In any electrical installation, some current will flow through the protective ground conductor to ground. This situation is usually called leakage current. Leakage current mostly flows in the insulation surrounding conductors and in the filters protecting electronic equipment around at home or at the office. The problems occur when leakage current on circuits protected by GFCIs (Ground Fault Current Interrupters) causes unnecessary and irregular tripping. In most cases, it can cause a rise in voltage on accessible conductive parts.

Insulation has both electrical resistance and capacitance as it conducts current through both paths. Even with the high resistance of insulation, little current can actually leak. However, if the insulation is old or damaged, the resistance is lower and ample current may flow. Moreover, longer conductors with higher capacitance cause more leakage current. At GFCI breaker manufacturers, they recommend one-way feeder length to be limited to 250 feet (76.2 m), maximum.

On electric equipment, it contains filters intended to protect against voltage surges and other disruptions. These filters typically have capacitors on the input, which adds to the overall capacitance of the wiring system and the overall level of leakage current.

For more leakage current basics and its measurement and effects, head on to https://presidium.ph/ for the high-equipment insulation testers to prevent future leakage current. Get a quote now!

Safety is the utmost important reminder to anyone who works with or around electricity. It manages what you wear, how you work, and the tools you carry. And by tools, we mean all the tools you carry, not just battery-operated test tools. 91% of electrical workers approved that insulated hand tools are the most critical when working on electrical equipment. From electricians to utility workers and maintenance to HVAC technicians, they carry insulated hand tools such as screwdrivers, pliers, and cutters along with the best electrician tools.

When working around electricity, the thing to remember is to de-energize the equipment, however, that’s not the case. Sometimes nearby energized equipment has unknown energy pathways that might unexpectedly feed voltage into the equipment you’re working on.

Insulated hand tools safety

When hazardous and unpredictable situations occur, insulated tools provide an extra measure of protection against it. And high quality insulated hand tools are engineered to protect you from electric shock and reduce the possibility of arc faults caused by short circuits.

The NFPA 70E standard requires insulated tools to be used when working on or near electricity greater than 50 V as this will protect workers from possible injuries and avoid companies from paying fines and liability costs from accidents.

It is perilous to understand the difference between a regular hand tool and an insulated tool. With lots of hand tools containing rubber coating over plastic handles, it is far different from an insulated hand tool. High quality insulated hand tools are constructed of a special combination of materials that can block potentially hazardous voltages and protection against electric shock.

Insulated tool certification

In using insulated hand tools, one must be certified and must undergo stringent testing by third-party labs to prove that the protection works and the tools can withstand hard use, extreme temperatures, and even live flame. Importantly, they must also comply with international standards including IEC 60900 and ASTM F1505.

The level of protection that Fluke engineered for the new line of insulated tools goes beyond research. An application from the same stringent requires safety, reliability, and ergonomics to our insulated hand tools that we require of our handheld test and measurement tools. They are precision-engineered of CMV steel for superior durability and manufactured using the most advanced techniques in state-of-the-art facilities in Germany.

Safe and ergonomic

Fluke insulated hand tools are also designed to minimize wear and tear. They are ergonomically designed to adjust to your hand to diminish strain and weakness and help prevent repetitive motion injuries. Our insulated pliers and cutters give you more gripping strength and are slim enough to more easily access jammed junction boxes and panels.

When working with live equipment and not sure how much will protect you from your regular hand tools, get one now from Presidium’s Insulated Hand Tools. Visit https://presidium.ph/ for the high-quality insulated tools for easier work and for your protection.

How did you measure ac accurately before there were true-rms DMMs? There were three kinds of precision rms meters available to me. The available types were all analog; the electrodynamic, the iron vane, and the thermocouple. They were all fragile, requiring careful handling to achieve accurate measurements and avoid damage. They were also slow to respond and presented a significant load to the measured circuit.

How different it is today, with many digital multimeters featuring true-rms ac measurement capability. Today’s meters are rugged, respond quickly, are more sensitive, and present the results with easy to read, digital clarity. But there are some subtle points you should be aware of when making rms measurements.

Most DMMs today measure the ac-coupled true-rms signal, rejecting the dc component if any is present. A few models, such as the Fluke 189, offer the additional option of measuring ac+dc true-rms, calculating the total rms value with the dc component present. Why the difference? When should you use one versus the other?

