MV system coordination doesn't have to be complicated, as long as you know the types of protective relays available, their function, and how they work.Recently, solid-state electronic relays, just like the solid-state trip unit shown at the right...
If you design or install large equipment layouts, you need to watch out for special rules covering access to the required workspaces. Don't get confused between the rules covering workspace sizing, and the other rules we address in this article on...
AT A GLANCE: AC power generation is no longer the exclusive domain of utilities. Many contractors and non-utility maintenance people now have responsibility for generator systems. Suppose you see fluctuations in frequency, voltage, kW, or kvar. Do...
What does the NEC actually require in the way of overcurrent protection for conductors supplied by a generator?One of the more confusing areas of the Code involves the what, where, and when of overcurrent protective devices protecting conductors...
Why do these devices, a though generally reliable, sometimes fail unexpectedly?Since their introduction in the late 1950s, solid-state contactors and starters have taken over many functions that traditional electromechanical devices (EMDs) either...
Q We recently had a problem providing temporary power to numerous pieces of 208V, single-phase equipment of various sizes. Sources of power were a number of 120/208V panels, having different power/current ratings. Some panels were unloaded, some...
Here's how to select and install resistance heaters for reliable operation of motors in damp locations.You can avoid condensation problems in motors by maintaining a winding temperature 5 [degrees] C to 10 [degrees] C above the surrounding air...
The complexities of modern loads, such as PWM power supplies, variable frequency drives, and other electronic equipment, place a whole new light on sizing generator sets.Engine-generator sets supply power to a very wide range of facilities - from...
Transformers, engine-generators, power supplies, and batteries are important components of power distribution systems, and their improved performance and reliability are key to facility operation.New technology has revolutionized generator sets...
Once thought to have outlived their usefulness, operational amplifiers are as popular today in control applications as they ever were.While many predicted the demise of operational amplifiers (op-amps) because of the development of digital...
