

In the Beginning 1973 was an extraordinary time in my life; my family and I moved to Atlanta and started our new adventure. A big part of that adventure was starting work at Patterson & Dewar Engineers, Inc., which turned out to be one of the most satisfying experiences in my life. In high school, I always wanted to be an electrical engineer. A neighbor who was an engineer and another friend who was a…
Relay Testing Background Nearly all complex relays installed today are microprocessor-based. Relays no longer use a disk and magnetic fields to determine the overload condition, instead they rely on complex circuitry, programming, and user input settings to protect the facility. Each relay manufacturer utilizes different programming interfaces and languages and offers varying levels of customization. The various functions utilize an input (current, power, voltage, frequency) with or without a directional element to trigger a user-defined pick-up….
Data center owners want their new facilities to be completed on time, on budget, and operating as intended. This doesn’t seem like a particularly difficult task – except it is. Ask most people involved in data center construction, and they can give you tales of woe about projects gone wrong. All construction follows a similar path to completion: the owner identifies the need and budgets for a new facility, hires a design engineer, and awards…
The NEC requires over current protective devices (OCPD) to protect cables from overheating and catching fire which is achieved using long-time (LT) breaker settings. The NEC also provides guidance on ground fault (GF) and ground fault delay (GFD) settings. Additional settings on OCPDs include long-time delay (LTD), short-time (SD), short-time delay (STD), and instantaneous (I), which can be adjusted and coordinated to protect personnel and equipment from dangerous fault currents. If the only goal was…
Fitness centers are busy at the start of each new year as people renew their commitments to health and fitness with the help of sophisticated electronic equipment such as treadmills, exercise bikes, and stair climbers. One such facility contacted us desperate for help with repeated electrical problems, including variable frequency drive (VFD) failures, fitness equipment control screens locking up and requiring frequent reboots, and physical damage to electronic components requiring replacement. Building managers frequently blame…