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...
MV power cables are perceived as commodities, but are all makes alike?Shielded, 90 [degrees] C (Type MV-90), medium-voltage(MV) power cane (5kV to 35kV) has long been considered a commodity product, with little differentiation seen between...
Reduced starting currents don't justify derated controllers, but different motor time ratings may affect required horsepower ratings.An elevator service firm reported that it was seeing motor starters for some of the elevators it was working on...
The complaintThe essence of the complaint was that the wrong Technical Committee has been given jurisdiction over the material in Section 6-2 of the Fire Pump Standard. The complaint asked that when the Council issued the new edition of NFPA 20 ...
