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February 12, 2007 A Prism Business Media Publication Vol. III No. 3



CONTENTS
Keeping Motors Efficient

Power Factor Correction

Electrical Troubleshooting Quiz

Repairs and Root Cause Analysis

NEC at the Facility

Unsafe Behaviors

Enter the "You Be the Electrical Inspector" Contest at the EC&M e-Tradeshow

It's Time to Hit the Beach

Answer to Electrical Troubleshooting Quiz


About This Newsletter
This twice-a-month
e-newsletter is brought to you from the publisher of EC&M magazine.

MRO Insider addresses topics such as:

  • Working with management and supervision
  • National Electrical Code® on the production floor
  • Safety procedures and programs
  • Troubleshooting techniques
  • Equipment maintenance and testing tips
  • Managing motors and generators
  • Trends in training and education
  • Managing energy use


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    Maintenance
    Keeping Motors Efficient
    The operating costs of the typical motor are about 98 times its purchase price. These operating costs are often higher than they need to be, due to inadequate or improper maintenance.

    To get more efficiency from existing motors:

    • Maintain the supply. Suppose someone asked you, "How much current leaks to ground on your motor supply cables, and what level of this is acceptable?" What would your answer be? How serious are you about inspecting and maintaining cables at 480V and above? This is only one aspect of maintaining the supply, but it's probably the most overlooked.
    • Maintain the input. Do you monitor the supply power current to your large, high-energy usage motors? If you aren't using your power monitoring system to look at motor feeder circuits, you are probably passing up easy energy savings.
    • Maintain the motor. Do you monitor and correct for motor vibration? Do you check alignment as part of your PM procedures? Do you inspect the mounting, grounding (bonding) connections, connection resistance, and other factors that contribute to energy waste? What about air filters? Do you follow the manufacturer's procedure for bearing lubrication?
    • Maintain the motor/load interface. If the motor and load are misaligned, you waste energy. Vibration monitoring and periodic alignment inspection are essential.
    • Maintain the load. Do you check the oil in motor gearboxes? If the oil is low or dirty, you can actually detect the energy waste by measuring the elevated temperature of the gearbox.

    Power Factor Correction
    This area of energy cost is seldom addressed correctly. Don't overlook these important issues.
    • If you are running the motor from a VFD, use a power factor corrected VFD.
    • If you are running the motor across the line, install power factor correction at the motor. Consider doing this with a power factor corrected VFD.
    • If you have ruled out a VFD, consider a softstart device. For large motors, this will provide a "domino effect" of failure prevention in your whole system. By eliminating the spike/sag cycling caused by starting large motors across the line, you'll extend the life of nearly everything in your facility. You will be able to see this effect in your feeder cable insulation resistance tests on any motor that is large in relation to your system.



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    Repair
    Electrical Troubleshooting Quiz
    A motor failed in the main production line, causing it to stop. You've already replaced the motor. Now you need to determine the likely cause. How should you proceed?

    The answer to this question appears at the end of this newsletter.

    Repairs and Root Cause Analysis
    A motor fails, bringing production to a halt. Your team swaps out the bad motor with a new one in what must be record time, and production is humming along once again. But was this a real repair, or simply a parts swap?

    A real repair solves the problem. A parts swap doesn't address anything but the apparent cause of production stoppage and the need to get running again. Thus, a parts swap won't prevent another production stoppage. The smoke rolling out of a motor is a good clue that its failure caused the production stoppage. But it doesn't tell you what caused that motor to fail. The real problem might even be in another part of the facility.

    Experts recommend root cause analysis, and we know this is the only proven way to solve failures completely. So, why don't we do it every time? One reason is urgency. Production managers want production up now. They don't want to wait while you make wishbone diagrams, conduct extensive testing, and develop a list of likely causes.

    So, don't make them wait. Do this "thinking work" now, while the equipment is running -- before you are in the pressure cooker. Develop a repair script for each item of critical equipment. The purpose of this script is to provide a sequence of troubleshooting steps that you can employ quickly when a failure occurs. Your repair script can be in any of several forms. The checklist format is simple, effective, and efficient. The flowchart format is another option. Don't worry about getting this perfect the first time.


    Operation
    NEC at the Facility
    Article 100 defines "energized" as being electrically connected to a source of voltage (or being the source of voltage). This definition fits the scope of the NEC (defined in 90.2). But it falls short when determining energy sources for purposes of safely working on equipment. You may need to isolate non-electrical energy sources, such as flywheels, gas cylinders, gravity-fed devices, hydraulic cylinders, mechanical springs, and pneumatic circuits.

    Unsafe Behaviors
    Most industrial accidents occur because of what people do, not where they are. Here are three unsafe behaviors your maintenance team should be aware of:

    1. Ignoring safety instructions. Signs, labels, checklists, MSDS, and other sources of safety information help prevent injury, but only if heeded.
    2. Assuming de-energization. Locking out a supply breaker doesn't guarantee a circuit is de-energized. Trust, but verify (using a meter rated for the power level in question).
    3. Hurrying. You've probably heard the expression, "Never enough time to do it right but always enough time to do it over." It's also true that your hurrying-related mistake can result in catastrophic failure, injury, or death. Take the time to do it right.

    Show & Events

    Enter the "You Be the Electrical Inspector" Contest at the EC&M e-Tradeshow
    Here's your chance to win a $100 American Express gift certificate and to prove your knowledge of the National Electrical Code by acting as an electrical inspector and citing every Code violation appearing in an actual electrical installation. Visit the EC&M e-Tradeshow, a virtual online exhibition and live conference center. Also available is a live conference scheduled for February 15th on "Ground-Fault Coordination" and a special presentation by Generac on "Sizing Commercial Generators." And take a look at the archive of various past conferences, such as "Claim Litigation" and "Harmonics: Causes, Symptoms, and Remediation Techniques."


    It's Time to Hit the Beach
    If it's your job to make sure all systems are "go," you need to go to Electric West. This show and conference offers the right information and product mix to meet all of your information needs. Do you maintain and operate electrical systems in a facility? If so, you have to make plans to attend the Electric West conference program in Long Beach, Calif. Check out this event's 40+ seminars in the areas of power quality, safety, Code changes, and industrial applications, and make plans to meet 200+ leading suppliers. Or register now.


    Quiz Answers
    Answer to Electrical Troubleshooting Quiz
    This motor is obviously a critical one, or its failure would not have stopped production. So, determining the likely cause is also critical. The worst time to be thinking about the troubleshooting procedure is when production is already down.

    During a failure, you should be able to use a troubleshooting procedure specific to this motor. Your first step in developing this procedure is to develop a list of every asset (e.g., supply breaker, motor drive, etc.) related to the motor. Note the asset ID and location of each asset. Your next step is to develop the likely failure mode of each of those assets and what tests to conduct for each failure mode. While production is still up, you should walk through this procedure as if you are actually troubleshooting. This will help you find checkpoints not apparent from your asset list.


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