In a properly operating power distribution system supplied through transformers, only ac should be present, so the ac-coupled measurement offered by most DMMs is appropriate. And, when a diode fails in a motor drive rectifier circuit, it’s usually more effective to detect the failure by observing a reading in the dc voltage function which rejects the ac component.

Then, there’s the case where you would like to trace an audio signal through an amplifier circuit. That signal might exist on the collector of a transistor where a dc bias current is also present. Here again, when you want to separate the ac and dc components, the ac-coupled mode of the DMM is the correct one to use.

One case for measuring ac+dc occurs in the output of unfiltered dc power supply where a significant ac ripple voltage is present on the dc signal. Since a resistive heater or incandescent lamp connected to such a supply will respond to the total energy available, an ac+dc measurement will more accurately indicate how the load might react.

What can you do if you have only the ac-coupled rms measurement capability in your DMM and you want to measure the combined ac and dc energy? Bring on the calculator.

You can first measure the ac voltage and then the dc, recording both values. Next, you square both terms and add these squared values together. Finally, you take the square root of the sum and you have the ac+dc true-rms value of the signal.

A variation of this technique may be used to investigate the ac output of an electronic motor drive by using the low pass filter function available on the Fluke 87V.

The primary signal of interest on the output of such a drive is the low-frequency signal that drives the motor. The low pass filter of the 87V isolates this signal so you can make accurate measurements of its frequency and true-rms voltage.

When you don’t use the filter, you get a much higher reading, because the measured signal now includes all the switching voltages used to create the motor drive voltage.

To determine the rms value of this difference, you can do the following:

1. Measure the total voltage and record the value.
2. Measure the voltage with the low pass filter on and record that value.
3. Now, square both terms and subtract the second squared value from the first.
4. Finally, take the square root of the result and you will have the true-rms value of all the excess energy that was not filtered, within the bandwidth of the meter’s input.

One case where rms results may be added or subtracted directly is at your household panel, where the sum of the two 120V legs is indeed 240V. Those two signals are coherent. Visit https://presidium.ph/ to get a compact true-rms meter for accurate electrical installation and troubleshooting.

Oscilloscopes track signals as they shift over time and indicate the signals on display. The amplitude of the signal is indicated on the vertical axis and time is shown on the horizontal. The device plots a graph of the instantaneous signal voltage as a function of time. In order to analyze waveform traces meticulously, here are the four characteristics of the waveform that you should look for amplitude, time, waveform shape and distortion, and waveform distances, specifically from the outside sources.

Here are the common variations to look for:

Symmetrical shape

Continuous waveforms should always be symmetrical. If there is an instance wherein you have to print traces and cut them into two pieces, both sides should be identical. A small difference can cause a problem. If the two components of the waveform are not symmetrical, there may be a problem in detecting the signal.

Rise and fall, edges

Specifically, with square waves and pulses, the rising or falling sides of a waveform can immensely impact the timing in the digital circuits. It may be essential to lessen the time per division to see the edge with greater resolution. The use of cursors and gridlines will help you measure the rise and fall times of leading and trailing edges of a waveform.

 Amplitude

Always double-check that the intensity of amplitude is within the circuit operating requirements. Test the constancy, from time to time. Meticulously track the waveform for a long period of time; also monitor changes in the amplitude. Use horizontal cursors to identify if there are any amplitude fluctuations.

 Noise or glitches

When waveforms are acquired through active devices such as transistors or switches, transients or other incongruities can have a result of timing errors, propagation delays, bad contacts, or another incident. Noise will overlay the acquired signal and it will be difficult to see the real data behind the noise. I can be generated externally from DC-DC converters, lighting systems, and high-energy electrical circuits.

Excessive ringing

Ringing can be visible most of the time in digital circuits and in radar and pulse-width-modulation applications. It occurs at the transformation from a rising or falling side to a flat dc point. Test for immoderate ringing, balance the time base to provide a clear illustration of the transition wave or pulse.

Momentary fluctuation

Momentary changes in the measured signal are usually the result of external causes such as sag in the main voltage, invigoration of a high – power device that is attached to the same electrical grid, or a loose connection. Use the ScopeMeter to watch the acquired waveform for a long period of time to depict the main cause of the problem.

