The rotor is the input of the clutch, which is connected to the ac motor. Typically, we rate the clutch with a gain factor k, which is gram millimetersrpm or newton metersrpm and we design the. Each magnetic clutch shall consist of a stationary frame, a ring member driven at motor speed, and a variable speed member, bearings, outer bearing bracket and housing, heat exchanger if recommended by the manufacturer, motor. Ect began largely as a result of the english scientist michael faradays discovery of electromagnetic induction in 1831. Electromagnetic brakes also called electromechanical brakes or em brakes slow or stop motion using electromagnetic force to apply mechanical resistance friction. The eddy current drive is installed between the motor and the driven equipment. Im1600002004 dcd2 through 225 eddy current drives instruction manual revised february 18, 2004 drive source international, inc. Eddy current clutches consist of a field, ta chometer, and. The companies featured in the following listing offer a comprehensive range of clutches.
The variable speed drive shall be an eddy current coupling type magnetic drive, of aircooled open type construction. An eddy current clutch input rotor is magnetized when the coil is energized with dc current. Torque is transmitted from the ac motor to the load by eddy current action when the clutch field coil is excited with dc current. Pdf the eddy current inspection method felix edafe.
Eddy current clutch as well as fan coupling with eddy current clutch. Manual transmissions of electric and hybrid vehicles. Stromag is the leader in industrial brakes, couplings, clutches and controllers. Transmission clutch inspection machine eddy current testing. Eddycurrent dynamometers wb series dynamometer magtrol.
Used to control dc drives or other variable speed drive systems. The dcd line adjustable speed drive is an integral combination of an aircooled magnetic clutch and an ac motor. Refer to figure 428 in the text book the magnetic armature and drum of the eddy current clutch. As an example, assume that there is a deep crack in the surface immediately underneath the coil see figure 8. Minster scrb52 cyclemite scr eddy current clutch control scrb52 used. For discussion purposes assume the input member is a drum rotation at a. Eddy current variable speed drive systems modern pumping today. The inductor includes a plurality of pole shoes of alternating magnetic polarity arranged in an annular ring and a plurality of permanent magnets disposed.
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%. Eddy current testing technology 1st edition be exceptional 9 7 8 0 9 9 1 7 0 9 5 2 6 isbn 9780991709526. When the motor reaches the full speed, the slip is decreased to the desired rate, providing engagement of the clutch. They were originally called electromechanical brakes, but over the years the name changed to electromagnetic brakes, referring to their actuation method. Eddycurrent systems, control drives stromag pdf catalogs.
Medical imaging equipment, water handling systems, conveyors, robotic systems and rotary and linear actuators are among the many devices that may be fitted with electric friction brakes to hold their loads in place when the power is off. The excitation system induces eddy currents on some conductive materials, producing an electromagnetic torque. Esr 0557 overhaul of eddy current clutch and gear box. After the motor has reached its target speed, its controller engages the eddy clutch. Eddy current clutches articles, news and companies. 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. How is the speed of an eddy current clutch controlled.
We have eddy current clutches running on every continent. Overhaul of eddy current clutch and gear box transport for nsw. When it comes to understanding your needs, were your trusted advisor. The paper also demonstrates during a competition in which the driver was. Request pdf design of an eddy current torque bypass clutch for seamless automated manual transmissions of electric and hybrid. Engineered for the demands of heavy industry, companies in sectors from transportation, energy, oil drilling, steel, shipping and more depend on stromag equipment and replacement parts to keep operations running and safe. Affiliated distributors applied power solutions bearing headquarters dalton bearing service, inc. Eddy current drives instruction manual revised february 18, 2004 drive source international, inc. Electromagnetic clutches brakes minneapolis, mn rapid. Because eddy current drive systems are inherently simple and require fewer full power handling components, they have significantly lower acquisition costs.
Eddycurrent loss and temperature rise in the formwound. A threestory high 1,650 horsepower pump, 4,160 volt synchronous motor, and eddy current drive clutch at a wastewater treatment plant went in. The eddy current clutch acts as a rotating transformer similar to a motor. A passive clutch based on magnetorheological fluids and eddy. Eddy current clutches articles about eddy current clutches. Stromag sas unit 87 rocco drive victoria 3179telfax.
