Unexpected equipment trips are a common problem in industrial electrical systems. A machine may stop several times a week, a variable frequency drive may occasionally report an overvoltage or undervoltage fault, or sensitive equipment may restart without an obvious reason. In many cases, checking the equipment itself does not immediately reveal the cause.
The problem may be related to the power supply. Voltage dips, swells, transients, harmonics, voltage unbalance and other disturbances can occur for a very short period. If the electrical system is only checked with a standard multimeter, the event may already be gone when the measurement is taken.
This is where a power quality analyzer can be useful. Instead of looking at the electrical system only at one moment, it can record power quality parameters and capture events over a period of time.
Before connecting a power quality analyzer, first identify what is actually happening.For example:
A motor drive trips during startup
A PLC occasionally resets
Production equipment stops at irregular intervals
Lighting flickers when large equipment starts
A protection device trips without an obvious overload
Sensitive electronic equipment restarts unexpectedly
Equipment failures occur at roughly the same time each day
The timing of the problem is useful information.If a machine always trips when another large motor starts, for example, the investigation can focus on voltage changes during that period.If the trip happens randomly, longer-term data logging becomes more important.
The first measurement should establish what the electrical system looks like under normal operating conditions.
A power quality analyzer can be used to check parameters such as:
Voltage
Current
Frequency
Power
Power factor
Energy
Phase relationships
SUIN's power quality analyzer range is designed for measurements in three-phase power distribution systems, with different models covering different voltage, current, frequency and harmonic measurement requirements.
This initial measurement provides a reference for later event analysis.
A short voltage change can be enough to affect sensitive equipment.
A voltage dip may be caused by large load startups, faults elsewhere in the electrical system, or a sudden changes in the supply system.
A voltage swell is an increase in voltage for a limited period. The important point is that the voltage may look normal when an engineer arrives to investigate.
If the equipment has already recovered, a conventional spot measurement may show nothing unusual.
A power quality analyzer with event recording can capture these changes when they occur.
High-power loads such as large motors, compressors, pumps and welding equipment can change the electrical conditions of a facility when they start or stop. If an equipment trip occurs at approximately the same time as another large load is switched on, it is worth monitoring the system during that operating sequence.
A practical troubleshooting setup might involve:
Connecting the analyzer to the relevant distribution point.
Recording normal operating conditions.
Starting and stopping the suspected large load.
Comparing the electrical data before and after the event.
Checking whether the equipment trip corresponds to a recorded disturbance.
This approach provides actual measurement data instead of relying only on assumptions about the cause.
Harmonics are another possible source of power quality problems.
Modern facilities commonly contain nonlinear loads such as variable frequency drives, switching power supplies and other power electronic equipment.
These loads can introduce harmonic components into the electrical system.
When troubleshooting, look at:
Individual harmonic orders
Total harmonic distortion
Voltage waveform
Current waveform
Harmonic changes under different loads
A suitable power quality analyzer can help determine whether harmonic distortion is present and whether it changes when particular equipment is operating.
For example, SUIN's SA2200 supports harmonic analysis up to the 100th order, while other models in the range provide different harmonic measurement capabilities.
For three-phase equipment, merely measuring the average voltage is not sufficient, a comparison of the three-phase voltages is also necessary.
Voltage unbalance can affect motors and other three-phase loads, potentially causing abnormal operation or additional heating.
If a motor-related problem occurs repeatedly, record the three-phase voltage and current rather than checking only one phase.
The phase relationship and voltage unbalance data can help determine whether the problem is related to the supply system.
Some electrical disturbances are extremely short.
Switching operations, faults and other events can produce transient disturbances that may not appear in a normal voltage reading.
If sensitive electronic equipment experiences unexplained resets or failures, transient capture can be useful as part of the investigation.
The measurement requirements are different from ordinary RMS voltage monitoring, so the analyzer needs to have an appropriate transient measurement function and sampling capability for the event being investigated.
SUIN's current power quality analyzer range includes models offering transient measurement capabilities, with specifications varying by model.
This is one of the most useful functions when troubleshooting intermittent faults.
If an equipment trip happens once every two or three days, an engineer may not be present when it occurs.
Instead of repeatedly taking short measurements, the analyzer can be left connected to record selected parameters over a longer period.
For example, the monitoring period might cover:
One production shift
A complete operating cycle
Several days
A period when the problem normally occurs
The recorded data can then be reviewed to determine whether a power quality event occurred at the same time as the equipment fault.
SUIN's power quality analyzer range includes logger functions, while the specific recording capabilities depend on the model.
Finding a disturbance is only part of the troubleshooting process. The next question is where it came from. For example, if a voltage disturbance is recorded at a machine distribution panel, the engineer may need to compare it with measurements taken upstream.
This can help determine whether the disturbance is:
Coming from the utility supply
Generated elsewhere in the facility
Related to a large internal load
Limited to a particular distribution branch
The measurement location should therefore be selected according to the electrical system being investigated.
