Variable frequency drives for offshore marine environments. Variable frequency drive basics the electricity forum. I have workshop to maintenance and repair the variable frequency drive, after repairing the vfd must be tested and loaded to full load to ensure that the repair done 100%. Variable frequency drivea a variablefrequency drive vfd is a type of adjustable b speed drive used in electromechanical drive systems to control ac motor speed and torque by varying motor input frequency and voltage.
Their engineers suggested installing variable frequency drives vfds on the wall fans of the newly installed air handler to maximize their energy savings. Individual vfd manufacturers should be contacted to determine each drives footprint. The acs 600 single and multidrive family includes drives from 3 hp to 4,000 hp and voltages from 230 to 690 v. 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. Advanced physicsoffailure models are incorporated into the drive to convert actual stressors e. Many utilities are now offering rebates for the installation of vfds or retrofitting existing equipment with variable frequency drives.
The new, patented, predictive maintenance models are built around a common framework where the amount of life consumed by each component is tracked by the drive. Therefore dc drives and dc motors are being replaced by vfds. Each part of a variable frequency drive has the following function. The variable frequency drive shall be a clean power voltage source, advanced pulsewidth modulated, space vector technology motor controller which utilizes the latest igbt technology and surface mount construction to afford efficient use of available space, prudent energy consumption. Vfds are used in commercial and industrial settings where the climate of a large space needs to be controlled. If this is not possible, a metal plate at least as large as the back of the drive may need to be firmly mounted to the back of the drive see tables below. In frequency control, the variable frequency drive inverter supplies a series of dc voltage pulses to the motor terminals at a high frequency typically to 0 hz. The crankshaft knowledge bank for more information on polyphase induction motors 15 vfd operation. But i cant access to dc bus circuit each time, because i test and repair a lot of brands that could be contain dc bus terminal and could not. Variable frequency drive or vfd is the way that enables controlling of the speed of induction motor by applying varying frequency of ac supply voltage.
Service bulletin, preventive maintenance checklist of. Variable frequency drive vfd installation instructions input ac power 1. Introduction some applications demands operation in a quadrant region where applied torque is in the opposite direction of rotation of induction motor. It is possible to program 3 time channels to get different functions on the drive. Vhz if you decrease frequency, volts must decrease also to achieve constant torque volts 60 hz vhz volts 30hz 480 8. Eaton s sc9000 encapsulated powerpole ep variable frequency drive, available up to 12000 hp, is an awardwinning mediumvoltage drive combining innovation and dependability to deliver power, control and energy efficiency in a compact footprint. By integrating some simple, logical steps into your preventive maintenance pm program, you can ensure your drives provide years of troublefree service. A variable frequency drive vfd is like a throttle on a car.
In addition to speed control, the application of vfds results in process. As the frequency is decreased, the speed of the motor also decreases. Ac motor, main drive controller assembly, and driveoperator interface 210211. May 31, 2001 second of two parts do you know how to maintain variable frequency drives vfds. Variable frequency drive a variable frequency drive vfd is a static unit mainly consisting of semiconductor devices. To avoid fault during operation it is always better to perform preventive maintenance of variable frequency drive as per manufacturer recommendations. A variable frequency drive actually controls two parameters. Therefore in order to control the motor speed it is necessary to control the frequency of the supply. Always call certified variable frequency drive integrators or experienced technicians to perform preventive maintenance vfd services to. Dec 15, 2015 the beauty of variable frequency drive vfd is that the maintenance is negligible if are well maintained. Optional pc drive configuration software which runs on windows operating system is available.
An inverter, in general, is a device that converts dc power to ac power. An electronic drive for an ac motor controls the motors speed by varying the frequency of the power sent to the motor. Introduction in the united states 50% of the total electrical energy generated is consumed by rotating equipment. There are three major vfd designs commonly used today. Variable frequency drive, 600v, frequency drive routine maintenance. Variable frequency drives hvac products siemens usa. Huge energy savings potential operating centrifugal fans, pumps and compressors vary frequency of electrical. Below is a list of questions that are common to our products and services. A real time clock and timer functions an optional battery is necessary. The total harmonic current distortion thdi of a variable frequency drive vfd depends on the pulse assys. A converter is a device to create the dc from the ac power supply.
