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Harmonics

Harmonics – where do they come from?

Harmonics can cause all sorts of problems: tripped relays, failed transformers, damaged capacitor banks and even cracked motor shafts. But where do they come from, and how do you cure them? Non-linear loads like low-energy lights, VSDs, switched-mode power supplies...

Why does cable length between VFDs and motors matter?

It is an undeniable fact that frequency inverters provide the most benefits of the many methods of controlling induction electric motors. However, in some cases the use of a frequency inverter can have a negative effect on the motor....

The surest way to diagnose high-voltage surge arresters

Surge arresters play a key role in protecting electrical devices and equipment in high-voltage electrical substations. Like other devices, they must be periodically diagnosed. The most common method is visual inspection: checking that the arrester has no visible external...

Electrical Power Explained – Part 4: Unbalanced three-phase AC power

In our last blog, we described how balanced three-phase AC systems act like three independent single-phase systems. There's no neutral current, and the total active and reactive powers are just the sum of the active and reactive phase powers....

Five key test points to understand motor drive efficiency and performance

Motor drives are a well-known technology for transforming the constant voltage from the main ac power supply into a voltage that varies to control motor torque and speed ideal for motors that are driving mechanical equipment loads. Motor drives...
transformer failure

What causes a transformer to fail?

Symptoms of power quality issues include vibration, excessive buzzing or humming and overheating. Technicians should occasionally check the power of transformers that supply nonlinear loads, such as variable frequency drives (VFDs) or switching power supplies. Doing so ensures operation...

Why clean power is critical to smooth operations

When optimizing productivity in industry, energy use is one of the few inputs you can readily control. The consequences of poor power quality, such as power factor and harmonics, can not only be a direct hit on the bottom line...
solar panel

DC injection the new source of trouble

Grid connected photovoltaic systems are growing in importance as sustainable energy sources. The DC power of the solar panels is converted into an AC power by inverters. These are transformerless and, besides generating AC current, also inject a small DC...

Energy efficiency and ISO50001

To improve energy efficiency in industry, the International Organization for Standardization has developed the voluntary ISO50001 energy management standard. This is similar to the ISO 9001 quality management standard. Systematically and regularly checking the efficiency of electric motors can...

Find problems early by monitoring motor and drive efficiency

More than 40% of industrial motors work at or below 40% of their load rating. That means poor power factor and inefficient operation. Efficiency of all motors can drop over their lifetime, which increases energy and maintenance costs and...

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Choosing the right current clamp

Many users of an energy logger, power logger or power quality analyzer usually use the tool’s supplied current clamp in their application. Since the...

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