All power quality articles
Auditing power quality to detect harmonics, by utility in India using Fluke Series II Power Quality and Energy Analyzer
Troubleshooting the most common power quality problems—voltage distortion and harmonics. Tools needed, types of problems
This case history is a classic example of the importance of a systematic approach to solving a problem. It involves a contractor who works with several high-technology manufacturing plants.
The electrical power issues that most frequently affect industrial plants include voltage sags and swells, harmonics, transients, and voltage and current unbalance. The proper tools to correct these issues include knowledge and electrical test instruments ideally suited for each task.
Motor failures can be mysterious. Often, the mechanical loads on the motors have not changed and other loads connected to the same service appear to work normally - yet, the motors just fail.
When optimizing productivity in industry, energy use is one of the few inputs you can readily control.
“Let's just oversize the motor and we can run it lightly loaded—that will save us some money and be easier on the motor.” This is a false belief among some who select and install motors. Properly sizing motors for a given load results in driving loads more efficiently, saving energy, and saving dollars. Motors typically are most efficient when they are 90 % to 95 % loaded. Just because a motor says “25 Hp” on the nameplate does not mean the motor is producing twenty-five horsepower as it operates.Clamp meter readings: Problems and Solutions
Detect basic 3 phase power quality issues with the versatile Fluke 378 FC clamp meter for industrial electricians. Increase productivity and safety without test leads.
Healthy batteries should main¬tain a capacity above 90 % of the manufacturer’s rating; most manufacturers recommend replacing the battery if it falls below 80 %. A series of regular tests are recommended for ensuring that batteries are maintaining capacit
Many facilities, such as power plants or production facilities, depend on a strong preventive maintenance program. These programs are essential to keep processes running safely and efficiently.
What is power factor and why is it important? Learn how to calculate the power factor formula, each component of the equation, and why it matters.
Measure torque while motors are still in service using an advanced tool that eliminates external torque and speed sensors.
For three years in a row, a particularly large three-phase motor would fail twice a year. The facility maintenance manager called in both the electrical contractor and the motor manufacturer, who pointed fingers at each other but failed to resolve anything on site.
Because power quality issues are difficult to pinpoint, clients often reach the wrong conclusions about their power issues. That often leads to expensive solutions that don't actually correct the underlying problem.
Ever fixed something and still not solved the problem? Sometimes multiple deficiencies can all cause the same symptoms.
A large commercial building had just finished an elevator equipment upgrade - but they hadn't been able to bring the elevator back into normal operation.
This case history comes from an electrical contractor. Several of this contractor's clients operate large commercial buildings.
One winter morning, the electrician received a call from a local school. The caller said a transformer supplying power to three portable classrooms was making a chattering noise, as if something were loose inside.
This case history involves the investigation of a utility transformer failure that occurred in a rural area surrounded mostly by farmland and open space. The failure occurred in a location where power quality problems are rare.
In most facilities, lighting is a major element of operating cost. Part of that cost is due to energy, and part is due to maintenance.
The engineer carries a Fluke 43B on all trouble calls, because it provides a graphical display that allows customers to see a picture of the problem.
A small city gets its water from a mountain lake 30 miles away. A pumping system at the lake brings water up a short incline and into a long gravity pipeline that feeds the city's water distribution system.
Transformers supplying nonlinear loads should be checked periodically to verify operation within acceptable limits. Transformers are also critical to the integrity of the grounding system.
Ensure that your team has the tools it needs to reduce unnecessary repairs and increase uptime by integrating power monitoring sensors into your maintenance program.
The Fluke 1738 Advanced Three-Phase Power Logger automatically captures and logs more than 500 power quality parameters to give electricians and technicians more visibility into the data needed to make better power quality and energy consumption decisions.
Power reliability for facility managers (bottom line): top issues; adds, moves, changes; electrical and electronic loads; emergency power; older facilities
Since information technology (IT) installations are particularly sensitive to power supply fluctuations and distortions, they typically rely on an uninterruptible power supply (UPS) to compensate. Some installations even include a second UPS supplied by a separate feeder, and a standby generator that can be set to start automatically three minutes after detecting a power interruption.
Critical systems run smoothly with regular maintenance and reliable tools Everybody knows that consistent, dependable electrical power is critical to any plant's function. But perhaps even more critical is a reliable uninterruptible power supply (UPS) system. UPS systems are the silent partners that just sit and wait until there's a break in power. At that point, the UPS system is the most important system in the plant. It has to be ready to spring into action in milliseconds to keeps things running for anywhere from seconds to hours.
Troubleshooting an electrical panel overheating problem from unusual causes; testing with the power on, ruling out harmonics—and the resolution.
Monitoring three-phase power quality is a must. Whether you troubleshoot mysterious electrical problems or provide additional services to a client, it is three-phase power that is provided to commercial and industrial customers and three-phase power that is distributed throughout a facility.
Voltage stability may be a problem in areas where loads are cycling on and off during the day. Large compressors, motors, welding machines, arc furnaces, power factor correction capacitors and other large electrical machinery along with system impedance can easily cause voltage dips, swells, and transients.
To determine the best solution for mitigating unwanted harmonics, start by investigating the equipment suspected of producing the bulk of the harmonic currents. Most often these are Variable Frequency Drives (VFD's). Use measuring equipment to measure and analyze the frequencies and amplitudes of the harmonics. This is much simpler than it sounds.
Power factor correction capacitors reduce energy costs by avoiding the premium rates that utilities charge when power factor falls below specified values.
Downtime is costly, both in terms of patient wellbeing and monetary costs - the X-Ray, mammography, and other systems themselves cost millions and a failure can also idle technicians or surgical teams. Most of the facilities have motor/generators and can maintain operations independent of the utility, making the power system robust but also complex.
As we have seen, power problems have a bad effect on electronic devices. To detect a power problem, a technician will first check out the power supply to a device to make sure it is functioning properly.
In 2005, most facilities viewed their monthly electrical utility bill as a standard cost of doing business. When oil topped $100 per barrel, attitudes changed practically overnight, generating a surge of interest in energy-conscious retrofits that previously would not have been cost-efficient. Yet, when the energy costs came down, attitudes and practices did not entirely revert. The United States was still trying hard to shake a recession. Global competition for providing products and services had grown even more intense. American facilities had found a potential new source of margin and profitability in the form of their monthly energy bill, and they weren't giving it up.