It was late in 2017 when the notice for the Second Draft meeting for the 2019 edition of NFPA 70B, Recommended Practice for Electrical Equipment Maintenance came out, and within the agenda was an item to discuss the 2023 edition. COVID-19 wasn’t even a thought for any of us. Social distancing, masking up, and quarantine were unheard of, and Teams/Zoom …
How hot is too hot? Motors and transformers have maximum operating conditions, but can I exceed those ratings on occasion and not damage the equipment? In my years as an electrical insulation application consultant, the most common questions posed by end users regard insulation thermal classes and what effect they have on machinery reliability and life expectancy. Many articles have …
The stator core of a rotating machine is composed of multiple stacked layers to minimize eddy current losses. A short between two or more layers leads to higher local eddy currents. This in turn can lead to local hot spots, which in a worst-case scenario can cause a partial core melt and eventually damage the machine. A ring flux (or …
Measuring the winding resistance of generators and motors is one of the essential tests used in factory acceptance testing and during periodic routine testing procedures. This test can detect various problems in rotating machine windings, including a turn-to-turn short circuit in windings, which reduces a motor/generator’s ability to produce a balanced magnetic field, and a phase-to-phase short circuit, which in …
Imagine this: A new hyper-scale data center is built in rural New Jersey. It has more than 100 25 KV cables. Six months into operation, a cable termination fails catastrophically, and the forensic investigation determines that termination workmanship was lacking. Partial discharge caused tracking, and the cable flashed over. But that’s not the nightmare scenario. The nightmare scenario is that the …
Hydro-Quebec (HQ) is a major Canadian utility that manages the generation, transmission, and distribution of electricity to more than 3.8 million customers. Its distribution network includes over 12,000 km (7,456 miles) of medium-voltage underground distribution cables and more than 600,000 accessories — each with potential for failure. Medium-voltage (MV) underground cable systems are a critical part of the distribution network …
As time progresses and a cable system ages, the system’s bulk dielectric strength degrades. During this aging process, artifacts such as water trees, delamination, voids, and shield corrosion raise the local stress placed on the cable during normal operation. The exact way in which the strength of a device degrades will depend upon many factors including voltage, thermal stresses, maintenance …
America has been built on progress. Author C.S. Lewis once stated: “We all want progress, but if you’re on the wrong road, progress means doing an about-turn and walking back to the right road; in that case, the man who turns back soonest is the most progressive.” It could certainly be contended that the man who never has to turn …
The world is transitioning to electric vehicles (EVs). In order to do so, thousands of charging stations are needed. As with any emerging technology, a lot of new terminology and new processes must be learned. This article aims to simplify the world of EV charging with a deep dive into the terminology, statistics, and installation process for electric vehicle (EV) …
“People who are trying to change the world need to use checklists.” BUSINESSMAN AND AUTHOR GUY KAWASAKI Checklists and effective job briefings are important to ensure hazards that may exist when performing a task are addressed before starting the job. In addition, job briefings are important to ensure people understand their job roles and have a chance to speak up …