The cap15b relay is a threephase, highspeed induction cup power relay. Cwc and cwp the type cwc and cwp relays are induction disc type relays used for directional ground fault protection on grounded neutral power systems. This relay in nothing but one version of induction disc relay. Every induction disc type relay works on the same well known ferraries principle. An induction disc type relay according to claim 2, including a singular input coil mounted on said core structure to which said input signal is applied. The actuating force for contacts movement is developed by a moving conductor that may be a disc or a cup,through the interaction of electromagnetic fluxes due to fault currents.
The shaded pole structure the watthourmeter structure the induction cup and double induction loop structures the single induction loop structure. Here, an aluminum or copper disc is placed between the poles of an ac magnet which produces an alternating flux. The operating characteristics of the more commonly used protective relays. Principle of induction type relays electrical concepts. Gnana swathika electromagnetic relays subtypes attracted armature induction disc printed disc. An induction relay works only with the alternating current.
In induction disc type of relays, disc is the moving element on which the moving contact of relay is fixed whereas in the case of induction cup the contact is fixed on the cup. Protective relays relay electromagnetic induction free. View and download abb coq instruction leaflet online. Actuating force is developed in a movable element that may be a disc or. The initial force is developed on the moving element that may be disc or another form of the rotor of the. The number of poles in the protective relay depends upon.
In these relays, a metallic disc is allowed to rotate between the two electromagnets. Induction cup structures are more efficient torque producers than either the shaded pole or the watthour meter structure. The number of poles in the protective relay depends upon the number of winding to be accommodated. Here, an aluminum or copper disc is placed between the poles of an. Power system ii lab manual jis college of engineering. The rotor in an induction motor can not turn at the synchronous speed. Based on experimental results, obtained from tests on three relays from different manufacturers, it is verified that the. These relays work on the principle of the induction motor or an energy meter. This type of relay is necessary for voltage control and reactive power control of network busses and load busses. These induction overcurrent relays are used to disconnect circuits or apparatus when the current in them exceeds a given value. Subhash technical campus, junagadh362001, gujarat india dr. So this type of relay has very high speed and may have an operating time less then 0. The induction cup structure relay works on similar principle of an induction disc relay. The electromagnetic relay is mainly classified into two types they are electromagnetic attraction relay and electromagnetic induction relay.
Relay type vdg is an inverse time undervoltage protection of ac circuits, capacitors, rectifiers and machines such as induction motors. Feb 03, 2018 this is a demonstration of the working of an induction disc relay. Westinghouse induction type overcurrent and directional overcurrent relays i contacts j t1rf. Electromagneticinduction relays use the principle of the induction motor. The different types of structure that have been used for an induction type relay are commonly called. The induction type nondirectional overcurrent relay has a construction similar to a watthour meter, with slight modification. Induction type overcurrent relays used in power system. Due to the replacement of the disc with an aluminum cup, the inertia of the rotating system is significantly reduced.
On the relay, the moving element rotor is usually a metal disk, although. The relay has a high torque movement to ensure consistent timing even under adverse conditions, and a low burden and overshoot. It consists of two windings namely primary winding and secondary winding. Adjustment of the time setting is made by rotating a knurled moulded disc against a graduated time multiplier scale. Different types of relays used in protection system and their. Electromagnetic relay working types of electromagnetic relays. The torque is produced in the disc by the interaction of one of the magnetic fields with the currents induced in the disc. Current from the secondary induces an electromagnetic field which exerts a force on the disc.
When i test induction disc relay type is the pickup value. Jun 27, 1972 an induction disc type relay according to claim 1, wherein said disc is mounted on a shaft having a bias spring provided therefor to impart a bias torque to said disc in one of said directions. Under voltage relay can have instantaneous characteristics for armature type construction or inverse characteristics induction, disc type construction depending upon design. Analysis of overtravel in induction disc overcurrent relays. The fig shows how an induction disc type over current relay with split pole i. Type cdg 14 extremely inverse time overcurrent and earth fault relay a high set overcurrent unit type. The second unit is an induction disk, ac operated, adjustable timing unit. Closeup of an inductiontype overcurrent unit, showing the disc rotor and drag magnet. The induction disc type relay is based on the same principle as that of an ammeter or a volt meter, or a wattmeter or a watt hour mater. The initial force is developed on the moving element that may be disc or another. Testing induction disc overcurrent relays westinghouse type co general electric type iac the following procedure outlines the most efficient manner to consecutively perform all tests on an overcurrent relay.
