Turning The Tables On Shaft Voltage And Bearing Currents
Jun 1, 1998, By David W. Schlegel, Russel J. Kerkman, and Gary L. Skibinski
High bearing current concentrations can damage bearing raceways. This damage can degrade bearing performance and even shorten motor life....
Motor And Drive Compatibility: A Must
Jun 1, 1998, By Paul K. Lindhorst, Magnetek
You bought VFDs to improve operations and processes while saving energy. Yet, you're seeing many costs going up and motor failures doubling. What's happening? It's almost certain you have a mismatch between your drives and motors. However, such a mismatch doesn't have to be....
Reduced-Voltage Starters: Choosing The Best Type For Your Application
Jun 1, 1998, By Steven N. Hinman, P.E.
The power company requires reduced-voltage starting to limit its line voltage dip. What type of starter is best for various-sized motors ranging from 200 hp to 2000 hp? See how a comparison of autotransformer and solid-state technologies drives the decision process....
Through-Wiring with Recessed Fixtures
Jun 1, 1998, By Michael O'Boyle, Lightolier
You may be surprised at how many conductors can pass through many fixture wiring compartments without requiring identification for through-wiring suitability....
Backup Your Backup
Jun 1, 1998, By Paul E. Pritzker
Providing protection for critical loads without also providing UPS protection simply transfers the risk form one component of a system to another....
Maybe You Should Choose A Brushless DC Motor
May 1, 1998, Terry Auchstetter
Brushless DC motors offer definite advantages in certain applications. So, should you automatically choose a brushless DC? After all, you're familiar...
Design/Build Job Saves High-rise Owners Money
Apr 1, 1998, Joseph R. Knisley
When Cleveland Electric, Atlanta, was hired on a design/build basis as the installing contractor for the renovation project of the William Oliver Building,...
Design/Build: Hard Facts About Software
Apr 1, 1998, John Chaney and Mark Lamendola
Does the new era of design/build mea you need a massive library of software to stay competitive? Some people say yes. The truth? All you need is a handful...
Uninterruptible Power Supplies: Distributed vs Centralized?
Mar 1, 1998, Shawn Smith
If you base your answer to this question on a thorough analysis, you could avoid a major blunder as well as unplanned equipment downtime.Which is a better...
Protecting Generators From Overload
Feb 1, 1998, Lawrence Bey
Pay close attention to how you size overload protection for generators. Now there's new technology that lets you better coordinate that protection with...
Clearing The Mystery Of Protective Relays
Jan 1, 1998, John A. DeDad
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,...
Using Interlocked-Breakers For Maintainable Automatic Power Transfer
Jan 1, 1998, James D. Martin
Space limitations forced a design-build company to use a novel approach to critical load transfer without interruption. Continuous facility operation...
When Is A Circuit Breaker Not A Circuit Breaker?
Jan 1, 1998, John W. Young and Ray Clark
Not all resettable overcurrent protective devices are circuit breakers; some are supplementary protectors. So how do you know one from the other?When...
Workspace Access For Large Equipment
Dec 1, 1997, Frederic P. Hartwell
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...
Prime Movers, Voltage Regulators, And Power Generation-Part 1
Nov 1, 1997, Woodrow "Chip" Saccoccio, P.E.
AT A GLANCE: AC power generation is no longer the exclusive domain of utilities. Many contractors and non-utility maintenance people now have responsibility...
Using overcurrent protection for generator conductors
Dec 1, 1996, Hartwell, Frederic P.
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...
Calculating temporary power from multiple panels for multiple loads.
Nov 1, 1996, Lawrie, Robert J.
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...
Power resources
Nov 1, 1996,
Transformers, engine-generators, power supplies, and batteries are important components of power distribution systems, and their improved performance...
Preventing condensation in 3-phase AC motors.
Nov 1, 1996, Ryan, Thomas J.
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...
Critical data for sizing gen-sets
Nov 1, 1996, Olson, Gary L.
The complexities of modern loads, such as PWM power supplies, variable frequency drives, and other electronic equipment, place a whole new light on sizing...
