March 2014

Electrical power system harmonic problems are mainly due to the substantial increase of non-linear loads due to the technological advances, such as the use of power electronic circuits and devices, in ac/dc transmission links or loads in the control of power systems using power electronics or microprocessor controllers. Such equipments create load-generated harmonics throughout the […]

There are so many Technical methods for the prevention and correction of voltage sag a few of them are described below. Tap Changing Transformers Saturable Reactor Regulators Static Voltage Regulator (SVR) Motorized Variacs Phase Controlled Regulators Electronic Voltage Regulators Soft Switching Line Conditioners Ferro resonant Transformers (CVT) Magnetic Synthesizers Flywheels and Motor-Generator (M-G) Sets Uninterruptible

Power Quality Management plays an important role in improving power quality. The fundamental goal of energy management is to produce goods and provide services with the least cost and least environmental effect. The term energy management means many things to many people The objective of Energy Management is to achieve and maintain optimum energy procurement

VOLTAGE IMBALANCE: Voltage imbalance is regarded as any differences in the three phase voltage magnitudes and/or shift in the phase separation of the phases from 120 degrees.It is normally expressed as the negative phase sequence divided by the positive phase sequence,as a percentage, measured using line to line voltages. EFFECTS OF VOLTAGE IMBALANCE: The effects of

The following points are the difference between Induction and Synchronous motor.

Variously called intelligent motors, smart motors or integrated motors and drives, these units combine a three-phase electric motor and a pulse width modulated inverter drive in a single package. Some designs mount the drive components in what looks like an oversize conduit box. Other designs integrate the drive into a special housing made to blend

Direct current drives are easy to apply and technologically straight forward. They work by rectifying AC voltage from the power line to DC voltage, then feeding adjustable voltage to a DC motor. With permanent magnet. DC motors, only the armature voltage is controlled. The more voltage supplied, the faster the armature turns. With wound-field motors, voltage

Major maintenance, troubleshooting and repair of drives should be left to a qualified technician, following the drive manufacturer’s recommendations. However, routine maintenance can help prevent problems. Here are some tips: • Periodically check the drive for loose connections or any other unusual physical conditions such as corrosion. • Vacuum or brush heat sink areas regularly.

As PWM AC drives have continued to increase in popularity, drives manufacturers have spent considerable research and development effort to build in programmable acceleration and deceleration ramps, a variety of speed presets, diagnostic abilities, and other software features. Operator interfaces have also been improved with some drives incorporating “plain- English” readouts to aid set-up and

One drawback to pulse width modulated drives is their tendency to produce voltage spikes, which in some instances can damage the insulation systems used in electric motors. This tendency is increased in applications with long cable distances (more than 50 feet) between the motor and drive and with higher-voltage drives. In the worst cases, the