The armature winding of the clutch is excited by direct current. Eddy current clutch download pdf info publication number us32331a. The inductor includes a plurality of pole shoes of alternating magnetic polarity arranged in an annular ring and a plurality of permanent magnets disposed intermediate the pole shoes. What is the primary advantage of an eddy current clutch over a mechanical clutch. Eddy current clutches, for one reason or another, cannot always be repaired or rebuilt. When starting eddy current clutch operates at 100% slip allow the driver motor to accelerate. Please request usps express services before making payment.
Zetec miz10a eddy current tester 10a,z3125,5864,sv for parts repair. In this video i use lenz law to explain how eddy currents form when a piece of metal passes through a magnetic field. I2 r by the induced eddy current, where r is electrical resistance of the workpiece and i is the induced current. These eddy currents create their own magnetic flux that reacts with the input rotor to transmit torque. Unlike friction brakes, where 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 force. Product manuals adjustable speed eddy current drives. Is it costeffective to replace old eddycurrent drives. Design of an eddy current torque bypass clutch for seamless automated. Sort by date 1 controlling backlash in mammography systems. Dec 10, 2015 eddy current clutches eddy current clutches are so named because they in duce eddy currents into a metal cylinder or drum. An eddy current coupling 4 is proposed, with a first movable coupling element comprising an. The clutch contains a fixed speed rotor and an adjustable speed rotor separated by a small air gap. Design of an eddy current torque bypass clutch for seamless.
In such instances, you might be interested in investing in a new eddy current drive system. 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. Eddy current testing ect as a technique for testing finds its roots in electromagnetism. This will interrupt or reduce the eddy current flow, thus decreasing the loading on the coil and increasing its effective impedance.
Demonstration of a transmission clutch inspection system using a cnc eddy current system combined with a laser inspection for precise part verification. Model dsi700 universal eddycurrent controller instruction. Also a time dependent study was done to show the development of the same eddy currents in the disc with deceleration. 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. 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. The magnetic flux of the input rotor then causes small eddy currents to flow in the nonferrous output rotor. When using a mechanical clutch, what determines how fast a load can be accelerated and the amount of initial torque applied to the load.
Please request this service before making payment and we will adjust your invoice to include the correct cost. Eddycurrent clutch article about eddycurrent clutch by. 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. Eddy current, as well as a variety of related products and services. Us3488535a permanent magnet eddy current brake or clutch. Electromagnetic brake electromagnetic clutch magnetic. Design of an eddy current torque bypass clutch for. Eddy current brakes provide increasing torque as the speed increases, reaching peak torque at rated speed. Because of our maintenance and retrofit programs, we have a chance to see how.
Eddy current brake dynamometers wb series are ideal for applications requiring high speeds and also when operating in the middle to high power range. 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. How eddy current clutches work eddy current clutches give torque as a function of rpm. A magnetomotive force mmf source either an electromagnet or a. Eddy current drives can produce more torque at low speed than an induction motor and vfd. Typically you would run eddy current clutches between 10 and 300 rpm. Eddy current clutches articles, news and companies related. 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 are so named because they in duce eddy currents into a metal cylinder or drum. An eddy current clutch ecc drive is a device used to convert constant speed rotation input into adjustable speed output. 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. The armature or rotor is constructed so that when the winding is excited with direct current, magnetic pole pieces are formed. This reduced saving was due to the removal of hysteresis and eddy current losses from the stator. Because sjogrens tensioning clutch relies on permanent magnet technology, the units are very durable and have no.
Tech talk february 2011 eddy current drives holland industrial. Instruction manuals for yaskawa legacy eddy current product called the vs motor. Eddy current drives for industrial automation dynaspede. World leader for eddy current component testing ibg prufcomputer gmbh was established in 1983 and invented the pmft, is the world leader for eddy current component testing.
