Publication Date: May, 2005
Discount Price: $24.50 (Cdn)
Discount Price: $20.50 (U.S.)
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VARIABLE FREQUENCY DRIVES HANDBOOK
Variable frequency drives are controllers that are solid state electronic power conversion devices. The usual design first converts AC input power to DC intermediate power using a rectifier bridge. The DC intermediate power is then converted to quasi-sinusoidal AC power using an inverter switching circuit. The rectifier is usually a three-phase diode bridge, but controlled rectifier circuits are also used. Since incoming power is converted to DC, many units will accept single-phase as well as three-phase input power (acting as a phase converter as well as a speed controller); however the unit must be derated when using single phase input as only part of the rectifier bridge is carrying the connected load.
As new types of semiconductor switches have been introduced, they have promptly been applied to inverter circuits at all voltage and current ratings for which suitable devices are available. Currently, insulated gate bipolar transistors (IGBTs) are used in most VFD inverter circuits.
Electric motors used with variable frequency drives are usually three-phase induction motors. Some types of single-phase motors can be used, but three-phase motors are usually preferred. Various types of synchronous motors offer advantages in some situations, but induction motors are suitable for most purposes and are generally the most economical choice. Motors that are designed for fixed-speed mains voltage operation are often used, but certain enhancements to the standard motor designs offer higher reliability and better VFD performance.
This technical handbook is an invaluable resource on the maintenance and usage of VFDs, their characteristics in commercial and industrial applications and the issues surrounding feeder cables and motors when applied to VFD systems.
CONTENT:
- Variable Frequency Drive Basics
- Frequently Asked Questions About Adjustable Speed Drives
- Harmonic Distortion Damages Equipment and Creates a Host of Other Problems
- How to PM VFDs
- Control Arrangements for an Adjustable Frequency Drive
- Isolating Electric Machine Windings for Field Testing
- Considerations for the Use of AC Induction Motors on Variable Frequency Controllers in High Performance Applications
- Basic Parts and Operation of an Adjustable Frequency Drive
- Applications for Motor Current Signature Analysis
- The Need for Industry Standards for AC Induction Motors Intended for Use with Adjustable Frequency Controllers
- 10 Benefits Adjustable Speed AC Drives Provide to Industrial Users
- AC Induction Motors as Part of Variable Speed Drive Systems
- The Case for Variable Frequency Drives as a Final Control Element
- Benefits of Variable Speed Drives
- Web-enabling Variable Frequency Drives
- Energy Efficiency: Variable Frequency Drives
- Dealing with Line Harmonics from PWM Variable Frequency Drives
- Understanding Variable Frequency Drives
- Variable-Frequency Drive
- Current Shield Technology for Clean Room Applications
- How to Maintain a VFD
- Also: Directory of Variable Frequency Drive Manufacturers and Suppliers
- -- 96 Pages
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