Why buy a vfd mechanical, electrical, and fluid power adjustable speed drives are available that offer some of the aforementioned benefits. Regeneration in variable frequency drives and energy. On the invitation to bid, change the question cutoff date to january 25, 2019. Variable speed drive preventative maintenance can reduce maintenance costs by up to 30 %. 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. Based on demand, a vfd adjusts the speed of an hvac fan or pump motor, saving energy and prolonging equipment life. Variable speed drive faq frequently asked questions joliet technologies is dedicated to providing our customers and website visitors with quality information about our products and services. Mn04001004e october 2007 list of figures continued figure a6. If the frequency is reduced, the voltage must be reduced or the magnetic flux will. Dec 17, 2019 any variable frequency drive or vfd incorporates following three stages for controlling a three phase induction motor rectifier stage. This twoday handson variable frequency drives course introduces the student to the world of variable frequency drives and their applications in industrial plants and commercial buildings. Enclosure air filters for type 12 enclosures with cooling fans, replace the air filters, as necessary.
You can use it, for example, to control a valve with the io of the ac drive. The term variable frequency drive is somewhat misleading, as is another generic name for it inverter. The drive keypad features builtin wizards that get hvac equipment up and running quickly and accurately. Drives without a backplate must be mounted directly to a solid wall with no spacers between the drive and the wall. Increased efficiency and reliability through an electromechanical. For example, an electric submersible pump esp up to 1,750 horsepower could be fitted with a drive that occupies a footprint of only 66 inches wide by 42 inches deep. A variable frequency drive will control the speed of doubling machine according to the load variation and thus reduces power consumption. Mechanical speed control 24 3 principles of operation ac vfd drives 25 a. Basic variable frequency drive maintenance tips vfd. Students will learn how to improve vfd control and efficiency, troubleshoot and fix vfds, reduce equipment downtime, and eliminate chronic vfd problems. Implementing advanced predictive maintenance functions. Motor switch ride through during maintenance the motor disconnect switch can be opened and closed. January 9, 2019 invitation to bid bl01719 variable. Induction motor and variable frequency drive inspection.
Variable frequency drives adjust your motor speed to closely match your output requirements, typically resulting in energy savings of 10 to 50%. Variable frequency drive thdi variable speed drives. The above figure shows how the voltage and frequency are varied by a variable frequency drive. The ac electric motor used in a vfd system is usually a threephase induction motor. 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. A fullwave power diode based solidstate rectifier converts threephase 50 hz power from a standard 220, 440 or higher utility supply to either fixed or adjustable dc voltage. Circuit breakers feeding the vfds are recommended to be thermalmagnetic and fast acting. Variable frequency drives, regeneration, matrix converter, spwm, utility cost saving, regeneration power unit selection.
Variable frequency drive vfd a vfd can be used to control both the speed and torque of a standard induction ac electric motor. Abbs extensive experience in drive maintenance means that we can optimize the service intervals according to the needs of different components and systems within your drives. Installed drives are maintained according to detailed product specific schedules. Preventive maintenance vfd precision electric, inc.
Most of the true rms handheld multimeters in the market have high ac bandwidth and are able to capture all the unwanted high frequency switching components generated by the ac drive. Page 1 appendix page 2 page 3 about this manual page 4 startup quick guide page 5 table of contents page 6 page 7 page 8 approvals page 9 page 10 page 11 page 12 safety page caution page 14 grounding and earth fault protection page 15 electromagnetic compatibility emc page 16 page. Dc drives and motors dcs 500 and dcs 400 dc drives are available from 5 hp to 10,000 hp and voltages. Inspection form page 1 of 3 variable frequency drive, 600v. Other names for a vfd are variable speed drive, adjustable speed drive, adjustable frequency drive, ac drive, microdrive, and inverter. Because vfds improved process performance and reduced maintenance costs, they replaced motor generator sets and dc drives. We will have 23 different demo vfds for students to work with in class. As well as helpful information you can use to make well informed decisions regarding your drive needs. Maintenance clean equipment a must keep your vfd clean. Each variable frequency drive basics course training student will receive a detailed vfd specification and check list to use to ensure that all their vfd issues are addressed.
Preventive maintenance is all great for the variable frequency drive, cleaning with dry air, checking connections and tightening with correct torque wenchdriver, replacing fan and having spare. Do you know how to maintain variable frequency drives vfds. Basic variable frequency drive maintenance tips as we have seen, increasing pressure to improve financial performance is driving a change in the way end users approach control of production, engineering, operations, and maintenance across the manufacturing enterprise. Output frequency the vfd shall be capable of variable frequency, variable voltage output in the range 0 500hz and 0 supply voltage. A variable frequency drive and ac squirrel cage motor are cheaper than a comparable dc drive and dc motor and can give the same speed and torque characteristics. Table 1 recommended drives maintenance tasks and schedule powerflex 750series, 70, 700, 700s, dc 0 92 81 71 61 51 41 31 012321 4567811 s 01 r91 a e y.