Highpressure fuel pumps will be tested for flow rate and current draw, then rebuilt if necessary. An eddy current andor induct ion brake or clutch comprised of, a braking inductor and a ferromagnetic eddy current conductor arranged for relative rotation with respect to one another. Eddy current clutch working, application, advantages and. The eddy current drive or clutch is a slip device consisting of two rotating elements that are coupled by a magnetic field. They are used on roller coasters, to stop cars smoothly at the end of the ride the linear eddy current brake consists of a magnetic yoke with electrical coils positioned along the rail, which are being magnetized alternating as south and north magnetic poles. This output is isolated from earth ground to make it more. Us3601641a eddy current andor induction brake or clutch. Select an electromagnetic brake or electromagnetic clutch based on torque requirement. We are constantly fine tuning and improving our designs. The dynamometers have low inertia as a result of small rotor diameter.
Today, we have hundreds of custom designed units in use. Request pdf eddycurrent loss and temperature rise in the formwound stator winding of an inverterfed cage induction motor temperature rise of the formwound multiconductor stator winding of. A stationary study was done to evaluate the eddy current generated in the disc. The value of a clutch mechanism in electric vehicle s r. An eddy current clutch has a metal cylinder or drum with slip rings and a winding. The idea for a selfcontained drive with a motor and variable speed clutch is introduced shortly after the eddy current dynamometer derived from the words dynamo and automatic, over the years, dynamatic has become a highly recognized and respected trade name in both the us and abroad. One part of the clutch contains slip rings and a winding figure 428a. 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. Pdf design and experimental demonstration of a seamless. The value of a clutch mechanism in electric vehicle s.
Dyne systems can help provide a test system for your specific needs. Using a cnc eddy current system combined with a laser inspection, the eddy current testing system provides instant verification allowing manufacturers to detect flaws or defects in the metal as well as capture the complex internal geometry of parts without needing visual access or destroying the part. One part of the clutch contains slip rings and a winding. Eddy current testing technology eclipse scientific. Eddy current clutches are driven at a constant speed by an ac induction motor. At heco, we carry dynamatic variable speed solutions, including eddy current clutches, eddy current brakes including air cooled and. Fuel cells are changed as a matter of course as their life span is only five years even if 956 114, when it arrived, still had its original fuel cell from 1984. Transmission clutch eddy current inspection system youtube. An eddycurrent clutch is described which is provided with pole bodies which are arranged in a homopolar manner and lie with their ends at least partially axially in front of one another. Linear eddy current brakes are used on some rail vehicles, such as trains.
Document misses some of the terminology usually associated with the eddy current drive technology such as clutch, magnetic field. The pole geometry of the coupled output member imprints a pattern of alternating magnetic domains on the drum. The eddy current drive or clutch is a slip device consisting of two rotating elements that. Torque is transmitted to a variable speed output in proportion to. Welcome to the premier industrial source for clutches. What is the primary advantage of an eddy current clutch over. This webinar recording is intended to preserve the knowledge of how they.
Real eddy current brakes are a bit more sophisticated than this, but work in essentially the same way. 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. This means by increasing or decreasing the rpm, you can get infinite torque adjustment. The clutch contains a fixed speed rotor and an adjustable speed rotor separated by a. Clutch and brake coil leads 23 tachometer generator leads 23 section 4 24 operation 24. Eddy current drive is a combination of a constant speed ac induction motor, coupled to an eddy current clutch. An eddy current clutch relies on electromagnetic forces to create a coupling torque. 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. We have the most extensive experience, and we develop the highest quality ect inspection products. This includes engine testing or other rotating devices such as electric motors, wind turbines, transmissions, or drivelines. The ac motor interacts with an electromagnetic clutch that controls both the torque.
The magnitude and phase of the eddy currents will affect the loading on the coil and thus its impedance. We reserve the right to cancel transactions made in error, e. Eddy current clutches go by quite a few names, including eddy current drives, magnetic drives, magnetic clutches, or eddy current clutches. Eddy current techniques in ndeeddy current techniques in nde. Highquality eddy current testing solutions for complete inspections. 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. 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. The eddy current clutch prototype doesnt meet the torque requirement of 193 nm on the slip speed range see table 3, because of clutch geometric constraints imposed by the retro fit.
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