Drift

Minor changes in a signal’s voltage over time can be difficult to detect. The change is slow that it is hard to distinguish. The changes and aging of temperature can impact passive electronic components which are resistors, crystal oscillators, and capacitors. The drift in a reference dc voltage supply or oscillator circuit is one of the main factors to diagnose.  Sometimes the only option is to track the calculated value (V dc, Hz, etc.) over an extended period of time.

In summary, it is necessary to practice good troubleshooting skills to save time and simplify the process of determining common waveform variation before the problem occurs. Try to discover more about troubleshooting methodology and make it a habit to always document key waveforms and measurements for future reference. Interested in getting an Oscilloscope? Get yours now at https://presidium.ph/?s=oscilloscopes

The frequent failures with single-phase motors include a centrifugal switch, thermal switch, or the capacitor. Though these problems can be easily be addressed, it is essential that you check if the model you have is aged 10 years or less or more than 1 HP, and if not, then it’s time for an upgrade.

How to troubleshoot split-phase motors?

The split-phase motor has both starting and running winding. The starting winding is automatically removed by a centrifugal switch as the motor starts kicking though in usual cases, a thermal switch that has a manual and automatic reset is often used as it automatically turns off the motor when it starts overheating. The risk could be that the motors may restart at any time.

Troubleshooting procedures:

1. Turn off the power and inspect the motor. Immediately change the motor if it is damaged or burned.
2. Check if the thermal switch is at manual mode and if it is, restarts it and turn motor on.
3. If the motor opts to start, use a voltmeter to check for voltage if it is within 10% of the listed voltage and other motor terminals. If it is incorrect, you must troubleshoot the circuit leading to the motor or if correct, simply turn motor off and test. We recommend you use our Fluke 87V Industrial Multimeter for full efficiency.
4. Turn off the combination starter and lockout and tag starting mechanism per the company’s policy.
5. With the power off, connect Fluke 87V to the same motor terminals the incoming power leads were disconnected from. The ohmmeter will then read determine the resistance of the starting and running windings. Since the windings are parallel, the combined resistance is less than the resistance of either winding alone. It is indicative that you immediately change the motor if it reads zero, then there’s a shortage or reads infinity, then an open circuit is present.
6. Check the centrifugal switch for signs of burning or broken springs. If it has, changes the switch and if none, inspect it with an ohmmeter.

Troubleshooting capacitor motors

Troubleshooting capacitor is the same way as troubleshooting split-phase motors, only the additional device which is the capacitor has to be considered. A capacitor motor is a split-motor with another one or two capacitors. These capacitors give the motor more starting and running torque.

The common issue with capacitors is that it deteriorates fast. It has a limited life and without you knowing, it could already have a short circuit or an open circuit. So it is obvious that you will have to change it more often. You must be cautious that if these failures with capacitors are not immediately addressed, it may cause your motor to burn out or not start at all.

Capacitors are either oil or electrolytic and made with two conducting surfaces separated by a dielectric material. It is a medium to maintain an electric field with little to none outside energy supply. It is usually used to insulate the conducting surfaces of a capacitor.  Furthermore, an oil capacitor is sealed in a metal container and the oil serves as the dielectric material.

Between oil and electrolytic capacitors, electrolytic are more often used. It is formed by winding two sheets of aluminum foil separated by pieces of thin paper impregnated with an electrolyte. The electrolyte is used as the dielectric material as it acts as the conducting medium through a current flow by ion migration.

The aluminum foil and the electrolyte is sealed in a cardboard or aluminum cover but note that it must have a vent hole to prevent possible explosion if the capacitor is overheated or shorted.

Troubleshooting procedures:

1. Turn off the combination starter and lockout and tag starting mechanism per the company’s policy.
2. Measure voltage using Fluke 87V at the motor terminals to make sure the power is dead.
3. Capacitors are found on the outside frame of the motor. Remove the cover but in this process, be cautious as the capacitor may hold charge though the power is off.
4. Check for leakage, cracks, or bulges. Replace if found.
5. Remove the capacitor from the circuit and discharge it. In order to safely discharge it, place a 20,000-ohm, 2 W resistor across the terminals for five seconds.
6. After discharging, connect Fluke 87V leading to the capacitor terminals. The device will determine the condition of the terminal to be either good, shorted, or open.