Technical specification for variable frequency drives. Town of branford variable frequency drives preventive. Depending on the ac variable frequency drive manufacturer, the switching frequencies of an ac drive ranges from a few kilohertz to as high as 30 khz. The third and last case study is an example of how a motor coupled with a variable frequency drive vfd was monitored, and how its operation was corrected.
A variablefrequency drive is a device used in a drive system consisting of the following three main subsystems. Medium voltage variable frequency drives mv vfd eaton. A power drive system consists of the frequency converter, the motor and equipment. Regular inspect variable frequency drive to see if there is running anomalies or not, we have following methods. Contact your local utility or search vfd rebate or go to the dsire website, a comprehensive source of information on state, local, utility and federal incentives. Brief explaination about working of vfds, benefits and. The beauty of variable frequency drive vfd is that the maintenance is negligible if are well maintained. Anyone can safely and quickly commission the bt300 using default parameters that are optimized. Regular preventive maintenance actions allow to control maintenance costs and to optimize life time performance. So i need to couple two ac motor to make the vfd loaded. Our systems integration division can build custom drive panels as well. Make the following changes to the above referenced bid. Mediumvoltage variable frequency drives vfd are available in power ranges from 200 to 100,000 kw. See the basic principle with the singlephase ac as the simplest example.
Variable frequency drives vfds in the 3 800 horsepower range. By integrating some simple, logical steps into your preventative maintenance pm program, you can ensure that your drives provide many years of troublefree service. Variable frequency drive vfd installation instructions. For variable frequency drive in continuous operation, we take an external visual inspection for the vfd running state. Ach55001 users manual drive package after opening the package, check that the following items are included.
Frequency inverters for 3phase asynchronous motors from 0. Pacmotion variable frequency drives user manual instrumart. Tighten all nuts and bolts, all terminal blocks, cablewire connections. The basic configuration of a variable frequency drive is as follows. Variable speed drive often uses less energy than an alternative fixed speed mode of operation. In two positions, the voltage is zero, ie, when all the phases are connected to the same dc bus, either negative or positive. Faq variable speed drives frequently asked questions. Variable frequency drives vfds popular speed control devices used in industrial, commercial and residential applications.
Variable frequency drive vfd troubleshooting and maintenance. Without a vfd, an hvac fan or pump motor is either 100% on or 100% off. Instantaneous torque as a predictive maintenance tool for. Daily inspection must be performed to prevent any fault from occurring due to the adverse effects from the operating environment, such as temperature, humidity, dust, dirt and vibration, changes in the parts with time, service life, and other factors. The width of the pulses is varied so that the average voltage seen by the motor is a sine wave of a given frequency. Vfds up to 2,250 horsepower can occupy a footprint of 82 inches wide by 45 inches deep. Typically, you can save 2050% of energy when using fans and pumps with variable speed drive. High efficiency over a wide speed range, ease of installation, low maintenance and other factors have contributed to increased application of vfds. The term inverter and variablefrequency drive are related and somewhat interchangeable. Preventive maintenance checklist of industrial control and drive system equipment. By controlling the output ac frequency, it is possible to drive the motor at different speeds based on the requirements. Its easier than you might think, but its something you shouldnt take for granted.
When we carry out maintenance on your drives, we will take care of tasks predefined in product specific maintenance schedules. Easytouse and highly reliable bt300 variable frequency drives reduce the cost of installation and maintenance while maximizing energy savings. Mediumvoltage drives abbs highly reliable acs is available from 400 hp to 6,700 hp and voltages of 2. Preventive maintenance maintenance for drives abb drive. Maintenance manuals guide for capacitor reforming in acs50, acs55, acs150, acs310, acs350, acs355, acs550, ach550 and r1r4 ointsintboards 3afe68735190 english. Low voltage vfd preventive maintenance is best performed on a periodic schedule, typically once per year. Variable frequency drive for induction motor elprocus. On the invitation to bid, change the bid submittal to february 1, 2019.
Consists mainly of visual inspection, cleaning with dry compressed air, checking connections for correct torque and setting up a replacement schedule for. By integrating a preventive maintenance vfd program, you can ensure your drives provide minimal repair service while maximizing production. An area that represents significant opportunity is the use of vfds to start and control motors. 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. The variable frequency drive evaluation protocol presented here addresses evaluation issues for variable frequency drives vfds installed on commercial and industrial motordriven centrifugal fans and pumps for which torque varies with speed. Variable frequency drive maintenance due to power electronics technology and microelectronics technology rapid development, variable frequency drive reforms and upgrades speed also is faster, introduce new products, improve performance continuously, enrich and strengthen function constantly. It varies both the frequency and amps of the ac waveform being delivered to the motor saving money in electricity.
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