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Some First-Generation Protective Relays from Silent Sentinels 1924

Silent Sentinels 1924 Excerpt #7 This excerpt from the 1924 version of Silent Sentinels lists some of the protective relays available in 1924. This is the 7th in the series. Follow these links to learn

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Calculation of Short-Circuit Current from Silent Sentinels 1924

Silent Sentinels 1924 Excerpt #6 This excerpt from the 1924 version of Silent Sentinels discusses how electrical engineers calculated short-circuit currents operated in 1924. This is the 6th in the

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Valence will be at the NETA PowerTest 2015 Conference in Nashville, TN

The NETA PowerTest Conference is one of the best conferences in the industry. It starts on Monday, March 2nd with a series of 45 minute lectures from industry experts. There are several tracks, or themes,

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Please Explain the Principle of Weak InFeed Echo Permissive Over Reach Transfer Trip Schemes?

Rahim submitted this question to the Ask Chris section of the RelayTraining.com website. Most line distance protection schemes assume that the system will always be able to supply enough amps to make the

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Methods of Clearing Ground Faults from Silent Sentinels 1924

Silent Sentinels 1924 Excerpt #5 This excerpt from the 1924 version of Silent Sentinels discusses how electrical engineers understood how alternating-current systems (AC) operated in 1924. This is the

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When I test induction disc relay type … Is the pickup value the value at which the disc starts rotating?

This question was submitted via the Ask Chris form where you can ask me relay testing questions that I can hopefully answer. Creating test plans for digital relays is often difficult because you can have

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Methods of Clearing Short Circuits from Silent Sentinels 1924

Silent Sentinels 1924 Excerpt #4 This excerpt from the 1924 version of Silent Sentinels discusses how electrical engineers understood how alternating-current systems (AC) operated in 1924. This is the

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Alternating-Current Systems from Silent Sentinels 1924

Silent Sentinels 1924 Excerpt #3 This excerpt from the 1924 version of Silent Sentinels discusses how electrical engineers understood how alternating-current systems (AC) operated in 1924. This is the

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Methods of Applying Relays to Circuit-Breakers from Silent Sentinels 1924

Silent Sentinels 1924 Excerpt #2 This excerpt from the 1924 version of Silent Sentinels discusses how electrical engineers were applying relays to circuit-breakers in 1924.  This is the 2nd in the series.

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Possibly the First Protective Relay Book – Silent Sentinels 1924?

I remember randomly picking up an excellent protective relay book off a relay technician’s bookshelf when I first started relay testing in the 1990s. The book was old (written in the age of electro-mechanical

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Testing Directional Overcurrent Relays

In the previous post about Directional Overcurrent relay (67) testing (Finding the Direction in Directional Overcurrent Relays), we reviewed Directional Overcurrent protection from a system perspective

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Ask Chris: What is the difference between contactors, motor starters, relays and circuit breakers?

A reader submitted a question through the Ask Chris form. I’ve expanded the original question from “what are the differences between relays, contactors and motor starters?” to “What

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Finding the Direction in Directional Overcurrent Relays

A reader recently asked a question about the forward and reverse directions described in the Directional Overcurrent Relay section of The Relay Testing Handbook series.  I used electro-mechanical directional

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A Good Resource for Electrical Theory Basics

All high voltage electrical testers should understand the basics of electrical theory. Unfortunately, Many people in the high voltage electrical testing industry fall into testing by accident and never

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Potential Transformer Testing (PT/VT)

I co-wrote an article for the NETA World magazine in 2004/2005 that covers several different manual techniques for potential transformer testing that explains several low-tech solutions for potential transformer

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