So, whilst the rapid introduction of new technology and variable frequency drives is a key factor in the success of manufacturers of vfds, it also creates the conditions for fierce competition as manufacturers compete and need to survive in a marketplace that demands a customized variable frequency drive delivered at the cost and speed of a. The speed of a motor defines its rate of converting energy, whilst the torque is a measure of the turning force on an object such as a flywheel. Vfds may be referred to by a variety of other names, such as variable speed drives, adjustable speed drives, or. Confirmation of dimensions and data will be supplied on reuest. Integrated power electronics then inverts the dc supply into a simulated pwm sinusoidal output with continuously variable. For fixed center drives, do not start until a torque arm bracket is installed. Speed drive vsd adjusts the pump rate to match the wells conditions on every stroke, based upon the previous stroke. In the most typical installation, a belt connects a variable speed pulley to a driven sheave. It includes an introduction to drives, which may be informative to first time users. Two physical quantities describe the state of the shaft. Motor data ratings are referred to as the power of the motor in kw and the full load current flc.
Variable speed drives an overview sciencedirect topics. Variable speed drives are also used to control pumps on variable flow pumping systems and to control refrigeration compressors in centrifugal chillers. Mar 31, 20 a variable frequency drives used in a drivesystem consisting of the following three mainsubsystems. Variable speed drives trend variable speed drives 0. The combination of a constant speed motor and a continuously adjustable mechanical speed changing device might also be called an adjustable speed drive. Where process conditions demand adjustment of flow from a pump or fan, varying the speed of the drive may save energy compared with. Variable frequency drives vfd, aka variable speed drive vsd have been available for use with a wide range of applications for over 20 years. Motor ramping up in speed or only when approaching full speed. Determine speed range required for your machine processes. There are three major vfd designs commonly used today.
With vfd speed control on a centrifugal fan or pump motor, energy use follows the affinity laws, which state that the motor electricity demand is a cubic relationship to speed under ideal conditions. These motors are used in most heating, ventilation and airconditioning hvac systems and account for a. Designed for robustness and compatibility with the control system architectures of your machines. Variable speed drives fitted with a voith geared variable speed coupling are compact, efficient and offer unbeatable reliability. If you have access to the vfd keypad confirm that it is showing the proper status run and speed command. Where n s is the synchronous speed, f is the line frequency, and p is the number of poles found as. A vfd is capable of adjusting both the speed and torque of an induction motor. These applications include single motor driven pumps, fans and compressors, as well as highly sophisticated multidrive machines. This manual is intended to help users of variable speed drives successfully install and utilise siemens standard drives.
Download practical variable speed drives and power. Advanced information is shown in italics, and may be skipped on first reading. Configuring energy optimizer function with drivetune. A variable frequency drive vfd, also known as ac variable speed drive, ac variable frequency drive, vfd inverter or variable voltage variable frequency drive, is a type of motor controller that drives an electric motor by varying the frequency and voltage of its power supply.
Variable speed drives altivar 61 and altivar 61 plus for asynchronous motors from 0. Drives there are a number of different terms used to describe the ac drive. This paper discusses variable voltage drives in lift systems, analyses the basic building blocks of these drives and discusses some of the technical points surrounding the use of thyristors in. The purpose of using these scrs in dc drives is to convert the fixed ac supply to variable dc supply that controls the motor speed. Then comes the variable speed drive applying a vsd to these applications is a good way to save energy. Typically the vsd system consists of a threephase ac induction motor and a variable frequency power supply. Dec 10, 2018 variable frequency drives vfds are electronic power controllers that allow for precise control of the speed of alternating current ac induction motors that drive a variety of rotating machines including fans, pumps and compressors.
