Vfd is shorted for variable frequency drive also known as ac drives and. As an example, ac 480v, 60hz supply is applied to the vfd which varies the signal voltage and frequency to have control of the speed. Therefore in order to control the motor speed it is necessary to control the frequency of the supply. Challenges and solutions of protecting variable speed drive motors angelo daversa, bob hughes, and subhash patel, schweitzer engineering laboratories, inc. These variable frequency drives vfds accurately control the speed of standard ac induction or synchronous motors. A variable frequency drives used in a drivesystem consisting of the following three mainsubsystems. The output of the motor drive is 3phase pulse width modulation pwm ranging in possible operation frequencies from 0hz to khz. Ac motor, main drive controller assembly, and drive operator interface. Drive type and motor control algorithm will effect how a vfd trips on opl acs550 only trips in vector mode vfd faults. Understanding variable frequency drives learn about the various types of vfds, and what their purpose and advantages are. Mar 31, 20 a variable frequency drives used in a drivesystem consisting of the following three mainsubsystems. Variable frequency drives ressources naturelles canada. Variable frequency drive vfd usage has increased dramatically in hvac applications.
Also covered are issues related to vfds, some solutions to vfd issues, and how vfds can. Variable frequency drive vfd can be used in lots of fields. This manual is intended to help users of variable speed drives successfully install. Variable frequency drives vfds popular speed control devices used in industrial, commercial and residential applications. A variable frequency drive is a device used in a drive system consisting of the following three main subsystems. Any variable frequency drive or vfd incorporates following three stages for controlling a three phase induction motor rectifier stage. Some types of singlephase motors or synchronous motors can be advantageous in some situations, but. The variablefrequency drive training system is a stateoftheart training system specifically designed to introduce students to the basic principles of variablefrequency drives vfds. This includes that many of the possibilities of the vector variable frequency drive cannot be discovered without additional automation tools to deliver feedback to the vector variable frequency drive. A better understanding of vfds will lead to improved application and selection of both equipment and hvac systems.
Ach550 low voltage ac drive hvac drive abb free bim. A sourcebook for industry i acknowledgments improving motor and drive system performance. Freq drive training variable speed drives explained. A variable frequency drive vfd is a type of motor controller that drives an electric motor by varying the frequency and voltage supplied to the electric motor. Dec 17, 2019 any variable frequency drive or vfd incorporates following three stages for controlling a three phase induction motor rectifier stage. Challenges and solutions of protecting variable speed. This paper describes the design processes for a 3phase variable frequency drive vfd as broken up into two stages. Theyre the only real source, of understanding how these amazing inventions work. Variable frequency drive is a technology where the rotational speed of an electric motor is controlled or varied electronically electric motors were invented in the early 1800s.
Its useful to choose a 4 quadrant variable frequency. It provides a comprehensive, highquality, and costeffective solution to rapidly build student knowledge in vfds and their motor applications. The most popular type is the 3phase, squirrelcage ac induction motor. A converter is a device to create the dc from the ac power supply. The drives section is in book 2 of current version of our catalog, or you can download pdf of section here. P configured enclosed p with preengineered cabinet options. Hitachis sj300 series variable frequency drive delivers full feature performance across a wider range of demanding applications requiring high starting torque and functional versatility.
Upreaddownload up to 9 parameter sets from units to opm and back. These first electric motors ran off of dc direct current because that was the only electricity available at the time. These variablefrequency drives vfds accurately control the speed of standard ac induction or synchronous motors. In two positions, the voltage is zero, ie, when all the phases are connected to the same dc bus, either negative or positive. Danfoss, abb, telemechanique, honeywelltrend, jaguar, hitachi, imo, control. Variable frequency drive types there are three different vfd design types presently on the market. It varies both the frequency and amps of the ac waveform being delivered to the motor saving money in electricity.
It is ideal for changing the speed of induction motors by changing the frequency. A variablefrequency drive is a device used in a drive system consisting of the following three main subsystems. The vfds are now commonly applied to air handlers, pumps, chillers and tower fans. When a variable frequency drive vfd is commissioned, following guidelines makes the difference between installations that run for years and those with much shorter life cycles. For more, please see the ieee standard dictionary of electrical and electronics terms1. Part of the electricians technical reference series, this field guide is ideal for gaining access to information about variable frequency drives, including how. In order to properly cover the subject, it will be broken into four distinct parts.
The ach550 is an adjustable frequency ac drive designed specifically for the hvac market. The vfdtrainer freq drive training software is a tutorial of the ac frequency drive and related motor control troubleshooting. This paper gives a list of the parameters that i looked at to make my selection about the needed vfd. See the basic principle with the singlephase ac as the simplest example. Install a variablespeed drive the right way processing. A vfd can have many different names but is most commonly referred to as a variable speed drive vsd, frequency converter or an inverter. Brief explaination about working of vfds, benefits and. Variable frequency drive, operation and application of variable. There are applications, in particular very large, highpower, lowspeed drives, where dc will be used for many years to come. A freq drive tutorial on variable frequency drive operation, installation, programming and troubleshooting. Department of energys does advanced manufacturing office amo with support from the copper development association cda. General guidelines apply to most drive brands, but reading the provided installation manual and documentation is important. However, some mechanical trains driven by vfd motor systems have. Principles of operation ac vfd drives natural resources.
Each part of a variable frequency drive has the following function. The most common centrifugal load applications that use vfds are pumps, fans, and compressors. Variable speed drives vsds, also called variable frequency drives, are a valuable tool for the energy manager. Dc motor operating characteristics are determined by the physical motor design i. The system may include transformers for high voltage system. The term inverter and variablefrequency drive are related and somewhat interchangeable. In theory, these vfds differ primarily in the type of rectification by which they convert ac power to dc power.
