Harmonics
Harmonics With the increasing use of power electronics and non-linear loads such as variable-speed drives, computers and other IT equipment, uninterruptable power supplies, or arc welding for example, the power system is getting more and more polluted. This is causing power quality problems such as harmonic distortion, low power factor, unbalance and flicker among other disturbances. The focus of this article is harmonic distortion. Power electronic and non-linear loads draw distorted currents due to the switching nature of the equipment. The distorted current is composed of a...
Read MoreVariable Speed Drives
What is a variable speed drive ? A variable speed drive varies the motor’s frequency and voltage to control its speed. The basic schematic of a variable speed drive system is shown in Figure 1. It normally consists of an AC/DC converter and an output DC/AC PWM controlled three phase output. When using a variable speed drive correctly one can obtain very accurate speed control of the electrical motor leading to: better process control, less wear in the mechanical equipment, less acoustic noise and, significant energy savings. Harmonics in Variable Speed Drive Systems: Variable...
Read MorePower Factor Correction
Power Factor Correction? Most loads employed in industry such as induction motors, transformers, light ballasts and induction heating furnaces are predominantly inductive. Such loads draw two kinds of power: Active power (kW) to perform work Reactive power (kVAr) to build the magnetic field. The active and reactive power make up the total power – apparent power measured in kVA. Reactive power is considered as wasted energy as it does not contribute to useful work. The relationship between the three power quantities can be explained using the power triangle as shown in Figure 1. The...
Read MorePower Quality Audits
Power Quality Audit A power quality audit consists of the inspection of an electrical system to ensure its reliable, efficient and safe operation. Network and power quality analysers are used to detect and record any disturbances in the electrical installation. Typical problems that can be detected are voltage drop and flicker, low power factor, harmonic distortion, voltage transients and imbalance in an electrical system. Failing to timely address any of these disturbances might lead to tripping, reduced lifetime or damaged equipment. Following a power quality audit, our clients will...
Read MoreEnergy Audits
Energy Audit An energy audit is an exercise that is carried out to give our clients a thorough picture of where energy is being used and/or lost. We provide this service to domestic, commercial and industrial premises. Our team will evaluate the building facility, the energy bills, lighting and equipment and the operating hours. In commercial and industrial facilities a detailed energy audit is normally recommended. This entails monitoring and recording of energy data. At the end of an energy audit, our clients will be presented with a report of the findings and any analysis that was...
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