Every month, Control’s editors take a specific product area, collect all the latest, significant tools we can find, and present them here to make your job easier. If you know of any tools and resources we didn’t include, send them to [email protected], and we’ll add them to the website.
ADJUSTABLE-FREQUENCY DRIVES 101
Danfoss
815-639-8600
www.danfoss.com
This collection of lessons covers some of the basic information needed to understand the installation and operation of adjustable-frequency drives (AFDs) for the industrial market. The lessons cover the functions of AFDs, control arrangements for AFDs, AFD parts and theory, and application and power input terminology for AFDs. Each lesson begins with a self-test. If users successfully pass the self-test, they can skip the particular lesson and move on to the next one. At the end of each lesson, there is another self-test to ensure that the information has been properly assimilated. The direct link is at http://tinyurl.com/2b3gz4t.
BASIC MOTOR CONTROL
DocStoc
www.docstoc.com
This is an introduction to basic electric motor technology, including sections on starting and stopping motors, motor protection and operational control. Topics covered include manual and magnetic starters, overcurrent and overload protection, fuses and circuit breakers, NEC calculations, ambient temperature compensation and more. The material is free for download. The direct link is http://tinyurl.com/28hq4py
MOTOR AND DRIVES BASICS
PAControl.com
www.pacontrol.com
Here is a series of free, downloadable PDFs on motors and drives. The first is a general introduction to the subject, covering choosing the right motor/drive combination, AC induction motors, torque and horsepower, motor losses and loss reduction techniques, motor economics and more. Other PDFs cover motor basics, adjustable-speed drives and electric motor controls. The direct link is www.pacontrol.com/Motor1.html.
MOTOR MOVIES
Automation Direct
800-633-0405
www.automation.com.
This is a series of four short videos that cover the building of a combination manual motor starter. The page also contains links to information on how to wire a motor starter, motor control relays, and a motor control overview. The direct links is http://tinyurl.com/2ectz9v.
PROTECT AC MOTOR BEARINGS
Electro Static Technology
207/998-5140
www.est-aegis.com
Today, the challenge facing system designers and engineers is to minimize damage to AC motors from shaft current. From its first minute of operation, a VFD induces destructive voltages that build up on the motor shaft until they find discharge paths to the frame (ground). In most cases, the motor bearings present the path of least resistance. Once voltage is sufficient to overcome the resistance of the oil film layer in the bearing, the shaft current discharges, causing electrical discharge machining (EDM) pits and fusion craters in the race wall and ball bearings. “Preventing VFD/AC Drive-Induced Electric Damage to AC Motor Bearings” discusses measures to prevent this phenomenon. The direct link to this free PDF is located at http://est-aegis.com/TechPaper.pdf.
ALL ABOUT DC MOTORS
Micro-Drives
800/807-9166
www.micro-drives.com
These web pages offer an overview of DC motor technology. Tutorials include selecting a DC motor, calculations, including mechanical requirements, torque-speed curves and numerical and thermal calculations, development of electromotive force and Faraday’s Law. The website has additional information on brushless DC motors, gearheads and encoders. The direct link is at http://tinyurl.com/2dasnfo.
FUNDAMENTALS OF MOTION CONTROL
National Instruments
800/531-5066
www.ni.com
Part of the National Instruments Measurement Fundamentals series, this tutorial covers the fundamentals of motion control systems, including software, motion controllers, drives, motors, feedback devices and I/O. Also covered are components of a motion control system, software for configuration, prototyping, development, motion controllers, move types, motor amplifiers and drives, motors and mechanical elements and feedback devices and motion I/O. The direct link is at http://tinyurl.com/yefce37.
