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42 Cards in this Set
- Front
- Back
Finding a potential problem ____? It shuts the system down is perhaps the best PQ scenario |
Before |
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It is usually wise to have the most ___? tool doing the monitoring until the source of the problem can be narrowed down |
Versatile |
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The digital multi-meter is useful for detecting ___? and unbalances or imbalances |
Voltage |
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A 3% voltage imbalance between phases may result in the need to ____? electric motors by 10% |
De-rate |
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Both voltage unbalance and harmonics are generally considered as ____? power quality problems |
Steady state problem |
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Short duration disturbances, such as sags, seeks and transients, are often not ___? By dmm type meters |
Detectable |
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Portable monitors use the ___? Approach to troubleshoot problems |
Reactive |
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What makes the infrared imager one of the most popular tools for PQ monitoring |
Don't have to make contact with what your measuring |
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What are infrared imagers used for |
Measure different temperature points in a system |
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What effect can a heating and cooling cycle have in equipment |
Loosen mechanical connections |
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A power quality instrument should be ____? For the anticipated range if the voltage and current levels |
Rated |
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Fallow all installation and operating instructions and only use accessories ___? For the instruments |
Approved |
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The installation, operation and maintenance of the instrument must be performed by ____? Personnel |
Qualified |
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When accurate measurements are needed on sinusoidal waveforms to detect ___? Only true RMS meters should be used |
Distortion |
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Connection to the voltage and current sources need to be made ____? And ___? |
Properly and safely |
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Connections between an instrument in the circuit need to be made in accordance with the type of circuit being monitored and with the correct? |
Phase relationship |
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Define transient |
Sub quarters cycle changes in the wave shape that usually do not trigger RMS variation (know this for the test) |
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Parameters such as ___? Do not need to be checked every cycle but they are useful to trigger an alarm when the approach limits are reached |
Power factor |
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Data collection and analysis will vary depending upon whether one is conducting a ____ or an ___? Exercise |
Audit and troubleshooting |
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What does the connection of PQ equipment at the point of common coupling help differentiate |
Isolate what comes from utility from what originates in the facility |
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Monitoring to establish a benchmark should be conducted for at least ___? To get a more complete picture of the electrical supply |
One week |
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Voltage ___? Can have a damaging effect on motors and other electromagnetic equipment |
Voltage imbalance |
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For benchmarks purposes, typically ____? And ___? Limits for sag and swell thresholds should be reset to ____? And ____? |
90% and 110%, 95% to 105% |
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List the requirements which should be included if they more complete energy audit is desired over a typical Benchmark study |
Individual phase values for Watts, volt amps, VARS, power factor, harmonic power, total energy, demand |
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The difference between service voltage and utilized voltage allows for ____? In facility wiring between the point of utility delivery and the utilization equipment |
Voltage drop |
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In general, transients with peak values ___? The nominal voltage sine wave peak come within the problem causing range |
1.5 to 2 |
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DC offsets more than a percent or two of the ____? Voltage can have adverse effects on transformers |
Nominal |
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The periodic cycling of energy demand is referred to as? |
On and off peak demand |
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The ratio of watts to volt amperes is known as ___? Power factor |
True. (know for the test) |
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You should be able to identify what problems of facilities equipment is experiencing after starting the monitoring program |
False, not after but prior |
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When multiple locations in the facility have exhibited problems that may be attributed to PQ phenomena what is the recommended best practice point to begin troubleshooting |
At the PCC, point of the common coupling |
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What is the likely direction or source of the fault condition if the current increases significantly when the voltage decreases |
Downstream towards the loads |
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For a ___? Load, the current will decrease proportionally to the voltage drop. For a ____? load, current will not decrease or increase proportional to the voltage sag or swell |
Linear and non linear |
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Where are customer power equality problems more likely to originate |
Inside customer facility |
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How can you determine if there is current running through a ground conductor |
Measure neutral to ground voltage |
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The ___? In two properly made ground connection causes current to flow in a ground Loop path with possible noise and or component failures |
Potential difference |
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Lowering the ___? Between the source and the supply can lesson flicker effects |
Impedance |
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Since fluorescent bulbs do not draw current ___? Lighting can be another source of PQ phenomena |
Linearly |
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An unbalanced transformer will cause ___? As will over voltage ___? Of a transformer |
Harmonics and saturation |
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____? Will cause the impedance to change, which will cause a device to draw different amounts of current |
Harmonics |
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____? Can cause physical damage to a computer semiconductors and capacitors |
Transients |
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In order to prevent premature failure, a motor should be de-rated due to which three findings |
Harmonic losses, negative sequence values, voltage unbalanced levels |