Eddycurrent drives can produce more torque at low speed than an induction motor and vfd. We have the most extensive experience, and we develop the highest quality ect inspection products. Report by sae international journal of alternative powertrains. Design of an eddy current torque bypass clutch for seamless. Eddy current braking is a state of the art braking technology that has both economic and risk management advantages. 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. For me, the starting point for finding out more was this post in particular the posting by jim hardy contained lots of good links. Eddy current clutches the regutron 3 dcrs digital speed control is a costeffective way to upgrade existing analog eddy current clutch controllers. Eddy current clutches articles, news and companies related. Eddy current clutches articles about eddy current clutches. The drive unit consists of a constant speed induction motor and an integral magnetic clutch, or eddy current coupling, assembled in a common housing. Affiliated distributors applied power solutions bearing headquarters dalton bearing service, inc. Line regenerative variable frequency drives, showing capacitors top cylinders and inductors attached which filter the regenerated power.
In mountain areas where continuous braking force is needed, for a long time, the eddy current braking is very much useful for working without overheating. Electromagnetic clutch working, applications, advantages. An eddy current clutch would be highly controllable, simple to manufacture, lowcost, robust, and do not wear compared to friction clutches. Sep 02, 2014 circular eddy current brake system eddy current brake works according to faradays law of electromagnetic induction. The dynamometers have low inertia as a result of small rotor diameter. Eddy current definition of eddy current by the free dictionary.
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. Huge energy savings potential operating centrifugal fans, pumps and compressors vary frequency of electrical supply to an induction motor to vary the motor speed. Eddy current clutches give torque as a function of rpm. In mountain areas where continuous braking force is needed, for a long time, the eddy current braking. The eddy current drive or clutch is a slip device consisting of two rotating elements that. Eddy current drives instruction manual revised february 18, 2004 drive source international, inc. Eddy current brakes provide increasing torque as the speed increases, reaching peak torque at rated speed. 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 brake dynamometers wb series are ideal for applications requiring high speeds and also when operating in the middle to high power range. Eddycurrent brakes provide increasing torque as the speed increases, reaching peak torque at rated speed. Eddy current variable speed drive systems modern pumping today. 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 torque at relatively highspeed levels. The eddycurrent coupling or clutch is oldschool technology, but their robust design is appreciated by many. Isc companies magnetic technologies ltd mayr corporation motion industries.
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. A slight eddycurrent effect is present in a hysteresis brake or clutch. Eddy current definition of eddy current by the free. Note that cracks must interrupt the surface eddy current flow to be detected. Us10260571b2 clutch device with eddy current brake with. The prototype performed a seamless shift on a test bench demonstrating the viability of using an eddy current clutch for torque bypass clutches in amts. Also a time dependent study was done to show the development of the same eddy currents in the disc with deceleration. Our technology the science of eddy current magnetic braking. Hp eddy current clutch full load test electricaltest2011. Eddycurrent clutches consist of a field, tachometer, and eddycurrent control module. Eddy currents flow in closed loops within conductors, in planes perpendicular to the magnetic field. When starting eddy current clutch operates at 100% slip allow the driver motor to accelerate. In the normal clutch, a spring used to engage the clutch whereas in em clutch an electromagnetic field is used for engagement.
While full braking torque is possible independent of slip speed, eddycurrent effects can increase the dynamic braking torque over a static calibrated value by as much as 7% to 8% per rpm increase in speed. Eddy current clutch as well as fan coupling with eddy current clutch. An eddy current coupling 4 is proposed, with a first movable coupling element. Eddy current clutches eddy current clutches are so named because they in duce eddy currents into a metal cylinder or drum. The eddycurrent drive also called a magneticallycoupled adjustable speed drive, which consists of an eddycurrent clutch and associated controls, is favored for heavyduty applications with high starting torque and severe shock loads. This paper presents the design and experimental validation of an eddy current torque transfer clutch for use inside automated manual. 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. If playback doesnt begin shortly, try restarting your. Thus the transferable moment increases with the relative rpm. Its a complicated subject but very well studied in the context of eddy current brakes, where the retarding force is used to create a braking force without mechanical friction wear. 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.
