This is a significant advantage for starting certain loads, especially positive displacement pumps that have a residual load of pumped material within the pump. The eddycurrent drive or clutch is a slip device consisting of two rotating elements that are coupled by a magnetic field. After the motor has reached its target speed, its controller engages the eddy clutch. Table 1 indicates the efficiency range of a magnetically coupled eddycurrent drive when matched to a centrifugal load.
Eddy current drives instruction manual revised february 18, 2004 drive source international, inc. Owing to their precise design and high efficiency, these products are used for maintaining constant torque application for variable load. Eddy current drive is an electromechanical device, which operates on eddy current principle. In eddy current drive, speed is varied by varying the field of eddy current coupling. When switching to a vfd for a constant torque load, the motor and the drive may require being oversized by a factor of 150% to 200%. The medium of torque transmission is a controlled magnetic field, generated by a stationary. A variable speed eddy current drive has a driven member and an output member. Other articles where eddycurrent tachometer is discussed. The eddy current method is based on the principle of generating circular electrical currents eddy currents in a conductive material.
The output member is structured and arranged to be coupled to a load. Powermag has been the market leader in manufacturing and developing eddy current variable speed drives and eddy current dynamometers. How dynamatic technology works adjustable speed drive system. Eddycurrent clutches consist of a field, ta chometer, and eddycurrent control. When a conductor is placed in the changing magnetic field, the induced current in the conductor is termed as eddy currents.
Either one of the electromagnet or the armature is coupled to a motor shaft 31 so as to rotate therewith, while the other is coupled to a load portion 21. Used in various packaging and printing industries, the offered eddy current drive is developed in accord with the industry laid norms and regulations. Pdf pulsed eddy current nondestructive testing and. Induced electromotive force is produced in the coil when there is a change in the magnetic flux linked with that coil. This manual generally covers all model numbers beginning with the letters dcd, followed by a hyphen and a number between 2 and 225, and ending with a hyphen followed by a number between 4041 and 4181. There is no physical contact between input and output members which results in smooth response thereby eliminating shock.
Zetec is the industry leader for costeffective eddy current testing ect in complex applications. Eddycurrent drives can produce more torque at low speed than an induction motor and vfd. The drive transmits constant torque at variable speeds. They can be induced within nearby stationary conductors by a timevarying magnetic field created by an. The drive also has an armature and an electromagnet. Eddy current controls flexible and precise control options for all your adjustable speed drives and brakes. Variable frequency drivehas low internal power losses over the speed range.
The svr1ec system makes use of an external speed signal to provide for regulating clutch field current to maintain drive speed proportional to either a local or. The driven member is structured and arranged to be coupled to a motor shaft. Our product range includes eddy current drive placed in threephase squirrel cage induction motor. The speed is externally controlled and the operating efficiency of eddy current drive is around 80%. The eddy current separator is designed to operate with a minimum amount of ferrous material in the waste stream. Other industries pump drive dredger pump drives proportional speed drive of hard board corrugating machine drive of bread baking machines chemical fiber industry operation of fans pumps, blowers, ect coordinate drive of resin finishing machine, slusher, ect. Eddy current drives power 312014 we are a force to reckon with in offering a large range of eddy current drives which are preferred as they have traits such as need minimum maintenance, available in power range of 1hp to 120 hp with variety of applications and also find applications in speed or torque control operations. Variable frequency drives and dc drives operate by electronically altering the input power to control the speed of the motor. Is it costeffective to replace old eddycurrent drives.
Dynamatic motors adjusto spede at drives ces drives. An eddy current drive sometimes called a dynamatic drive, after one of the most common brand names consists of a fixed speed motor generally an induction motor and an eddy current clutch. This is the basis of eddy current testing, by monitoring the voltage across the coil in such an arrangement we can detect changes in the material of interest. Variable frequency drives and dc drives operate by electronically altering. Using a variable frequency drive in a pumping system.
Analytical model of the eddy current response of a drive. An eddy current drive controls speed by regulating a direct current dc excitation coil on a magnetic rotor, rotating concentrically with a steel drum, driven by the motor at full speed. I believe i have come up with a test bed chassis where i can test differentstrength magnets and different configurations of this unique drive system for model railroading. Eddy current drive or clutchuses magnetic coupling to transfer torque at different speeds. Note that cracks must interrupt the surface eddy current flow to be detected. Buckley pdf, 429 kb eddy current testing at level 2, international atomic energy agency, vienna, 2011 pdf 5. Eddy current variable speed drive systems modern pumping. Installation, operation and maintenance instructions. An eddy current drive can easily deliver all the torque available from its drive motor at any speed, including zero. Dynamatic eddy current drivesbrakes heco all systems go. Conventionally, eddy current drive is used for varying the speed of cane carriers in sugar plant. An eddy current drive, also known generically as a magnetic drive, eddy current clutch or magnetic clutch, is an electromechanical variable speed drive that. The eddy current response due to a drivereceive coil system inside two concentric conductive tubes has been determined semianalytically. An eddy current drive 711 has an electromagnet 15, 17 and an armature 19.
