The study covered motors of 10 different manufacturers ranging in size from 5.5 to 225 kW (about 7.5 to 300 hp). The motors were rewound under controlled conditions by Dowding & Mills PLC in the UK. Tests were conducted at the University of Nottingham in the UK.

More...Click here to read Motor Repair's Impact on Efficiency (556k pdf)

US Department of Energy Releases MotorMaster + Version 4.0

MotorMaster+ (MM+) is an electric motor energy and management tool that is provided at no charge by the US Department of Energy.  It supports motor management functions for virtually any sized facility and has also been designed for utility auditors, industrial energy coordinators, and plant or consulting engineers.  MM+ supports motor and motor system improvement planning by identifying the most efficient action for a given repair or motor purchase decision.

More...Click here to read about MotorMaster + Version 4.0 (23k pdf)

Basic Electrical Troubleshooting
By Pete Bechard, PdMA Corporation

A boiler feed pump being powered by two 3500 HP induction motors appears to be developing a problem. Failure of this pump will result in the loss of a generator currently producing half of the station’s power output. Operators are complaining that a large compressor on several occasions has failed to start. A controller just doesn’t sound the way it used to. A cooling fan has developed an audible “beat” sound during operation. One of the most enjoyable aspects of working as an electrician is taking such compelling evidence as “appears to be developing a problem,” determining what is actually going on, and making a sound decision on the correct course of action. Successfully troubleshooting a complex piece of equipment gives a technician a tremendous sense of satisfaction. Having an effective troubleshooting plan and following it can help obtain this feeling of satisfaction.

More...Click here to read Basic Electrical Troubleshooting (150k pdf)

Electric Motor Energy and Reliability Analysis Using the US Department of Energy’s MotorMaster+ by Howard W. Penrose, Ph.D, Jim Hanna, Johnny Douglass, Chris Cockrill, Greg Lee, Dave Van Horn

Energy efficiency in electric motor systems presents significant opportunities within industry. In a US Department of Energy report provided by Xenergy1, "In 1994, electric motor-driven systems used in industrial processes consumed 679 billion kWh – 23 percent of all electricity sold in the United States…. Implementation of all well established motor system energy efficiency measures and practices that meet reasonable investment criteria will yield annual energy savings of 75 to 122 billion kWh, with a value of $3.6 to $5.8 billion…" Reliability and maintenance practices on electric motor systems also provide an excellent opportunity for both energy efficiency and production cost avoidance2, "Drivepower users and utilities have made significant investments in recent years to improve the efficiency of motor-driven systems. The longevity of these measures – as well as the amount of energy they save – depends heavily on the quality of the maintenance they receive. Although it is usual to think of motor system maintenance as an activity that follows other drivepower decisions, it is actually the first step for most facilities in moving towards more efficient motor systems…The efficiencies of mechanical equipment, in general, can be increased typically 10 to 15 percent by proper maintenance."

More...Click here to read Electric Motor Energy and Reliability Analysis Using the US Department of Energy’s MotorMaster+ (239k pdf)

Variable Frequency Drive Motor Testing
by Noah Bethel,
PdMA Corporation

VFD Technology has changed the way most of us do business in one way or another.  If you have not been influenced in some way by this new technology, then stand by, your time is coming.  We have all heard the horror stories about motor failures occurring minutes or hours after applying a new drive, or seen the advertisements pushing us to demand the new inverter duty wiring to prevent these drive related motor failures.  What should you know and whom should you ask to get your answers? 

More...Click here to read Variable Frequency Drive Motor Testing (181k pdf)

Test Methods for Determining the Impact of Motor Condition on Motor Efficiency and Reliability
by Dr Howard W. Penrose, Ph.D.

This article discusses the financial impact of motor condition on electric motor efficiency and reliability by reviewing a combination of Motor Circuit Analysis (MCA) and vibration techniques. Cost impacts on energy, production and maintenance will be outlined. The primary areas of concern are phase balance, rotor bars, cleanliness and bearing issues.

More...Click here to read Test Methods (142k pdf)

Identifying Motor Defects Through Fault Zone Analysis
by Noah Bethel of PdMA

ELECTRICAL maintenance personnel have for years been limited to troubleshooting with no more than a fluke and a Megger.  This unfortunately does not provide enough information to allow most electricians to feel totally confident in determining if an electrical problem exists or not.  A mechanical operator once said, “If a problem exists with a piece of equipment, and there is an electric cable within ten feet of it, then it must be an electrical problem!”  If you are involved with electric maintenance you have probably heard at some time in your career, “It must be the motor.”  If you are into mechanical maintenance you have likely heard, “It’s probably the pump.  Let’s uncouple it.” 

More...Click here to read Identifying Motor Defects Through Fault Zone Analysis (168k pdf)

Electric Motor Monitoring and Diagnostic System
by Dick Roche

A new new on-line electrical diagnostic motor data acquisition system called MotorLink  has recently been released by FPS, Inc. The system is always at work monitoring and displaying electrical bus and load conditions to give engineers the earliest possible warning of motor related electrical deficiencies the instant they occur. It is a unique diagnostic system, in that all monitoring is done from one central location connected to the main bus. Motor start signature data is recorded using the company's patent pending wireless bus deductive technology that eliminates costly hardwiring to individual motor sensors, or the time consuming need to move diagnostic equipment from motor controller to motor controller to conduct off-line measurements.

Click here to read Electric Motor Monitoring and Diagnostic System (463k pdf)


MotorLink was installed on a 120,000 DWT tanker in late 2001.  During system testing for the Baseline Status Report MotorLink identified a problem with the Main Vacuum Pump. 

This is not a serious fault but it appears that it had actually been present over a three-year period.  This piece of equipment had been cited in the thermographic report each year since 1999.  Each year one of the engineers would clean and tighten the connections indicated in the infrared picture and would think that the problem was repaired.  The next year, the same fault would again be indicated by the thermography report.  When MotorLink was being installed the engineer advised that this item had just been repaired.

More...Click here for MOTORLINK CASE HISTORIES (603k pdf)

Eastman Chemical Company Motor Analysis…Stepping out of the Box  
Motor Circuit Analysis for Maintenance
Managing Motor Systems
Case History: 200 HP Electric Motor
Q&A on Motor Management Software with 24/7
Pump it up! Online Pump resources

Motor Testing and  Condition Monitoring Discussions

Check the MotorBlog for new posts
Click here to join the maintenance discussion forum

Find Motor Testing Vendors

Click here for a Directory of Suppliers

Search provided by and Google


List Your Web Site Editorial Policy Privacy Policy Contact us
Feedback © Copyright 2000-2008 NetexpressUSA Inc. All rights reserved Terms of Service Trademark Notice