Dirty Power Quality

Dirty Power Quality

Is dirty power dirtying your profits?

In today’s manufacturing facilities, it is extremely common to find that there are large amounts of machinery that depends on high quality, clean electrical energy to keep it operating. Plant managers and technicians are often tasked with making sure this machinery is running at optimum levels to keep operating costs down. Wasted energy, downed machinery and dirty power can suck up your profits almost instantly. There is a very… Continue Reading »

Common Power Quality Issues

Power Quality Issues
Often times when dealing with a power logger or power analyzer you will see a waveform trend and maybe not be the most informed on what exactly it means. Below are the most common waveform patterns and a quick run down of what they mean as well as common causes and results of the waveform. JM Test is an authorized distributor of Fluke power analyzers and loggers. If you would like to rent or… Continue Reading »

Choosing the Right Ground Resistance Tester

Ground Resistance Tester

There are a wide variety of ground resistance testers available on them market today. These vary in design, features, and complexity, and include small handheld models as well as larger field instruments that are often packaged as part of a complete kit. These products also range in price, from few hundred up to several thousand dollars.

In this article, we discuss several critical questions to consider when selecting a ground resistance tester…. Continue Reading »

5 Key Steps to Perform a 30-day Load Study with Fluke Power and Energy

fluke power energy logger Fluke-PQ

When adding new loads to an existing electrical service or set of feeders, the first thing to determine is whether the existing system is capable of supporting the new loads. In other words, what is the highest load the system carries?

What you need to know

To determine existing equipment capacity, factor in the incoming conductor size, the ratings of the equipment, and space for new circuits. To determine present loading, you’ll need to either precisely… Continue Reading »

Digital Voltage Phasing Meter Part 2 – Phasing a Distribution Circuit

phasing tester digital voltage phasing meter

Digital Meter Provides Better Accuracy

Use the Hastings 6702 Digital Voltage Phase Meter to make sure you have voltage on both sides of power line switches/cutout fuses and check all the phases.  With the digital readout you see the small differences in the voltage reading.  Both sides of the cutout fuses should read zero volts but could possibly show 200-400 volt fluctuations.

HIpot Underground Cable

The purpose of hipoting underground cable is to… Continue Reading »

Digital Voltage Phasing Meter Part 1 – Potential Testing, URD Cable Testing

high voltage phasing sticks 6702

0-40KV Digital Volt Meter for Phasing Circuits

The Hastings 6702 Digital Voltage Phasing Meter consists of high voltage resistors encapsulated inside two fiberglass housings. These resistors are connected together with a coiled cord. A digital display is attached to one of the encapsulated resistor housings. Attach each encapsulated resistor to a hot stick of appropriate length for the voltages to be tested.

Measures overhead and underground voltages, Potential Testing and URD Cable Testing. Circuit Potential… Continue Reading »

Is My AC Rotor Bad?

Surge tester motor windings large

Can I Rule it In or Out as the Cause of Failure?

Rotor bar problems are infrequent, in most applications. But, when they occur, they are easy to overlook.  A lot of time is wasted on diagnosis when a rotor bar issue is not obvious.  The guesswork about rotor bars being good or bad can easily and quickly be eliminated for a motor that can run.

There are about 15 different ways to check for fractured… Continue Reading »

Transformer Testing with a Megger DLRO10HD

DLROHD10 digital low resistance ohmmeter

Avoid Unexpected Outages with Regular Testing

Regular testing of transformers can help identify problems that reduce system performance and can lead to unexpected outages. The dc resistance of a transformer winding can indicate the internal temperature of the winding when the resistance at ambient is compared to the hot resistance. The ideal test method is to make resistance readings at one minute intervals as the hot winding is cooling, using a Continue Reading »

Why Measure Low Resistance?

Digital low resistance ohmmeter Megger DLRO10HD

Megger DLRO10HD 10 Amp Digital Low Resistance Ohmmeter

Measuring low resistance helps identify resistance elements that have increased above acceptable values. The operation of electrical equipment depends on the controlled flow of current within the design parameters of the given piece of equipment. In the modern age of electronics, increased demands are placed on all aspects of electrical circuitry.

Low resistance measurements, with a unit like a Megger DLRO10HD 10 Amp Digital… Continue Reading »

How Insulation Resistance is Measured

Resistance Readings Considered Relative

You have seen that good insulation has high resistance; poor insulation, relatively low resistance. The actual resistance value

s can be higher or lower, depending upon such factors as the temperature or moisture content of the insulation (resistance decreases in temperature or moisture). With a little record-keeping and common sense, however, you can get a good picture of the insulation condition from values that… Continue Reading »

What Makes Electrical Insulation Go Bad, or Cause Insulation Degradation?

