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Monthly Archive for: «October, 2012»

Application of 4-pole Switchgear Devices

The majority of low-voltage switchgear is equipped with three contacts in the main circuit, which switch three-phase loads in all poles. In some applications switchgear with four main poles is… Read more

Oct 31, 2012 | Edvard

Application of 4-pole Switchgear Devices

Transformers Are Never Silent

Yes, we all know that transformers are never silent. This is actually quite impossible, but in an environmentally aware, highly regulated world, the issue is not the level of noise,… Read more

Oct 29, 2012 | Edvard

A three-phase oil transformer 225 MVA, 275 kV

Corrosion Types Encountered With Power Cables

Introduction Anodic Corrosion (Stray DC Currents) Cathodic Corrosion Galvanic Corrosion Chemical Corrosion AC Corrosion Local Cell Corrosion Other Forms of Corrosion There are numerous types of corrosion, but the ones… Read more

Oct 25, 2012 | Edvard

Corosion Types Encountered With Power Cables

Safety Clearance Recommendations for Transformer

Clearance from Outdoor Liquid Insulated Transformers to Buildings (NEC) Clearance between Two Outdoor Liquid Insulated Transformers (NEC) Dry Type Transformer in Indoor Installation (NES 420.21) Dry Type Transformer in Outdoor… Read more

Oct 24, 2012 | jiguparmar

Safety Clearance Recommendations for Transformer

The Good, The Bad and The Ugly Cable Insulation

The fundamental understanding of cable insulation properties forms the foundation for assessment of cable operability. These same fundamentals provide the basis for evaluating whether various electrical and physical tests and… Read more

Oct 23, 2012 | Edvard

The Good, The Bad and The Ugly Cable Insulation

Few Words About Three-Phase Alternator

The three-phase alternator, as the name implies, has three single-phase windings spaced such that the voltage induced in any one phase is displaced by 120º from the other two. A… Read more

Oct 20, 2012 | Edvard

Few Words About Three-Phase Alternator

Testing and Commissioning of Current Transformer

1. Objective 2. Test Equipment Required 3. Test procedures Mechanical Check and Visual Inspection Insulation Resistance Test Polarity Test Secondary/Loop Resistance Test Burden Test (optional test) Magnetization Curve Test (optional… Read more

Oct 19, 2012 | Edvard

Testing and Commissioning of Current Transformer

Definitions of Voltage Transformer Parameters

Rated voltage factor Rated primary voltage (Up) Rated secondary voltage Accuracy power Accuracy class Voltage ratio error Phase or phase displacement error Rated thermal limiting output The voltage transformer must… Read more

Oct 18, 2012 | Edvard

Definitions of the Voltage Transformer Parameters

Simplify Downstream Installation with Cascading

Cascading provides circuit breakers placed downstream of a limiting circuit breaker with an enhanced breaking capacity. The limiting circuit breaker helps the circuit breaker placed downstream by limiting high short-circuit… Read more

Oct 16, 2012 | Edvard

Simplify Downstream Installation with Cascading

Heating of the Dry-type Transformer

Although transformers can be classified by core construction (shell or core type), the more functional types of standardized classifications are based on how the transformer is designed for its specific… Read more

Oct 15, 2012 | Edvard

Heating of the Dry-type Transformer


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