Dirty Power Quality

Is Dirty Power Dirtying Your Profits?

Today's manufacturing facilities rely heavily on machinery that requires a stable, high-quality electrical supply to operate efficiently. Plant managers and maintenance technicians are responsible for keeping this equipment running reliably while controlling operating costs.

Wasted energy, unexpected equipment failures, and poor power quality can quickly affect profitability. In fact, there may already be equipment in your facility experiencing electrical disturbances without anyone realizing it.

Poor power quality can affect a facility in two ways: it can damage or disrupt the equipment receiving power, and it can contribute to increased operating expenses through additional electrical losses, inefficient operation, and unplanned downtime.

When equipment fails, the costs extend beyond the initial repair. Facilities may experience reduced production, troubleshooting expenses, replacement costs, and additional labour required to restore operations.

Although power quality is sometimes overlooked during routine maintenance and troubleshooting, it can be an underlying cause of recurring equipment problems.

Modern power quality analyzers and loggers allow technicians to measure electrical conditions, identify disturbances, and determine whether the power supply is contributing to equipment performance issues.

For Canadian manufacturing facilities and industrial operations, monitoring power quality can help maintenance teams make better decisions about equipment reliability, energy performance, and preventive maintenance.

Where Do Power Quality Problems Come From?

It is easy to assume that plugging machinery into an electrical outlet or connecting it to a distribution panel automatically provides a reliable power supply.

However, electricity travels through several stages before reaching the equipment.

Power is generated, transmitted through electrical networks, distributed through utility infrastructure, measured at the facility's electrical service, and delivered through the building's internal wiring and distribution systems.

At each stage, electrical conditions can be affected by different factors.

Common power quality disturbances include:

• Voltage dips or sags: Temporary reductions in voltage that may cause equipment to reset, malfunction, or shut down.

• Voltage swells: Temporary increases in voltage that can stress sensitive electrical equipment.

• Electrical transients: Short-duration voltage disturbances caused by events such as switching operations or lightning.

• Harmonic distortion: Distortion of electrical waveforms caused by non-linear loads, including variable-frequency drives and electronic power supplies.

• Frequency variations: Changes in electrical frequency that may affect certain equipment and control systems.

• Voltage imbalance: Unequal voltage levels across phases that can contribute to motor overheating and reduced performance.

These disturbances can interfere with production equipment, industrial controls, motors, and other electrical systems.

Although problems may originate from the utility supply, many power quality issues can also develop within the facility itself.

Internal Causes of Poor Power Quality

Common internal causes include improper wiring, grounding or bonding problems, overloaded circuits, loose electrical connections, and changes in electrical loads.

Installing new machinery, replacing equipment, or modifying an existing electrical distribution system can also introduce conditions that affect power quality.

For example, adding equipment with variable-frequency drives or other non-linear loads may change the harmonic characteristics of an electrical system. Starting large motors may also create temporary voltage dips that affect nearby sensitive equipment.

External factors, including utility faults, switching events, severe weather, and disturbances on the electrical distribution network, can also influence incoming power quality.

For Canadian facilities operating in industrial and commercial environments, distinguishing between utility-side and facility-side problems is important before investing in corrective measures.

How Power Quality Affects Equipment and Operating Costs

Ideally, industrial equipment should operate consistently throughout its expected service life without unexpected interruptions.

In practice, repeated electrical disturbances can contribute to premature equipment failures, unexpected shutdowns, and reduced operational efficiency.

When a motor, drive, or control system begins failing repeatedly, the problem may not be limited to the equipment itself.

Poor power quality should be considered as one possible contributing factor, particularly when multiple devices experience similar problems or failures occur after changes to the electrical installation.

The financial impact may include:

• Unplanned production downtime

• Increased equipment repair and replacement costs

• Additional maintenance labour

• Electrical losses and reduced operating efficiency

• Damage to sensitive electronics and control systems

• Lost production caused by repeated equipment interruptions

Not every power quality disturbance directly increases electricity consumption. However, certain conditions, including harmonics, imbalance, and inefficient electrical operation, can contribute to additional losses and operating costs.

Identifying these problems early allows maintenance teams to address the underlying cause rather than repeatedly repairing equipment affected by the same electrical condition.

Using Power Quality Analyzers to Identify Electrical Problems

Power quality meters and analyzers help technicians investigate electrical disturbances by measuring and recording the conditions within an electrical system.

Depending on the instrument, these devices can measure AC voltage, current, frequency, power, harmonics, and other electrical parameters.

Many modern analyzers can monitor multiple phases simultaneously, providing a clearer picture of the electrical system being tested.

Some instruments also display voltage and current waveforms on a colour screen, allowing technicians to examine electrical behaviour in real time.

Waveform information and recorded measurements can help identify issues such as voltage dips, harmonic distortion, current imbalance, and unusual electrical events.

However, interpreting these measurements correctly requires an understanding of the electrical system and the operating conditions under which the data was recorded.