Variable frequency operation hence the speed of the motor depends on the applied frequency, as well as the winding arrangement, and a little on the load. Vfd drives were first introduced in 1983, and the insulated gate bipolar transistor has in the past 20 years become the standard for vfd drives as an inverter switching device. Dc drives are still prevalent in the drive industry, making up some 40% of the market. A sourcebook for industry glossary here are some of the principal terms associated with motor and drive systems. Before selecting a variable frequency drive vfd for an existing electric motor, its important to know the purpose and characteristics of the different components involved in the process. The variable frequency drive industry is growing rapidly, and it is now more important than ever for technicians and maintenance personnel to keep vfd installations running smoothly. Vfds and motor control training the electricity forum. Labvolt series by festo didactic variablefrequency drive. Variable frequency drive basics variable frequency drive.
Pdf induction motors and variable frequency drives vfds are widely used in. The output, shown in figure 226, consists of a series of shortduration. The drive also regulates the output voltage in proportion to the output frequency to provide a relatively constant ratio of voltage to frequency vhz, as required by the characteristics of the ac motor to produce adequate torque. A variable frequency drive will control the speed of doubling machine according to the load variation and thus reduces power consumption. Each variable frequency drive basics coursetraining student will receive a detailed vfd specification and check list to use to ensure that all their vfd issues are. Each participant will receive a dvd with dozens of articles and papers on vfd and motor data as well as the full coloured slide presentation for printing as required. The basic configuration of a variable frequency drive is as follows. Design strategy for a 3phase variable frequency drive vfd. The above figure shows how the voltage and frequency are varied by a variable frequency drive. After the power flows through the rectifiers it is stored on a dc bus. A variable frequency drive vfd is a type of controller that drives an electric motor by varying the frequency and voltage supplied to that electric motor. Pdf the vf curve used in vf drives simply explained. Parmenter, in energy management principles second edition, 2016.
By the 1980s, ac motor drive technology became reliable and inexpensive enough to compete with traditional dc motor control. An inverter, in general, is a device that converts dc power to ac power. It is designed for portability and powered using a standard. In variablespeed applications, a dc motor may be operating in one or more modes. Typically the vsd system consists of a threephase ac induction motor and a variable frequency power supply. Eaton offers a bestinclass portfolio of variable frequency drives vfds that are designed to meet your performance requirements while saving space, improving safety and working smarter. The variable frequency drive converts this line power into a pulsed output voltage that duplicates varying alternating current to a desired frequency speed. A variable frequency drive controls the speed of an ac motor by varying the frequency supplied to the motor. This collection of adjustable frequency drives is designed for variable torque applications like fans and centrifugal pumps.
Challenges and solutions of protecting variable speed drive. Adaptivebasic autotuning autotuning to perform sensorless vector control can. With vfds, speed control with full torque is achieved from 0 rpm through the maximum rated speed and, if. A variable frequency drive system generally consists of an ac motor mostly 3 phase induction motor, a controller solid state electronic power conversion devices like. This paper covers what a variable frequency drive vfd is, the different types of vfds, their functions, and their benefits. Contents introduction block diagram building blocks modes of operation vfd parameters some potential problems harmonics and thd recent improvements in the ffcl system. Huge energy savings potential operating centrifugal fans, pumps and compressors vary frequency of electrical. Ac motor, main drive controller assembly, and driveoperator interface 210211 ac motor. In some applications such as speed control for a conveyor, the. In this presentation, we will be covering variable frequency drives vfds and their theory, application, and troubleshooting. Aug 11, 2015 a variable frequency drive vfd is a type of controller that drives an electric motor by varying the frequency and voltage supplied to that electric motor. Variable frequency drives troubleshooting larry stanley, regional sales engineer, january 2014. There are a lot of tradeoffs in the different designs and depending on the goals and preferences of the.
Variable frequency drive vfd a vfd can be used to control both the speed and torque of a standard induction ac electric motor. As the frequency is decreased, the speed of the motor also decreases. Vfd performance has improved so much in the recent past, that dc drives are often replaced with ac machines that provide added benefits. The variable frequency drive is developed to control induction motors in an automated environment. What are some good vfd variable frequency drive books. The variable frequency drive training system is a stateoftheart training system specifically designed to introduce students to the basic principles of variable frequency drives vfds. An electronic drive for an ac motor controls the motors speed by varying the frequency of the power sent to the motor.
Energy savings with variable frequency drives the basics. Thirty years ago when we were first seeing 30 hp variable frequency drive vfd the size of a refrigerator and now the size of a brief case, and there was no such thing as a severe duty motor, and it was an absolute taboo to use a variable frequency drive vfd for variable speed. The most common type of packaged vf drive is the constantvoltage type, using pulse width modulation to control both the frequency and effective voltage applied to the motor load. Variable frequency drives are widely used nowadays in all industrial and domestic applications. Variable frequency drives applied to ac motors are by far the most common. Other names for a vfd are variable speed drive, adjustable speed drive, adjustable frequency drive, ac drive, microdrive, and inverter. Built in as standard are an extensive library of preprogrammed hvac application macros that, at the touch of a button, allow rapid configuration of inputs, outputs and parameters for. P bypass enclosed p with preengineered bypass motor control and cabinet options. Variable frequency drives are typically 9298% efficient with 28% losses being due to additional heat dissipation caused by the high frequency electrical switching and the additional power required by the electronic components. If the frequency is reduced, the voltage must be reduced or the magnetic flux will.