December 28, 2005 A Prism Business Media Property Vol. I No. 5

CONTENTS
Boosting Your Maintenance Efforts

Electrical Troubleshooting Quiz

Reduce Downtime Through Preparation

Practical Implications of OSHA 1926.150

NEC on the Production Floor

Answers to Electrical Troubleshooting Quiz


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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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    The designations "National Electrical Code” and “NEC” refer to the National Electrical Code®, which is a registered trademark of the National Fire Protection Association.
     
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    Maintenance
    Boosting Your Maintenance Efforts
    Here are a couple of tips to maximize your maintenance program's efficiency.

    Schedule GFCI testing. Do you have a GFCI testing program? If not, people in your facility are at higher risk for electrocution than they otherwise would be. Just because the receptacle still provides power doesn't mean it provides GFCI protection. Testing a GFCI doesn't take long -- the real problem is doing it in the first place.

    In low-risk applications (e.g., a seldom-used receptacle in a low-traffic location), the odds may let you "get by with" a lax testing program for years (then again, they might not....). In high-risk applications (e.g., a receptacle next to an often-used sink), failure to have frequent testing is a bit like playing Russian roulette with only one empty chamber.

    Power events rank high on the list of GFCI failure causes. Following a power event, you should test GFCIs (prioritize by risk level). If your power monitoring system notifies you when an event occurs, you can initiate the tests in a timely manner. Here's a new strategy: As GFCIs fail, replace them with the self-testing models that have recently appeared on the market.

    Solicit operator input. Because operators spend far more time than maintenance people observing equipment operation, operators are potential goldmines for attentive maintenance organizations. An operator can inform you of strange noises and smells, odd vibrations, and other signs of trouble -- under actual operating conditions.

    An operator may suggest a different configuration or process arrangement that will reduce wear and tear. Such a suggestion may include equipment modifications to reduce unnecessary process steps -- which also increase output. Increased output is a selling point to department managers when you are trying to obtain the downtime needed to implement the change. Here's a quick tip: Ask individual operators to explain the process and how it might be streamlined.

    Showing operators that you respect them and value their input will encourage them to provide information and ideas from a perspective you simply do not have. This multiplies the brainpower of your maintenance organization -- at no cost to you. Yes, you'll have to filter out some "unusual ideas," but you'll also get gems you would otherwise miss.

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    Repair
    Electrical Troubleshooting Quiz
    A 100-hp motor has tripped its overloads three times in the past week. What are four possible causes, and how should you test for them?
    Reduce Downtime Through Preparation
    In a previous issue, we said you could reduce downtime by training a team on specific repair activities. But another answer is to move some repair activities "offline" from the downtime window.

    At one appliance plant, a critical assembly would throw a bearing every six to eight months, causing the entire output of the plant -- $250,000 an hour -- to stop. It took three hours to remove the assembly, rebuild it with new bearings (the one that failed and its mate), and reinstall the assembly. But less than half an hour of that repair involved removing and reinstalling the assembly.

    Maintenance solution. With a complete assembly as a spare in the stockroom, the repair downtime would drop from 3 hours to 30 minutes. While one team removed the old assembly, another team would retrieve and lubricate the replacement assembly. A new assembly cost $35,000 -- about 8 minutes of downtime. Total savings: about $1.3 million a year. Actual outcome: These savings didn't materialize because the division VP was obsessed with a stockroom inventory number. So the company continued to incur a $1.3 million loss every year.

    Assuming your management has its eye on the right goals, you can apply this mechanical example to electrical situations and realize a huge savings. Where you have electrical assemblies, you have an opportunity to reduce downtime. Added savings tip: Many electrical distributors think along these same lines, and one may already have a stockroom-ready solution waiting for you. Move assembly work outside the downtime window, and you reduce downtime.

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    Operation
    Practical Implications of OSHA 1926.150
    This addresses fire protection. Most of the provisions are one-time responsibilities or matters of policy. For example, once you install a sprinkler system, you satisfy the requirement to install one. But you still need to maintain sprinkler, alarm, and automatic extinguisher systems. Other provisions require periodic action, too. Manual fire extinguishers, for example, have these requirements:
    • Check them, by type, for appropriate application to the area in which they are located.
    • Keep inspections updated and documented.
    • Keep locations clearly marked and unobstructed from view and access.
     NEC on the Production Floor
    Walk into the typical industrial or commercial building, and an hour later you can walk back out with a hefty list of Art. 110 violations. In our previous issue, we discussed four common violations. Here are four more:
    • Inadequate lighting at service panels [110.26(D)]. You must provide illumination for all working spaces about service equipment, panelboards, and so on. Note the phrase "working spaces." This language implies the illumination is there when you are working in that space. Thus, providing the power source for the light from the same source as the equipment makes little sense. Think about the application in terms of illumination for work. What will it take to light that area so people can safely and efficiently service that equipment? While the answer may go beyond the letter of the Code, the practical implications are clear. And don't forget to provide receptacles for supplemental task lighting.
    • Violation of dedicated space above equipment [110.26(F)(1)(b)]. For some reason, the "dedicated space" above electrical equipment seems to attract HVAC, water, steam, and other utility pipes. What happens when you get a leak or a drip?
    • Unguarded equipment [110.27(B)]. The sight of a transformer bearing a "forklift scar" is all too common. Install bollards and other hefty protection, as needed, to prevent physical damage to electrical equipment.
    • No warning [110.27(C)]. If unauthorized people are entering equipment rooms, they are needlessly exposing themselves to the inherent risk. Also, unauthorized people have a tendency to treat equipment rooms as storage closets. Post adequate signage. OSHA also requires limited access to authorized personnel only -- via a lock [1926.403(j)(2)].

     Answers to Electrical Troubleshooting Quiz
    1. Wrong overloads. You can quickly eliminate wrong overloads as a cause. But don't increase the overload size just to prevent nuisance tripping -- an appliance plant that did that put itself in a 9-week shutdown. Use the correct overloads.
    2. Voltage imbalance. Measure voltage to ground on each phase. If you have a variance of 2% or more between any two measurements, power distribution issues are killing your motor.
    3. Low voltage. Check the voltage at the motor input terminals. The lower the voltage, the more current the motor will draw--this could be what's tripping your overloads.
    4. Motor insulation problems. Damaged motor insulation is a common cause of tripping, and of motor failure. Perform an insulation resistance test on the windings.
    There are several other potential causes, though these four are arguably the most common. If a motor trips its overloads, you need to examine the motor system methodically--otherwise, you risk catastrophic failure. A methodical investigation will address three areas: inputs to the motor (voltage, current, waveforms, etc.); the motor (environment, connections, balancing, alignment, mounting, etc.); and motor load issues (gearbox lubrication, motor/load alignment, motor/load type mismatch, etc.). NEC Figure 430.1 is a helpful guide.
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