Complex load test setup using a dc generator, dc motor, dual gearboxes, and a 2000hp3600rpmac motor to accomplish a full load test of a hp water cooled eddy current. The pole geometry of the coupled output member imprints a pattern of alternating magnetic domains on the drum. The clutch contains a fixed speed rotor and an adjustable speed rotor separated by a. General information about eddy current clutches and brakes. York specializes in services such as eddy current clutch repair. The principle of eddy current coupling makes it possi ble to obtain a wide range of stepless, adjustable speeds directly from industrial a. Eddy current drives that are simple, rugged, and reliable. They are a type of variable speed drive system which depends on an electromagnetic clutch to vary the output speed and torque of a constant speed motor. Eddy current clutches go by quite a few names, including eddy current drives, magnetic drives, magnetic clutches, or eddy current clutches.
Once calculated, these parameters can be used to select the proper size brake or clutch from the technical data provided in the hysteresis product data sheets. Welcome to the premier industrial source for clutches. Pdf design and experimental demonstration of a seamless. The use of the eddy current clutch provides an actuator that can control the rate of closing of the valve in a predetermined linear manner to avoid slamming the valve shut in an emergency shutdown.
Eddy current clutches, brakes, controllers distributor. The following suggested repair actions are based on accepted industry standards. They are available in standard and high speed models with many speed and torque versions. Figure 1 the control supplies dc voltage to the drive field coils and automatically varies drive excitation to maintain desired speed, torque, tension, position, or horsepower, as determined by the feedback signal. In the basic form, the eddy current drive consists of an ac motor and an electrically controlled magnetic clutch. The function of an eddy current clutch is to transmit a controlled torque from the induction motor,prime mover to the load driven machine. The drive unit consists of a constant speed induction motor and an integral magnetic clutch, or eddy current coupling, assembled in a common housing. Does anyone have a schematic of this eddy controller. This means by increasing or decreasing the rpm, you can get infinite torque adjustment. An eddy current clutch ecc drive is a device used to convert constant speed rotation input into adjustable speed output. Us3601641a eddy current andor induction brake or clutch. Eddy current variable speed drive systems modern pumping today. The possibility does exist that tubes could contain defects andor leaks which are not detectable, such as those at or near the tube end. Torque is transmitted to a variable speed output in proportion to.
Eddy current clutches the regutron 3 dcrs digital speed control is a costeffective way to upgrade existing analog eddy current clutch controllers. Seminar on eddy current brake report pdf download learn. The kinetics svr1ec speedregulated, eddy current clutch field exciter is a scr regulated rectifier system specifically designed for the application of supplying regulated variable dc power, via a closed feedback loop system, to the field coil of an eddy current clutch adjustable speed drive. Mainly this system is purely based on faradays laws of electromagnetic induction and lenzs law. Let our skilled technicians get your cyclemite eddy current clutch control back in operation quickly. Minster machine co scrb52 cyclemite eddy current clutch control. Us3488535a permanent magnet eddy current brake or clutch. Permanent magnet eddy current brake or clutch download pdf info publication number us3488535a. Typically you would run eddy current clutches between 10 and 300 rpm. Seminar on eddy current brake report pdf download abstract. Drive source international dsi is the worlds leading manufacturer of eddy current adjustable speed drives, brakes and controls. Request pdf design of an eddy current torque bypass clutch for seamless automated manual transmissions of electric and hybrid vehicles this paper. Eddy currents are circular electric currents that are induced by a magnetic field in a conductor and consist of a fixed speed motor and an eddy current clutch. When a magnet falls through a metal pipe, such as copper or aluminum tube, it creates eddy current on the walls.
Electromagnetic clutch working, applications, advantages. In a linear eddy current brake, the conductive piece is a straight rail or track that the magnet moves along. Design of an eddy current torque bypass clutch for seamless. Diagram 1 eddy current clutch and gearbox assembly 2 general. We provide repair services from 56 frame through 49 to 63. Apr 30, 2010 what is eddy current eddy currents are currents induced in conductors to oppose the change in flux that generated them. Real eddy current brakes are a bit more sophisticated than this, but work in essentially the same way. Our eddy current dynos are simple, cost effective, torque measuring devices for a large range of test purposes. Eddy current clutches and brakes heat up considerably due to the development of eddy currents with increasing rpm with temperature increase the value of the torque attainable decreases considerably. As you know that by the effect of eddy current the heat which is produced is not utilized for any useful work as they are a major source of energy loss in ac machines like transformer, generators, and motors.
