Month: October 2017

General Electric Multilins 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 […]

Transformer Oil Samples

Transformer oil – what is it?   Transformer oil is an oil that is stable at high temperatures and has excellent electrical insulating properties. Typical motor oil that most people think of, is not the type of oil in a transformer. Transformer oil keeps the transformer cool. It also insulates the transformer and allows electrical components to be […]

Electromechanical Relay – Contact Cleaning

Electromechanical Relay – Contact Cleaning   Equipment owners often wonder the importance of maintenance on any variety of equipment. Some owners would even say that electrical maintenance is a waste of money. I have a demonstration of an electromechanical relay with dirty contacts.   When watching the video, notice the contact below the coil begins […]