Visit our website at www.presidium.ph to know more about our products.

It may happen as a surprise for some that electronics-related problems in buildings are often rooted back to power problems.

Almost every major subsystem in today’s commercial buildings has some type of solid-state electronics installed. These include HVAC units with an electronics board in its control panel. Regardless of what system type it may be, their common denominator is electronics.

Another issue can occur due to old vs new electronics as some electronic equipment in buildings are installed 20 or more years ago, which can be more prone to issues over time. Being electronic systems, they are all susceptible to problems due to power even if some electronic manufacturers can claim an amount of tolerance to power problems to their products.

Typical power scenarios

Knowing these common scenarios can be valuable as these are repetitive and can sometimes even occur more frequently.

Lightning strike

A lightning strike is a common scenario but will obviously vary depending on your location and climate. Flashes of Lightning can cause a lot of problems, and because HVAC equipment and a lot of the building electronics are located on the roof or outside of the building, it is vulnerable to lightning strikes.

The effects of lightning strikes can be fatal as the electronics can be completely wiped out, with visible burn marks and a burned smell. A good way to prevent such an occurrence is to move the electronics and to install better lightning protection and grounding.

Power loss & Generation Testing

Power loss is another common problem and can be caused by a multitude of reasons such as utility problems, maintenance lapses, and device surges to name a few. Depending on the condition of power loss, there is a chance that the electronic device may not recover properly even when power is restored.

When power loss occurs, the backup generator will start after a short delay. Power surges may also occur along with voltage or current problems when generators start. This can cause electronic circuit problems. This is a common issue that electronic devices have a problem after the generator test is performed.

If a system is critical, a small UPS is installed at the electronic device power supply. This ensures that the device doesn’t meet a power failure and can offer some form of surge protection. Another tested technique is to reboot the device by removing power until it is completely shut down, before turning the power on again.

Utility Problems

The power utility is also one of the root causes of problems with electronic devices. The nature of these problems is more systemic, and ongoing which makes it harder to solve. In some cases, they can be unique as some utilities will not readily acknowledge power problems. If the problems are repetitive with no direct correlation to lightning strikes, the usual suspect is utility problems.

One of its main indicators is the location of the utility power feed as some utilities feed power to a building from a substation that is distant or has other big customers. Having more than one customer on the same power feed will manifest itself through power problems for the building. Often the buildings will have the same symptoms or power problems.

The best solution for utility problems is to install power quality measuring equipment to find out the problem and where it occurred. This can help in asking for an adjustment or reimbursement to the electronics.

Power problems are detrimental to electronic devices. The power supply of the building must be checked by a power technician to ensure that it is working properly. Untreated power problems can lead to the failure of these electronic devices which can affect operations of the building systems.

Electric motors are the key factor in many industrial processes and can account for up to 70% of the total energy consumed in an industrial plant and consume up to 46% of all generated electricity worldwide. Given their precarious nature for industrial processes, the cost of downtime associated with failed motors can be tens of thousands of dollars per hour. Ensuring that motors are efficient and operate reliably is one of the most important tasks that maintenance technicians and engineers face daily.

In many circumstances, energy efficiency can mean the difference between profitability and financial losses. And, since motors consume such a significant portion of energy in industry, they have become the main target for generating savings and conserving profitability.

Traditional motor testing methods

Calculating electric motor performance and effectiveness in traditional methods should be well distinct. However, the process can be inflated to set up and difficult to apply in working processes. To measure electric motor efficiency both the electric input power and mechanical output power must be established over a wide range of dynamic operating conditions. The traditional method of measuring motor performance first requires technicians to install the motor into a motor testbed. The testbed consists of the motor under test, attached to either a generator or dynamometer.

During testing the load is varied to determine the efficiency over a range of operating modes. The testbed system may seem straightforward but there are several essential disadvantages:

1. The motor must be removed from the service.
2. The motor load is not truly representative of the load the motor serves while in service.
3. During testing, the operation must be suspended (creating downtime) or a replacement motor must be temporarily installed.
4. Torque sensors are expensive and have a limited operating range, so several sensors may be needed to test different motors.
5. A motor testbed that can cover a wide range of motors is expensive and the users of this type of testbed are typically specialist motor repair or development organizations.
6. “Real-world” operating conditions are not taken into account.

