The power company, or you, decide you need to de-energize a circuit. You rack out and remove your trusted 1960’s vintage breakers, of course you are suited up in the proper level PPE (Personal Protective Equipment). You then dust off your vintage ground and test device and install it in the cubicle. Connect the motor […]
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The Importance of Acceptance Testing
Before we can begin to talk about “Acceptance Testing”, you may or may not understand the phrase. Acceptance Testing pertains to all new electrical components. These are either purchased from a distributor, or even a manufacturer, but have never been put into “service”, i.e. energized. When a building is being remodeled, or even rebuilt, a […]
What is the purpose of a Transformer Load Tap Changer?
Transformer Load Tap Changers Load Tap Changers (LTC’s) could also be known as a type of voltage regulator. In the Washington DC area, we typically see LTC’s at places of distribution. Your typical government building or privately owned buildings do not use LTC’s. You could even say that businesses that do not own the extra […]
Medium Voltage Cable / 15kV Terminations
Medium Voltage Cables Electrical wire is an integral part of our lifestyle. Whether you care to notice or not, copper/aluminum conductors are everywhere. They provide power to every business and home that wishes to be connected. Most of the time, people who aren’t in the electrical trade, tend to see overhead power lines. Those consist […]
Effects of Frozen Moisture in Oil Filled Equipment
Good Old, Quality H2O! Recently, the temperatures have been rather cold in the Washington DC area. We hit a week of temperatures below 20°F. Yes, I know; not very cold when compared to our northern states or Canada. But it still brought up some very good talking points. Do you test equipment below 0°C (32°F)? […]
Transformer Vectors
This was a topic brought up on the job and I figured I would address it in a very general post. This will not go too in depth but will help you understand how a vector is configured and possibly understand what you are dealing with on the job. What is a vector? A vector […]
Custom Voltage Test Box
Do you make your own test boxes? Test boxes can be made for a variety of reasons. They are typically home made boxes that help to make manipulating voltage a little more usable for a specific task. They are usually not sold by a manufacturer because the market or target audience is extremely small. There […]
Transformer Snubber Assembly
What is a Transformer Snubber? It is a set of capacitors, surge arresters, fuses, and resistors typically found on medium voltage dry type transformers. What are Snubbers designed for? The main application has been to reduce damage to transformers during energizing applications. Energizing medium voltage transformers produces transient voltages. These transient voltages are a cause […]
General Electric Multilin Protective Relaying
Multilins SR745 & SR750 Model Power Supply Issues: Recently, I have been tasked to perform some relay testing on multiple General Electric SR relay models. But in particular, the issues experienced have been with the original model SR745 (Transformer Protection Relay) and the SR750 (Feeder Protection Relay) models. Here are examples of the Original and […]