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Monthly Archive for: «November, 2012»

Arrangements of LV Utility Distribution Networks

In European countries the standard 3-phase 4-wire distribution voltage level is 230/400 V. Many countries are currently converting their LV systems to the latest IEC standard of 230/400 V nominal (IEC 60038)…. Read more

Nov 30, 2012 | Edvard

Arrangements of LV Utility Distribution Networks

The Purpose Of Transformer Gas Relay

The transformer gas relay is a protective device installed on the top of oil-filled transformers. It performs two functions. It detects the slow accumulation of gases, providing an alarm after a given amount… Read more

Nov 29, 2012 | Edvard

The Purpose Of Transformer Gas Relay

How to Predict Life Span of the Switchgear?

The life span of switchgear basically depends on the size of the load and the number of switching cycles. Instead of a time span, with electromechanical switchgear reference is usually made to… Read more

Nov 28, 2012 | Edvard

How to Predict Life Span of the Switchgear?

Inspection and Test Procedures for LV Cables

Visual and Mechanical Inspection Electrical Tests Test Values TABLE 100.12 – US Standard Fasteners – Bolt-Torque Values for Electrical Connections Compare cable data with drawings and specifications. Inspect exposed sections of cables… Read more

Nov 27, 2012 | Edvard

Inspection and Test Procedures for LV Cables

Surge Protection for Frequency Converters

In principle a frequency converter consists of a rectifier, a d.c. link converter, an inverter and of the control electronics (Figure 1 above). At the input of the inverter the single phase… Read more

Nov 26, 2012 | Edvard

Schematic diagram of a frequency converter

Purpose of Miniature Circuit Breakers (MCBs)

Miniature circuit breakers (MCB) are primarily designed to protect cables and lines against overload (thermal) and short-circuit (electromagnetic). They thus care for protecting this electrical equipment against excessive temperature rises and destruction in the… Read more

Nov 24, 2012 | Edvard

Using Miniature Circuit Breakers (MCB)

HV Instrument Current Transformers in T&D

Electrical measurements on a high-voltage transmission and distribution systems cannot be made practically or safely with direct contact to the power carrying conductors. Instead, the voltages and currents must be brought down… Read more

Nov 23, 2012 | Edvard

HV Instrument Current Transformers in Transmission and Distribution Systems

VLT Drives in Wastewater Treatment Plant Applications

The most common use of frequency converters is to drive sludge pumps, elevators, conveyers, aeration, chemical dosing, clarifiers, digesters, presses and centrifugal dewatering. In the beginning water is being pumped into the… Read more

Nov 22, 2012 | MarkoCvrkota

VLT Drives in Wastewater Treatment Plant Applications

Few Words About Frequency Converters

Since the late 1960’s, frequency converters have undergone extremely rapid changes, largely as a result of the development of microprocessor and semi-conductor technologies and their reduction in prices. However, the basic principles of frequency converters remains… Read more

Nov 21, 2012 | Edvard

Few Words About Frequency Converters

Wind power applications, Grid connected or not?

There are perhaps four distinct categories of wind power which should be discussed. These are: Small, non-grid connected Small, grid connected Large, non-grid connected Large, grid connected By small, we mean a… Read more

Nov 20, 2012 | Edvard

Wind power applications, Grid connected or not?
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