Electromagnetic clutches operate electrically but transmit torque mechanically. When starting eddy current clutch operates at 100% slip allow the driver motor to accelerate. Typically, we rate the clutch with a gain factor k, which is gram millimetersrpm or newton metersrpm and we design the clutch to have an operating. Step 1 click the green button above to add the part and complete the rma form. The dynamometers have low inertia as a result of small rotor diameter. In the eddy current clutch, a static dc current produces a magnetic field in the air gap, coupling the rotating input drum and the output rotor. We have the most extensive experience, and we develop the highest quality ect inspection products. Dynaspede offers a comprehensive range of eddy current clutches, brakes or clutch brake combinations from fractional through integral horsepower range for applications demanding close unidirectional or bidirectional control of. Maintaining constant material tension during windup supports product quality and keeps your operation running smoothly. Eddy current brake dynamometers wb series are ideal for applications requiring high speeds and also when operating in the middle to high power range. This easytooperate controller provides standalone control of a single magnetic drive or accurate coordination of more complex multidrive systems such as series pump applications. An experienced drive technician can dismantle an eddy current variable speed drive or clutch, to its individual components, give a full report on the status and quote the repairs needed to get the eddy current variable speed operational to original specifications.
The eddy current drive is installed between the motor and the driven equipment. Dynaspede offers a comprehensive range of eddy current clutches, brakes or clutchbrake combinations from fractional through integral horsepower range for applications demanding close unidirectional or bidirectional control of torque at relatively highspeed levels. However, unlike friction brakes, in which the drag force that stops the moving object is provided by friction between two surfaces pressed together, the drag force in an eddy current brake is an electromagnetic. One part of the clutch contains slip rings and a winding figure 428a. Variable frequency drives and dc drives operate by electronically altering. An eddy current coupling 4 is proposed, with a first movable coupling element. Get more information about eddy current brakes pdf download by visiting this link. Us3488535a us3488535da us3488535a us 3488535 a us3488535 a us 3488535a us 3488535d a us3488535d a us 3488535da us 3488535 a us3488535 a us 3488535a authority us united states prior art keywords eddy current pole magnets permanent magnet flux prior art date 19670922 legal status the legal status is an assumption and is not a legal conclusion. Since the eddycurrent clutch is a torque transmitter, it has no inherent speed sense. Most of us are old enough to remember the oil filter commercial tag line, pay us now or pay us later. Tech talk february 2011 eddy current drives holland industrial. Eddy current clutch as well as fan coupling with eddy current clutch.
How dynamatic technology works adjustable speed drive system. Aftermarket services, like remanufacturing, can be more costeffective solution. Adjustable speed drive asd, also known as variablespeed drive vsd, describes equipment. By controlling this dc power to the field coil, the output speed can be regulated. While full braking torque is possible independent of slip speed, eddy current effects can increase the dynamic braking torque over a static calibrated value by as much as 7% to 8% per rpm increase in. The eddy current drive or clutch is a slip device consisting of two rotating elements that. Eddycurrent clutches and fluid couplings upcoming seminars. The eddy current coupling or clutch is oldschool technology, but their robust design is appreciated by many. An eddy current drive, also known generically as a magnetic drive, eddy current clutch or magnetic clutch, is an electromechanical variable speed drive that. These ruggedly constructed clutches require no brushes, slip rings or commutators. This webinar is intended to preserve the knowledge of how they work as well as their unique repair requirements. The eddy current drive also called a magneticallycoupled adjustable speed drive, which consists of an eddy current clutch and associated controls, is favored for heavyduty applications with high starting torque and severe shock loads. An eddy current clutch would be highly controllable, simple to manufacture, lowcost, robust, and do not wear compared to friction clutches.
Electronic pulsewidthmodulated pwm variable frequency drives vfd may be costeffective replacements for aging or highmaintenance eddy current drives that are used with variable torque loads, such as centrifugal fans or pumps. The mathematical methods employed in solving the relevant problems are. The electromagnetic clutch comes various forms, including magnetic particle clutch and multidisc clutch. This is known as an eddy current it circulates similar to the manner created by an eddy of water. Diagram 1 eddy current clutch and gearbox assembly 2 general this standard is to be used in conjunction with the manufacturers maintenance instructions, drawings and technical information, listed herein, for the respective eddy current clutch. Variable frequency drives and dc drives operate by electronically altering the input power to control the speed of the motor. 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. Because eddy current couplings and fluid couplings are uncommon, the institutional knowledge about them is being lost. Since 1984 magnetic technologies have been designing and manufacturing high quality permanent magnet brakes, clutches and couplings. Eddy current brakes use the drag force created by eddy currents as a brake to slow or stop moving objects. The direction of the induced emf and eddy current will be determined by applying flemings right hand rule. Dynamatic is not just eddy current drives and controls, with over 65,000 available wear parts for all makes and models of eddy current drives, even those no. An electrically operated valve actuator with an eddy current clutch is disclosed. Eddy current definition of eddy current by the free dictionary.
Eddy current drive consists of a totally enclosed, fan cooled tefc. Eddy current clutches or eddy current slip coupling are available in a broad range of sizes and speed up to thousands of kilowatts in both vertical and horizontal configurations. Eddy current, as well as a variety of related products and services. In an investigation aimed at halting n uisance tr ipping in gts po wer distr ibution system, the clarksville facilitys plant engineer determined that the 150hp motor and eddy current clutch drive system were responsible for bottlenecking the production process. Zetec is the industry leader for costeffective eddy current testing ect in complex applications. Well, those oil filters are made in a facility in greenville oh and are stamped out on several large stamping presses. There are even nocontact clutches such as hysteresis clutch and eddy current clutch. After removing sample tubes to confirm the inspection results, a determination of corrective action. Because sjogrens tensioning clutch relies on permanent magnet technology, the units are very durable and have no. The potential of eddy current clutches is assessed from. Eddycurrent clutch article about eddycurrent clutch by. The companies featured in the following listing offer a comprehensive range of clutches.