Electric motor parameters

Electric motors are designed for specific kinds of applications depending on the load, and each motor has different characteristics. These characteristics are classified according to the National Electrical Manufacturers Association (NEMA) or International Electrotechnical Commission (IEC) standards and have a direct effect on the operation and efficiency of the motor. Each motor has a nameplate that details key motor operating parameters and efficiency information in accordance with either NEMA or IEC recommendations. The data on the nameplate can then be used to compare the requirements of the motor against the true operating use mode.

A new approach

The Fluke 438-II Power Quality and Motor Analyzer provide a modernized and cost-effective method for testing motor efficiency while eliminating the need for external mechanical sensors and costly downtime. The Fluke 438-II, based on the Fluke 430-II Series Power Quality and Energy Analyzers, has its full capability to measure power quality while also measuring mechanical parameters for direct-on-line electric motors. Using data from the motor nameplate (either NEMA or IEC data) coupled with three-phase power measurements, the 438-II calculates the real-time motor performance data including speed, torque, mechanical power and efficiency without the need for additional torque and speed sensors. Also, it directly calculates the motor de-rating factor in operating mode.

The data required by the Fluke 438-II to perform these measurements is entered by the technician or engineer and includes the rated power in kW or HP, rated voltage and current, the rated frequency, rated cos φ or power factor, rated service factor and motor design type from the NEMA or IEC classes.

How it works

The Fluke 438-II unit provides mechanical measurements (motor rotating speed, load, torque, and efficiency) by applying proprietary algorithms to electrical waveform signals. The algorithms combine a mixture of physics-based and data-driven models of an induction motor without requiring any of the pre-measurement testing typically needed to estimate motor model parameters, such as stator resistance. Motor speed can be estimated from the rotor slot harmonics present in the current waveforms. Motor shaft torque can be related to induction motor voltages, currents and slip by well-known but complex physical relations. Electric power is measured using the input current and voltage waveforms. Upon obtaining torque and speed estimates, the mechanical power is computed using torque times speed. The motor efficiency is computed by dividing the estimated mechanical power by the measured electric power. Fluke conducted extensive testing with instrumented motors driving dynamometers. Actual electric power, motor shaft torque and motor speed were measured and compared to the values reported by the 438-II to determine accuracy levels.

Summary

Taking critical motor efficiency measurements is simplified by eliminating the need for external torque and separate speed sensors, making it possible to analyze the performance of most industrial motor-driven processes while they are still in service. This gives technicians the ability to decrease downtime and gives them the opportunity to trend motor performance over time, giving them a better picture of overall system health and performance. By trending performance, it becomes possible to see changes that may indicate forthcoming motor failures and allow replacement before failure. For best Fluke 438-II in the Philippines, check out our products at https://presidium.ph/product-category/products/fluke-industrial-group-tools/power-quality/.

Above anything else, safety in-home or workplace has to be a priority. According to OSHA and NFPA 70E, to ensure safety especially in a workplace, workers must de-energize all energized parts to which they will be exposed unless required for troubleshooting.

It may seem easy to place electrical equipment in an electrically-safe work condition but actually there’s more to it than just that, there are several factors you need to consider.

Planning

Proper planning is safety’s friend. A rigid and detailed plan before diving into the process makes everything easier and you will be freed from any harm. In this case, it will make testing simpler and safer.

Risk Assessment

A risk assessment has to be done. This is required by NFPA 70E 110.1(G) Electrical Safety Program, 130.1 Working While Exposed to Electrical Hazards, 130.4 (A) Shock Risk Assessment and 130.5 Arc Flash Risk Assessment.

Free from distractions

Before going into the process, workers must be fully prepped with tools and equipment and must be secured to their body to avoid falling off or any other possible distractions that might destroy the focus and might lead on to possible accidents.

Traffic in the area

Anything that isn’t necessary in the workplace must be put somewhere safe or things like barricades or barriers, vehicles or forklifts must be strategically positioned to exact places so it wouldn’t cause traffic. This is because these are factors that cause substantial hazards and if not attended to readily may pose threats or accidents.