Insulation Degradation Can Be Fast or Slow

When your plant electrical system and equipment are new, the electrical insulation should be in top notch shape. Furthermore, manufacturers of wire, cable, motors, and so on have continually improved their insulations for services in industry. Nevertheless, even today, insulation is subject to many effects which can cause it to fail – electrical… Continue Reading »

How to Determine Phase Rotation on a De-energized Motor

Motor and Phase Rotation Tester – Megger

  • Complete phase-sequence and motor-rotation testing in one instrument
  • Ensures correct phase hookup in one easy test
  • Rugged and portable tester
  • Performs additional polarity and continuity checks


The Megger 560060 Motor and Phase Rotation Tester permits the electrical contractor or industrial maintenance electrician to permanently connect and tape the terminals of the motor being installed, without having to first energize the motor… Continue Reading »

Primary Injection Test System – SMC Raptor

Multifunctional Primary Testing System

The SMC Raptor C-05, C-15, C-25, C-35 is a smart test set designed as the definitive solution for the main primary test applications required in the commissioning and maintenance of substations, marking the difference with respect to existing equipment now being used. This new generation of primary injection test equipment makes primary injection testing easier, faster and more convenient.

The system consists of a Continue Reading »

6 Simple Steps to Design an Economical Grounding System

After taking your measurements and acquiring the resistance of a cubic meter of soil, we can calculate the depth needed for new ground rod installation in 6 easy steps using a Nomograph.

Step 1: select the required resistance on the R scale
Step 2: select the measured soil resistivity on the P scale
Step 3: take a straightedge and draw a line between the values placed  on… Continue Reading »

Cost Effective Method for Condition Monitoring of High Voltage Insulation for Transformers, Switchgear and Bushings


Tan Delta, also called Loss Angle or Dissipation Factor testing, is a diagnostic method of testing cables to determine the quality of the cable insulation. This is done to try to predict the remaining life expectancy and in order to prioritize cable replacement and/or injection. It is also useful for determining what other tests may be worthwhile.


Applications & Uses

Use Remote Measurements and Increase Safety for Dangerous Equipment

XCIEL XCiPhone4s

Take readings quicker and solve problems faster with simultaneous, recordable, remote measurements.

This video shows how to:

  1. take remote measurements away from dangerous equipment(60ft away)
  2. take multiple readings at the same time
  3. record those readings without writing them down
  4. see live measurements from multiple modules simultaneously on one screen
  5. measure AC voltage, AC current and temperature

This is a video that monitors an injection molding machine for quality issues on one of the heating bands while in… Continue Reading »

How to Take Multiple Electrical Measurements Remotely

How to Monitor an Electrical Panel without using PPE

This video shows how to:

  1. take measurements remotely away from dangerous equipment(60ft away)
  2. take multiple readings at the same time
  3. record those readings without writing them down
  4. see live measurements from multiple modules simultaneously on one screen
  5. measure AC voltage, AC current and temperature

This is a video that monitors an electrical panel for a Chiller. Normally we would use a power quality analyzer and proper PPE protection… Continue Reading »

What is Traceability?

Traceability can be defined as an unbroken record of documentation (e.g., “documentation traceability”) or an unbroken chain of measurements and associated uncertainties (e.g., “metrological traceability”). When we use the word “traceability” in this paper, we will always mean “metrological traceability.”

The National Institute of Standards and Technology maintains the U.S. national standards for temperature. In other countries, similar national standards laboratories perform the same function.

The readings of a thermometer  like a Continue Reading »

10 Dumb Things Smart People Do When Testing Electricity

Anyone who makes their living by working with electricity quickly develops a healthy respect for anything with even a remote chance of being “live.” Yet the pressures of getting a job done on time or getting a mission-critical piece of equipment back on line can result in carelessness and uncharacteristic mistakes by even the most seasoned electrician. The list below was developed as… Continue Reading »

How To Prevent Electrical Shocks Through Insulation Resistance Testing

Why Have an Insulation Resistance Testing Program?

A regular program of insulation resistance testing is strongly recommended to:

  • Prevent electrical shocks
  • Assure safety of personnel
  • Reduce or eliminate down time
  • Detect deterioration of insulation
  • Evaluate the quality of repairs

This type of program is helpful in identifying when to schedule repair work such as: vacuum cleaning, steam cleaning, drying and rewinding. Quality assurance standards are met before… Continue Reading »