Leaders in eddy current drives eddy current dynamometers. Eddy current transmission drive kingstone model works. Eddy currents are named so because the current looks like eddies or whirlpools. Eddy current technique is an important electromagnetic non. This is achieved by the use of a coil connected to an alternating current generator driving an alternating magnetic field primary field. High quality eddy current testing solutions for complete inspections. Pdf of other automatic eddy current test systems inline, 100% zero defect, testing, and auditing ibg ndt systems designers and manufacturers of stateoftheart ndt eddy current testers, instruments, and automatic test systems for automotive, bearing and other metal components including fastener, forged and cast parts, hard metals. The eddycurrent drive or clutch is a slip device consisting of two rotating elements that.
The drive efficiency at each operating point is equal to 100% minus the percent losses. The minidrive is a small, lightweight, rotating eddy current probe drive. The primary elements of eddy current variable speed drive are an ac motor, an eddy current clutch, a tacho generator and a seperate small solidstate electronic. Pdf modeling of eddy current distribution in the sst1. If necessary, eriez drum, pulleys and belt magnets should be placed upstream to remove this material. Tech talk february 2011 eddy current drives holland industrial. The eddy current drive is built within a stationary frame of fabricated or cast steel, with a lower flange and shaft similar to that of a vertical motor. Dynamatic adjustable speed drives, brakes and controls. Eddy current drives, also known generically as magnetic drives, eddy current clutches or magnetic clutches are driven at constant speed by an ac motor and utilize a simple electromagnetic device to control torque and speed to the driven load. Helper drive for paper machine excavator drive driver of rewinder, cutter, ect.
Astm e3052 standard practice for examination of carbon steel welds using eddy current array. Eddy current separator application rev xe light duty material recovery facility mrf metals sorting 3 products. Like the pumps and electric motors that drive them, eddy current drives are rotating machines. The function of an eddy current clutch is to transmit a controlled torque from the induction motor,prime mover to the load driven machine. Fundamentals of eddy current testing download ebook pdf. This premier and trusted vertical directory contains manufacturers, distributors and service companies giving access to all their information available on the internet. As an example, consider replacing an eddy current drive with an ac adjustable frequency drive on a 350ton press with an existing 40 hp eddy current drive, 1800 rpm, 460v360 input, 50 fla, using a nema b, squirrel cage induction motor, 200 percent starting torque, and. The model considered the eddy current response by calculating the voltage induced in the receive voltage by a timeharmonic driving voltage, allowing for all the different coupling terms to be accounted for. Harsh environments such as asphalt and aggregate duty are no problem for the dependable and reliable performance of dynamatic dcd drives. Electricgenerator tachometers work by generating either an alternating or a direct current. The work of this section includes providing eddycurrent variable speed drive units with controls, couplings, accessories and spare parts. I wont bore with all the research and test platforms i built to get to this bench mark. Drive source international dsi is the worlds leading manufacturer of eddy current adjustable speed drives, brakes and controls. It is fan cooled tefc and has flanges and is mounted on eddy current clutch with a selfventilated common frame design.
The eddycurrent, or drag, type is widely used in automobile speedometers. The work of the following section applies to the work of. Replace eddy currents with ac drives to reduce maintenance. To determine which eddy current controller model can be used with your mechanical unit, please refer to the dynamatic controllers catalog section for the drive controller compatibility and selection chart. It has been designed to allow fast and accurate inspection of fastener holes in confined spaces. The motor can rotate at a continuous speed, while the speed of the load portion can vary by varying the energization of the electromagnet, so as to vary the. Energy savings example an eddycurrent drive on a standard efficiency motordriven 50. The armature is coupled to either the driven member or the output member, while the electromagnet is coupled to the. Eddy current controls adjustable speed drive controls. The primary elements of powermag eddy current variable speed drive are an ac motor, an eddy current clutch, a tacho generator and a seperate small solidstate electronic controller. Eddy current drive is a combination of a constant speed ac induction motor, coupled to an eddy current clutch. Rao nondestructive evaluation division metallurgy and materials group indira gandhi center for atomic research kalpakkam 603 102, tn, india email. Eddy current drive companies serving all industries. Eddy currents also called foucaults currents are loops of electrical current induced within conductors by a changing magnetic field in the conductor according to faradays law of induction.
The motor and the clutch are independent and are not in contact. Eddy currents flow in closed loops within conductors, in planes perpendicular to the magnetic field. We have emerged as prominent manufacturer, exporter and supplier of acpl eddy current drive. This industrial directory contains a broad range of controllers. For the best value on new electrical servo and industrial motors, call us at 5864690710. An introduction to eddy current testing from the ndendt resource center. Eddy current drive acpl eddy current drive manufacturer. Pulsed eddy current nondestructive testing and evaluation. Electromagnetic eddy current engineering is simply better by design. Dynamatic dcd drives eddy current drive by drive source international, inc. We have the most extensive experience, and we develop the highest quality ect inspection products. Eddy current drive consists of a totally enclosed, fan cooled tefc. In a typical vertical configuration, shown in image 3, an ordinary induction motor is mounted atop the eddy current drive. Click download or read online button to get fundamentals of eddy current testing book now.
646 69 984 1359 158 209 25 1448 656 332 1005 290 1426 855 1148 258 1275 933 1429 300 1383 81 1022 926 371 1010 803 1231 928 556 1246 248 1378 1471 8 851 1434 72 926 770 897 982 384 1086 574