A single measurement does not always identify the source of a problem.

Technicians may need to compare measurements taken at different points in the system, review equipment operating patterns, or record electrical conditions over a longer period.

After completing repairs or corrective work, the equipment should be tested again using the analyzer. This helps confirm whether the original disturbance has been reduced or eliminated.

Retesting is important because replacing damaged equipment does not necessarily resolve the electrical condition that caused the problem.

Selecting the Right Recording Interval

Modern power quality loggers allow technicians to configure recording intervals and monitoring duration based on the type of investigation.

For example, certain instruments support recording intervals ranging from one second to fifteen minutes or longer.

The appropriate interval depends on what the technician is trying to measure.

Short Recording Intervals

Shorter intervals provide more detailed information about changes in electrical conditions.

They can be useful when investigating frequently changing loads, equipment operating cycles, or electrical disturbances that occur over relatively short periods.

However, collecting more frequent measurements generally requires more data storage.

Longer Recording Intervals

Longer recording intervals are often useful for monitoring electrical loads and energy consumption over extended periods.

For example, fifteen-minute averaging intervals are commonly used in electrical demand and load studies.

The original US article references NEC Article 220 in relation to fifteen-minute load-study intervals. Canadian facilities should instead follow the applicable Canadian Electrical Code requirements, project specifications, utility requirements, and equipment manufacturer guidance when selecting the appropriate testing methodology.

How Recording Intervals Affect Storage

Shorter logging intervals usually generate more data points, which can reduce the total recording duration available within an instrument's memory.

Longer intervals reduce the number of stored measurements and may allow the instrument to record over a longer period.

Actual recording capacity depends on the analyzer model, memory configuration, parameters recorded, and selected operating mode.

For example, the Fluke 1736 Power Logger supports user-selectable averaging intervals from one second to thirty minutes, allowing technicians to configure measurements according to the requirements of the investigation.

When planning a power quality study, it is important to distinguish between averaged logging measurements and high-speed event or waveform capture. A long averaging interval alone may not capture brief electrical transients.

Selecting the right recording settings helps ensure that the collected data is detailed enough to identify the suspected issue without creating unnecessary data volume.

Choosing the Right Power Quality Meter

Before purchasing or renting a power quality analyzer, consider the specific problem you are trying to investigate.

Some instruments are better suited to long-duration energy and load monitoring, while others provide more advanced capabilities for analysing voltage disturbances, harmonics, and electrical transients.

The appropriate choice depends on the electrical system, testing requirements, and level of diagnostic detail needed.

Consider whether you need to:

• Monitor voltage and current over an extended period.

• Investigate equipment shutdowns or voltage disturbances.

• Record three-phase electrical conditions.

• Measure harmonics, power factor, or energy consumption.

• Capture short-duration electrical events.

• Perform a load study before adding equipment.

• Generate reports for maintenance or engineering analysis.

The instrument should also have suitable voltage and current measurement ranges, measurement category ratings, and accessories for the intended installation.

JM Test Systems provides power logging and power quality testing equipment for industrial electrical applications. Contact the team to discuss suitable analyzer or logger options for your testing requirements.

Power Quality Loggers and Analyzers

JM Test Systems has featured several power quality testing instruments in its equipment portfolio, including:

• AEMC DL-1081 Data Logger (obsolete)

• AEMC PEL 103 Power & Energy Logger (discontinued)

• Amprobe DM-5 Power Quality Analyzer

• Fluke 1736 Power Logger

• Fluke 1750 Three-Phase Power Quality Recorder

• Fluke 435 Three-Phase Power Quality Analyzer

• Megger MPQ1000 Handheld Power Quality Analyzer (discontinued)

The suitability and availability of individual models should be confirmed before selecting equipment for purchase or rental.

Practical Takeaway

Poor power quality is not always obvious. Equipment may continue operating while electrical disturbances increase the risk of unexpected shutdowns, premature failures, or unnecessary maintenance expenses.

When troubleshooting repeated equipment problems, avoid assuming that the failed component is the only issue.

Start by identifying when the problem occurs, which equipment is affected, and whether the symptoms coincide with machinery startup, load changes, or other electrical events.

A power quality analyzer or logger can then help determine whether voltage disturbances, harmonics, imbalance, or other electrical conditions are contributing to the problem.

For Canadian industrial facilities, three practical steps can improve the investigation:

1. Identify the symptoms before testing. Record equipment failures, operating conditions, and the timing of recurring problems.

2. Choose the appropriate measurement method. Select a power quality analyzer or logger that can capture the suspected disturbances over a suitable monitoring period.

3. Verify the results after corrective work. Repeat measurements to confirm that the original problem has been addressed.

The objective is not simply to collect electrical data. It is to identify the conditions affecting equipment performance and use that information to reduce avoidable downtime, maintenance costs, and operational risk.

JM Test Systems offers power quality analyzers, power loggers, and related electrical test equipment. Explore available testing solutions or contact JM Test Systems to discuss your facility's requirements.