Huge energy savings potential operating centrifugal fans, pumps and compressors vary frequency of electrical. Boosting productivity with the help of variable speed drives. Ac induction motors drive a variety of rotating machines including fans, pumps and compressors and find application in most heating, ventilation and. For example, an scurve pattern can be applied to a conveyor application for smoother deceleration and acceleration control, which reduces the backlash that can occur when a conveyor is accelerating or decelerating. The coated hub with its fourside polygon profile together. Low voltage drives with high power ratings, 90 to 2400 kw. A vfd converts the 5060hz fixedfrequency and fixedvoltage ac power supply into a dc supply, using an integrated rectifier. The first variable speed drives were certainly mechanical and were based on adjustable pitch diameter pulleys. Vfds function to adjust motor speed to better fulfill the requirements. Variable speed drives can also run a motor in specialized patterns to further minimize mechanical and electrical stress. Variable speed drives vsds, also called variable frequency drives, are a valuable tool for the energy manager. The speed of the rotating magnetic field can be determined as.
How to save energy with vfds variable frequency drives. In variablespeed applications, a dc motor may be operating in one or more modes. Until the advent ofthe ac variable frequency drive in the late 1950s,mechanical devices remained the predominant way to control the speed ofthe motor. An adjustable speed drive asd includes all devices that vary the speed of a rotating load, including those that vary the motor speed and linkage devices that allow constant motor speed while varying the load speed. The variable speed drive vsd is a highly sophisticated switchboardmotor controller. For variable speed drives, variable speed pulley rim speeds must never exceed 10,500 feet per minute. Use of motor protection circuit breakers with variable. A technology that controls a motors speed to correspond with its. Important user information solidstate equipment has operational characteristics differing from those of electromechanical equipment. Be sure to consider the type of machine and apply the proper service factor. Add to that the difficulty in evaluating efficiency and power factor and the.
Control method there are three basic methods to control a variable frequency drive. Variable speed belt drives achieve the versatility needed to maximize application efficiency and productivity while remaining an inexpensive solution. Changing any one of the variables will affect the other variables. Variable speed drives and soft starters schneider electric.
Variable speed drives change this frequency to change the speed of the motor. Energy is supplied to the process through the motor shaft. Many types of variable speed drives have been used over the years, starting with dc drives used primarily in industrial applications, and mechanical drives that varied sheave diameter. Power is the variable frequency drive of speed and torque and is a measure of the rate at which energy is used. Variable speed drive often uses less energy than an alternative fixed speed mode of operation.
Drivepm drive parameter manager is a pc tool for creating and editing parameter sets of variable speed drives to be suitable for flashdrop unit. However, only about five percent of motordriven applications use a variable speed drive to regulate and control the speed or torque, the rest use fixed speed motors. Drives are rated for constant torque and variable horsepower throughout the speed range. Typically, you can save 2050% of energy when using fans and pumps with variable speed drive. Vfd control also has the capacity to control rampup and rampdown of the motor during start or stop. This has given rise to substantial confusion by users and specifiers of variable speed drive equipment. The variable frequency drive evaluation protocol presented here. The benefits of variable speed drives applications in the car wash a common setup to control dryer motors is with acrosstheline starters to bring them up to full speed as quickly as the motor would allow.
The pulley is mounted on a motor shaft and the motor is at constant speed. Nov 12, 2018 variable speed drives vsds are electronic power controllers that allow for precise control of the speed and torque of alternating current ac induction motors that typically run at fixed speeds. Aka vfd, vsd, asd, drive, inverter, converter, etc. This level of ease and control provides customers with peak production while reducing their maintenance and overall operating costs. The actual output speed of the rotor is related to the synchronous speed via the slip, or percent slip. Understanding variable speed drives part 1 operating a motor at the outer limits of its voltage requirements reduces its efficiency and causes premature failure. The benefits of variable speed drives aerodry systems. Most motors are designed to operate at a constant speed and provide a constant output. A variable speed drive vsd, also known as a frequency converter, adjustable speed drive or inverter, is an electronic device that controls the characteristics of a motors electrical supply. Abstract variable speed drive technology has advanced dramatically in the last 10 years with the advent of new power devices and magnetic materials. Lenze product key variable speed drives with gearboxes product group gearbox gearbox family input design disco size 02c compact unit size 10b motor frame size 07112. Special attention has been given to electrical vsds and especially to ac drives. This method of starting creates large amounts of inrush currents, as high as six times the running.