The invention comprises a clutch device having an actuating device, wherein the actuating device has an electrical eddy current brake. Eddycurrent clutches and fluid couplings trade press. Eddy current drive is a combination of a constant speed ac induction motor, coupled to an eddy current clutch. Our eddy current brake technology is extremely reliable, smooth, and low maintenance. The medium of torque transmission is a controlled magnetic field, generated by a stationary. The function of an eddy current clutch is to transmit a controlled torque from the induction motor,prime mover to the load driven machine. 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. There are even nocontact clutches such as hysteresis clutch and eddy current clutch. Tech talk february 2011 eddy current drives holland industrial. Pdf design and experimental demonstration of a seamless. Figure 2 shows the schematic diagram of a simple eddy current brake with only one magnet around it.
Dec 10, 2015 eddy current clutches eddy current clutches are so named because they in duce eddy currents into a metal cylinder or drum. However, most widely used form is single face friction clutch. This easytooperate controller provides standalone control of a single magnetic drive or accurate coordination of more complex multidrive systems such as series pump applications. Design of an eddy current torque bypass clutch for.
Eddy current brakes use the drag force created by eddy currents as a brake to slow or stop moving objects. Transportation industry automotive transmissions design and construction properties electric vehicles equipment and supplies engineering design. Eddy current clutch working, application, advantages and. Sep 01, 2011 hp eddy current clutch full load test electricaltest2011. The companies featured in the following listing offer a comprehensive range of clutches.
Drive source international dsi is the worlds leading manufacturer of eddy current adjustable speed drives, brakes and controls. 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. 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. Request pdf design of an eddy current torque bypass clutch for seamless automated manual transmissions of electric and hybrid vehicles this paper. 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. The supplier of this item is approved as a verified supplier. Thank you for helping keep engtips forums free from inappropriate posts. Design and experimental demonstration of a seamless automated manual transmission using an eddy current torque bypass clutch for electric and hybrid vehicles. Since there is no contact with a brake shoe or drum, there is no mechanical wear.
The potential of eddy current clutches is assessed from a representative case study consisting of a. It is a rugged industrial drive which has been proven in the past 60 years by thousands of units in nearly every industry. Dynamatic adjustable speed drives, brakes and controls. Because eddycurrent couplings and fluid couplings are uncommon, the institutional knowledge about them is being lost. At that time, the municipality replaced their outdated analog controlling system for the eddy current clutch to a new digital dynamatic ec2000 high power clutch controller. Eddy current, as well as a variety of related products and services.
When current is removed from the clutch, the armature is free to turn with the shaft. Transportation industry automotive transmissions design and construction properties electric vehicles equipment and supplies. Eddycurrent dynamometers wb series dynamometer magtrol. We offer both aircooled and watercooled designs built with our reliable and durable eddy current technology for long service life.
Eddycurrent clutch article about eddycurrent clutch by. We provide repair services from 56 frame through 49 to 63. Eddycurrent clutch encyclopedia the free dictionary. The electromagnetic clutch comes various forms, including magnetic particle clutch and multidisc clutch. The input shaft directly coupled to the motor and variable speed output shaft is connected to load. The braking is friction free with no contacting parts. Us6585228b1 electric valve actuator with eddy current. Eddycurrent clutches and fluid couplings upcoming seminars.
A threestory high 1,650 horsepower pump, 4,160 volt synchronous motor, and eddy current drive clutch at a wastewater treatment plant went in for its routine maintenance. An electrically operated valve actuator with an eddy current clutch is disclosed. High quality eddy current testing solutions for complete inspections. They can be induced within nearby stationary conductors by a timevarying magnetic field created by an. Due to the specialized nature of applications using eddy current clutches, please contact kinetics factory sales and engineering for. Eddycurrent clutches consist of a field, ta chometer, and eddycurrent control.