In eddy current clutches and brakes the temperature coefficient of the copper is considered along with the temperature coefficient of the magnet. Watercooled couplings wcs couplings eddy current coupling. Eddy current clutches give torque as a function of rpm. Eddy current brakes provide increasing torque as the speed increases, reaching peak torque at rated speed. Eddy current clutches and brakes manufacturers and. They are an adjustable speed drive and provide soft starting capability. The medium of torque transmission is a controlled magnetic field, generated by a stationary. Pdf eddy current braking and simulation of a magnet. High quality eddy current testing solutions for complete inspections. The armature or rotor is constructed so that when the winding is excited with direct current, magnetic pole pieces are formed.
Eddy current clutch working, application, advantages and disadvantages mecholic no comments eddy current clutches or eddy current slip coupling are available in a broad range of sizes and speed up to thousands of kilowatts in both vertical and horizontal configurations. An eddy current andor induction brake or clutch comprised of, a braking inductor and a ferromagnetic eddy current conductor arranged for relative rotation with respect to one another. As the eddy current circulates in the core, it will produce a heating effect. In the normal clutch, a spring used to engage the clutch whereas in em clutch an electromagnetic field is used for engagement. Eddy current clutches or eddy current slip coupling are available in a broad range of sizes and speed up to thousands of kilowatts in both vertical and. In this work we studied the phenomenon of eddy current braking. Design and experimental demonstration of a seamless automated manual transmission using an eddy current torque bypass clutch for electric and hybrid vehicles. An eddy current drive, also known generically as a magnetic drive, eddy current clutch or magnetic clutch, is an electromechanical variable speed drive that uses a constant speed motor as the input. Eddy current clutch working, application, advantages and. They were first proposed in the 19th century by the brilliant french physicist jeanbernard leon foucault also the inventor of the foucault pendulum and one of the first people to measure the speed of light accurately on earth. Step 2 print the rma form and put it in a box with the parts for repair. Us6585228b1 electric valve actuator with eddy current. This is an electric braking system which works on the principle that eddy current produced in it opposes the driving torque.
Eddy current is the swirling current produced in a conductor, which is subjected to a change in magnetic field. Design of an eddy current torque bypass clutch for. In other words, the rotation of the eddy current clutch assembly 6 generates eddy currents in the inductor segments 33, 34 and 35 resulting in a driving torque being created which operates to rotate and drive the clutch rotor assembly 29 at a speed which is less than that of the clutch assembly 6. Eddycurrent clutches and fluid couplings trade press. In a circular, disk or rotary eddy current brake, the conductor is a flat disk rotor that turns between the poles of the magnet. Eddy current dynamometers dynos providing precise control and low maintenance. The eddy current clutch acts as a rotating transformer similar to a motor. The eddycurrent drive or clutch is a slip device consisting of two rotating elements that are coupled by a magnetic field. Dec 10, 2015 eddy current clutches eddy current clutches are so named because they in duce eddy currents into a metal cylinder or drum.
Since there is no contact with a brake shoe or drum, there is no mechanical wear. To properly size a brake or clutch, the operating parameters of maximum torque t, slip speed rpm, and kinetic power watts will have to be determined. Eddy current transmission drive kingstone model works. Eddy current drives instruction manual revised february 18, 2004 drive source international, inc. Electromagnetic eddy current engineering is simply better by design. Jan 23, 2014 this feature is not available right now. Eddy current drives can produce more torque at low speed than an induction motor and vfd. Without external control, output speed depends on load.
Eddy current drive is a combination of a constant speed ac induction motor, coupled to an eddy current clutch. Serving the world with industrial versatility, torspec variable speed drives offer the ultimate in drive reliability with many years of applications. 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. It is caused when a conductor is exposed to a changing magnetic field due to.
However, an eddy current brake cannot provide a holding torque and so may be used in combination with mechanical brakes, for example, on overhead cranes. The potential of eddy current clutches is assessed from a representative case study consisting of a. The clutch contains a fixed speed rotor and an adjustable speed rotor separated by a small air gap. Hysteresis brakes and clutches a slight eddy current effect is present in a hysteresis brake or clutch. Eddy current clutches eddy current clutches are so named because they in duce eddy currents into a metal cylinder or drum. 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%. An eddy current brake, also known as an induction brake, electric brake or electric retarder, is a device used to slow or stop a moving object by dissipating its kinetic energy as heat. We can repair your minster machine co scrb52 in our facility. Is it costeffective to replace old eddycurrent drives. An eddy current drive sometimes called a dynamatic drive, after one of the most. When the clutch is actuated, current flows through the electromagnet producing a. 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.