Secure Work Permit

A secured Energized Electrical Work Permit is also required by NFPA 70E Section 130.2 (B). In this section, it indicates the assessments that are needed to be done, required PPE and precautionary measures in the work zone.

Given these factors to ensure safety in the workplace, workers must also remember these things before taking a single measurement.

• Is this troubleshooting for the absence of voltage?
• What required test instruments are needed?
• Is a safety backup required? Do workers need training for CPR/use of an AED?
• Where will the safe work zone be established?
• What personal protective instruments are needed?

In testing for the absence of voltage which will verify if the voltage isn’t present before the beginning of work, you might also need to consider a non-contact proximity tester.

Running around the business in the vicinity of an electrically-active workplace, precautionary measures are absolutely needed. But before you go into the process of testing, be sure to be equipped with the right tools and equipment like professional digital meters to keep you away from harm or possible accidents. Visit us at www.presidium.ph to get the best and quality-assured digital multimeter for your business.

Cheers to developments in technology, thermal images are now more affordable, easier to use and better deployed in industrial and commercial markets than ever before. ­­

This is a pleasant development for contractors looking into adding thermal imaging into their services, as most customers would have likely heard about thermal imaging and how it can improve their business.

Thermal cameras as the name suggests, produce thermal (heat) pictures of equipment which enables you to have a powerful demonstration to display indications that your equipment is about to fail.

For contractors, your edge is your experience in handling different types of equipment and failure scenarios. Like any troubleshooting scenario, the person using the thermal camera should draw on experience to analyze and understand the readings. With this, you can easily identify if the reading indicates that the electrical panel is hot and whether you should investigate the connections or the load.

Additionally, thermography is also helpful for regular maintenance and troubleshooting. It can easily help you identify which facility and units are critical to performance.

Thermal tools can easily be a part of your regular site inspections or during troubleshooting calls.

To maximize the effectiveness of your thermal imaging tools, it is also advisable to enroll in courses from reputable trainers on how to use them. This will give you a competitive advantage if you decide to offer thermal imaging as part of your services, as you will have the credentials, theoretical and practical knowledge on how you can get the best results from your thermal camera.

Here are just a few things on what you learn about in thermal imaging training:

• How to use the thermal camera
• Applications with the greatest return on investment
• How to properly perform inspections
• How to interpret results and generate meaningful and actionable reports
• How to safely conduct thermography inspections in an industrial work environment

Source: Fluke.com

In summary, it would be beneficial for contractors to be equipped with thermal cameras. To maximize your investment in buying one, make sure that you take the time to train on the basics of using it and train by learning by using the tool to improve your services. Remember, the more you use, the more familiar you become in using thermal imaging tools. Visit our website at www.presidium.ph to know more about our products. GET A FREE DEMO https://presidium.ph/contact-us/

Thermal imagers aren’t your typical cameras. In addition to the standard lens that comes with it, most of them are compatible with other optional lenses as well. Changing the standard lens with a macro, telephoto, or wide-angle lens effectively gives you a different camera. This means it can give you more range and accuracy in capturing images anywhere, whether it’s right across you or hundreds of feet away.

One camera for everything

While a standard lens can do the job perfectly for occasions such as performing a general inspection of electrical equipment around a factory, you’d be limited should you need to scan a larger area like the ceiling or roof of a factory or warehouse. A wide-angle lens would be needed in such cases and it would be really useful if you are also a home inspector and you would need to scan the outside of a house. When it comes to scanning overhead vents or ductwork or high power transmission towers, a telephoto lens is your best bet which can allow you to work from the ground. An infrared camera can do all of that, with all the lenses packed into one single camera.

Importance of infrared lens material

It is important that the lenses you use are engineered for the most efficient transmission of energy to the detector. The first choice for the quality of infrared lenses is Germanium because it is transparent in the infrared spectrum and has a high index of refraction. Germanium lenses are protected by engineered coating, provide the most efficient material to transmit energy to the detector, making high-quality infrared images.

If you can get “smart” add-on lenses that can be swapped and used among multiple compatible cameras without any special recalibration for each camera, you can save a lot of time and money in being able to quickly swap out lenses for whatever the situation calls for. For best Fluke Ti401 PRO Thermal Camera, get a demo at https://presidium.ph/product-category/products/fluke-industrial-group-tools/infrared-cameras/.