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. Diagram 1 eddy current clutch and gearbox assembly 2 general. Eddy current brake design for operation with extreme back. After the motor has reached its target speed, its controller engages the eddy clutch. The eddy current brake has a brake stator with at least one coil and a brake rotor with a brake region, wherein the brake region has a first layer which is electrically conductive and which has a first lateral face and a second lateral face, the first lateral. Electromagnetic clutches operate electrically but transmit torque mechanically.
York specializes in services such as eddy current clutch repair. Welcome to the premier industrial source for clutches. In contrast to the drive and brake elements described previously, the torque in eddy current clutches and brakes fig. Determining eddy current coupling losses determining eddy current coupling losses. 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. The subsequent analysis is based on this simple model.
Determining eddy current coupling losses electric motors. An eddy current clutch relies on electromagnetic forces to create a. We doesnt provide eddy current clutch products or service, please contact them directly and verify their companies info carefully. This unique braking system takes the simple function of magnetic and nonmagnetic forces and turns it into a high tech masterpiece. Sort by date 1 controlling backlash in mammography systems. 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 ac motor rotor and clutch drum should rotate independently of the output shaft. The principle of eddy current coupling makes it possi ble to obtain a wide range of stepless, adjustable speeds directly from industrial a. Real eddy current brakes are a bit more sophisticated than this, but work in essentially the same way. Blog 5 applications of eddy current brakes head rush. The drag thus produced controls the rate at which spring 156 can urge stem. The control module supplies dc current to the clutch, which in turn causes the load to spin.
Adjustable speed drive asd, also known as variablespeed drive vsd, describes equipment. Eddy current clutches articles, news and companies. Eddy current drive characteristics the eddy current drive is the simplest of all electrical adjustable speed drives. The prime mover is an ac induction motor, the work horse of industry today. 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. A stationary study was done to evaluate the eddy current generated in the disc. 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.
Manually rotate both shafts to be sure they are free from binding and noise. Eddy current drives can produce more torque at low speed than an induction motor and vfd. The armature or rotor is constructed so that when the winding is excited with direct current, magnetic pole pieces are formed. One part of the clutch contains slip rings and a winding figure 428a. Eddy current drives are slipcontrolled systems the slip energy of which is. In most designs, springs hold the armature away from the rotor. This webinar is intended to preserve the knowledge of how they work as well as their unique repair requirements. Head rush is the only company to use magnetic eddy current braking technology in climbing, free fall, and zip line devices, and the difference shows. Variable frequency drives vfds popular speed control devices used in industrial, commercial and residential applications. Eddy current couplings ecc use a fixed speed motor connected to a drum and a wound rotor connected to the. The current will vary up and down with the voltage.
Eddycurrent brake dynamometers wb series are ideal for applications requiring high speeds and also when operating in the middle to high power range. According to this law, whenever a conductor cuts magnetic lines of forces, an emf is induced in the conductor, the magnitude of which is proportional to the strength of magnetic field and the speed of the conductor. The eddy current coupling or clutch is oldschool technology, but their robust design is appreciated by many. Because eddy current couplings and fluid couplings are uncommon, the institutional knowledge about them is being lost. Is it costeffective to replace old eddycurrent drives. The voltage is adjusted to vary the torque that is transmitted from the motor shaft to the output shaft of the clutch. Eddy current brakes are best substitutes for ordinary brakes, which are being used nowadays in road vehicles even in trains, because of their jerk free operation. Esr 0557 overhaul of eddy current clutch and gear box. Zetec is the industry leader for costeffective eddy current testing ect in complex applications. A type of electromagnetic clutch in which torque is transmitted by means of eddy currents induced by a magnetic field set up by a coil carrying direct current in. 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%. As the outer portion of eddy current clutch 2 is restrained from movement by being pinned to damper mount 86, the rate of rotation of roller shaft 112 is controlled by eddy current clutch 2. They are an adjustable speed drive and provide soft starting capability.
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