Variable speed drives for food and beverage production english mp4 movie abb acs480 and acs580 general purpose drives. Most vfd drives for dummies integrate a solid state electronics controller consisting of a bridge rectifier, a converter, and an inverter module. Driveconfig the driveconfig kit is a new drive configuration tool for abb component drives, acs55, offering fast and safe configuration of unpowered drives. To understand the answer to this question we have to understand that the basic function of a variable speed drive vsd is to control the flow of energy from the mains to the process. Use of motor protection circuit breakers with variable frequency drives introduction a motor branch circuit, including a variable frequency drive vfd and one or more motor protection circuit breakers mpcbs, is a complex system and its performance depends on all co mponents, devices, configuration and their interconnection. Variable frequency drives troubleshooting larry stanley, regional sales engineer, january 2014 month dd, yyyy. Hydraulic variable speed drives have fairly specific uses, for example, in the automatic transmission system of motor cars. A vfd therefore provides continuous range process speed control as compared to the discrete speed control that gearboxes or multi speed motors provide. Adjustable speed drive asd, also known as variable speed drive vsd, describes equipment used to control the speed of machinery.
The zeromax drive speed range of 0400 rpm is given assuming an input speed of 1800 rpm and full load on the output shaft. The vfd is by far the most common type of asd hardware. The main purpose for all ac drives is to control the operation of the ac motor with regard to speed and torque. The book provides a basic understanding of the installation, operation and troubleshooting of variable speed drives vsds and also includes practical coverage of key topics such as troubleshooting, control wires, operating patterns, brake types, automatic restart, emc emi compatibility problems, basic reading for electrical engineers and those using vsd for. While all variable frequency drives vfds control the speed of an ac induction motor by varying the motors supplied voltage and frequency of power, they all do not use the same designs in doing so.
Vsds variable speed drives and their purpose therma. It varies the capacity of the esp by varying the motor speed, protects downhole components from power transients, and provides softstart capability. Elta fans limited has a policy of continuous product development and improvement and therefore reserves the right to supply products which may differ from those illustrated and described in this publication. As discussed earlier, some scr dc drives are supplied from single phase ac supply and use four scrs in the form of bridge for the dc rectification. Afd, vsd, vfd and inverters all are used but have the same meaning. There are many different designs including hydrostatic drives, hydrodynamic drives and hydroviscous drives. A variable speed drive vsd is a device that regulates. Three basic types of variable frequency drives offer certain advantages as well as disadvantages depending on your motor application. Variable speed drives altivar 12 schneider electric. Variable speed drives in lift systems article pdf available in elevator world 499. Variable frequency drives vfds popular speed control devices used in industrial, commercial and residential applications.
These applications include single motor driven pumps, fans and compressors, as well as highly sophisticated multi drive machines. But, early ac variable frequency drives vfd were bulky unreliable in critical applications and very expensive compared to the alternatives at the time. Power electronics based variable frequency drives are rapidly making older technology redundant. High resolution english mp4 movie 7 technical guide, dimensioning of a drive system english pdf technical publication. Many industrial processes such as assembly lines must operate at different speeds for different products. Companion pulley speeds beyond the ratings contained in this catalog are not recommended. Catalogues altivar 12 variable speed drives altivar 312 variable speed drives altivar 212 variable speed drives page 116 altivar 71 variable speed drives 1 heating, ventilation and air conditioning 2 the type of cooling depends on the model. Such systems are still in use but for obvious reasons are not in general use in industrial applications today. There are four basic types of electrically adjustable speed drives being installed in todays modern industrial machines. If the vfd system has bypass, there will be an overload device for the bypass circuit, but if tripped, will also prevent the vfd connect to the motor. Variable frequency drive basics theory variable speed drives.