Electrical data becomes much more useful when it is compared with what the equipment was doing at the same time.
For example:
08:30 — Compressor starts
08:30:02 — Voltage dip recorded
08:30:03 — Production machine trips
This type of time correlation is much more useful than simply knowing that the system had a voltage dip at some point during the day.
For troubleshooting, always record the operating conditions alongside the electrical measurements whenever possible.
A useful investigation should record more than the abnormal value itself.
Keep track of:
Measurement location
Date and time
Equipment operating condition
Loads running at the time
Voltage
Current
Frequency
Power factor
Harmonics
Voltage events
Transients
Phase information
Duration of the event
This creates a more complete picture of the electrical system.
The required analyzer depends on the purpose of the measurement.
If the objective is a general survey or troubleshooting investigation, a Class S instrument may be suitable for applications where its measurement capabilities meet the requirement.
When measurements need higher accuracy and standardized, comparable results, a Class A power quality analyzer may be required.
IEC 61000-4-30 defines measurement methods and performance requirements for power quality measurement, with Class A intended for applications where accurate and comparable measurements are important.
SUIN offers both Class A and Class S power quality analyzer options, including the SA2200 Class A model and SA2110 Class S model.
Current measurement is another specification that should be checked before purchasing an analyzer.
The required current range depends on the electrical installation being tested.
SUIN's current product range includes configurations supporting current measurements up to six thousand amperes, with different current accessories available according to the application.
Before ordering, confirm:
Maximum expected current
Conductor size
Measurement method
Clamp or probe requirements
Number of phases
Required current range
Choosing the analyzer without considering the current measurement method can create problems during actual field testing.
Most industrial power systems operate at 50 or 60 Hz, but some applications require other frequencies.
SUIN's product range includes analyzers supporting 50/60 Hz and, on selected models, 400 Hz measurement.
The 400 Hz capability can be relevant to applications such as aircraft-related and shipboard electrical systems.
The operating frequency should therefore be confirmed before selecting a model.
Long-term power quality monitoring can generate a large amount of measurement data.
Reviewing everything directly on a handheld instrument may not be the most efficient approach.
PC software can make it easier to:
Review recorded data
Compare events
Analyze trends
Examine waveforms
Prepare reports
Store measurement records
SUIN's power quality analyzers are supplied with PQA View software for data analysis and reporting workflows.
When an electrical problem cannot be reproduced immediately, a practical workflow is:
1. Identify the equipment problem
Record when and how the equipment fails.
2. Establish normal conditions
Measure the electrical system when everything is operating normally.
3. Identify possible sources
Check large motors, drives, switching equipment and other major loads.
4. Set up event monitoring
Configure the analyzer to record the relevant power quality parameters.
5. Allow the system to operate normally
Do not change the operating conditions unnecessarily.
6. Review the recorded event
Look at what happened immediately before and during the equipment fault.
7. Compare different measurement points
If necessary, move upstream or downstream to determine where the disturbance originates.
8. Take corrective action
Once the electrical cause has been identified, the engineering team can determine the appropriate solution.
If you are purchasing a power quality analyzer for maintenance or field troubleshooting, check the following before making a decision:
Single-phase or three-phase measurement
Voltage range
Current range
50/60 Hz or 400 Hz support
Class A or Class S
Harmonic measurement range
Transient capture
Voltage dip and swell detection
Flicker measurement
Data logging
Storage capacity
PC software
Current probes and accessories
Battery operation
Safety rating
The best configuration depends on the electrical system and the type of problems you need to investigate.
If you are not sure which specifications are required for your application, you can provide SUIN with basic information about the electrical system and the measurement task.
Useful information includes:
System voltage
Single-phase or three-phase
Maximum current
Operating frequency
Equipment being tested
Expected power quality problem
Required monitoring duration
Whether Class A measurement is required
SUIN can then help you identify a suitable Power Quality Analyzer configuration and related current measurement accessories.
Troubleshooting an electrical problem is much easier when the measurement is made at the right time and at the right location.
A power quality analyzer can record voltage, current, harmonics, power quality events and other parameters that may not be visible during a short manual measurement. Long-term logging is particularly useful when equipment trips are intermittent and difficult to reproduce.
The key is to connect the measurement data with the actual equipment operation. Once the electrical event and equipment fault can be correlated, engineers have a much stronger basis for identifying the cause and deciding what to do next.
SUIN provides Class A and Class S power quality analyzers with different voltage, current, frequency, harmonic, transient and data-logging capabilities for power distribution testing, industrial maintenance and electrical troubleshooting.
Aug. 21, 2026
How to Use a Power Quality Analyzer to Troubleshoot Repeated Equipment TripsJul. 16, 2026
Power Quality Analyzer Buying Guide: How to Choose the Right ModelJun. 16, 2026
RF Signal Generator Selection Guide Based on Key Performance Specifications