Mho relay is normally used for protection of ii descriptive questions 1. Record time dial position as found in your application. Included in the relay are two sets of shading coils and reluctance paths responsive to the same input signal for applying the. A little demo of a pair of inversetime overcurrent relays, as would be found at a substation. Gnana swathika electromagnetic relayssubtypes attracted armature induction disc printed disc dynamometer permanent magnet moving coil polarized moving coil. Actuating force is developed in a movable element that may be a disc or other form of rotor of nonmagnetic currentconducting material by the interaction of electromagnetic fluxes with eddy currents that are induced in the rotor by these fluxes. Download manual of induction disc type cdg 61 relay alstom. The shadedpole structure as shown in figure below is generally actuated by current flowing. An induction relay essentially consists of a pivoted aluminium disc placed in two alternating magnetic fields of the same frequency but displaced in time and space. Induction type relay construction detail electrical concepts.
The protective relay is the device that responds to signals from the transducers by quickly initiating or allowing a control action to be implemented in order to prevent damage to the faulted equipment and to restore service as soon as possible. The initial force is developed on the moving element that may be disc or another form of the rotor of the nonmagnetic moving element. The actuating force for contacts movement is developed by a moving conductor that may be a disc. The figure below shows the constructional of nondirectional induction type overcurrent relay. In these relays, a metallic disc is allowed to rotate.
Because of its low pickup, this device is basically a reverse power relay. The shape of the disc usually is that of a spiral since the. Cv1 and cv2 undervoltage relays ments, other than those covered under set tings, should be required. Behavior of induction disc overcurrent relays as a. Latching relays are the same as the singleside stable relays described previously except that the core, yoke, and armature are made from semihard magnetic material and there are at least two coils in the relay. This is a demonstration of the working of an induction disc relay. It is not intended for use as a fault protective relay.
The induction type relays are also called magnitude relays. The coils of the electromagnets are energised with the help of alternating currents. Type cdg 11 overcurrent and earthfault relay general description a nondirectional heavily damped induction disc relay which has an adjustable inverse timecurrent characteristic with a definite minimum time. An induction disc type relay adapted to apply to an induction disc a rotational torque proportional to an input so that an operating output is produced at the expiration of a predetermined time dependent on the magnitude of the input after the application of the input. Derive the torque equation for electromagnetic relays when used for a. An induction type relay is a splitphase induction motor with contacts. Based on experimental results, obtained from tests on three relays from different manufacturers, it is verified that the equivalent overtravel time can be considered constant for a wide range of settings in the device. A model of idor as a function of the frequency is developed.
A common type ofzelay used for timed overload protection is a thennal overload relay. The overcurrent relay operates when the current in the circuit exceeds a certain preset value. Induction cup relay modern induction cup relays have 4 or more poles the relays can be responsive to voltage and current the double actuating quantity relay can be responsive to both voltage and current the operating time characteristics depends on the type of structure modern induction cup relay. Depending on the type of rotor whether a disc or a cup, the relay is known as an induction disc or an induction cup relay.
These are of several types like shaded pole, watthour and induction cup structures and are mostly used as directional relays in powersystem protection and also for highspeed switching operation applications. Internal schematic of the type cv8 199 volt internal schematic of the type cv8 67 volt relay in type ft21 case. These relays are for protecting feeders, transformer windings, and ac machines based on forgetfully. Type cdg 14 extremely inverse time overcurrent and earth. These relays use permanent magnet or parts with a high remittance to remain the armature at the same point as. The primary winding carries the relay current i 1, while the secondary winding is connected to the lower electromagnet. The watthour structure type relay works as an electromagnetic induction type of watthour a meter so named, after it. Subhash technical campus, junagadh362001, gujarat india. Every induction disc type relay works on the same well. Basic relays electromagnetic attraction and induction relays. When no suitable station battery is available, the circuit opening type relay. This explains induction relays types shaded pole relays,watt hour meter relays,induction cup relays. With relay oriented so that the disc is level, rotate the disc to the point the contacts just make.
Discuss the fundamental requirements of protective relaying. In induction relay the deflecting torque is produced by the eddy currents in an aluminium or copper disc by the flux of an ac electromagnet. Electromagnetic and static relays principle of operation and construction of attracted armature, balanced beam, induction disc and induction cup relays. Vector diagram for maximum torque in a currentcurrent inductiontype. Model was successfully verified with experimental results. Directional over current relay linkedin slideshare. This relay can be four pole or eight pole depending on the number of windings accommodated. Braking due to magnetic fluxes created by operative current is considered.
With limited functionality and identical operating characteristics for around 100 years, you would think that we have all agreed on the right way to test an induction disc relay. Minimum oil circuit breakers, air blast circuit breakers, vaccum and sf6 circuit breakers. Aug 31, 2018 the induction disc type relay is based on the same principle as that of an ammeter or a volt meter, or a wattmeter or a watt hour mater. Induction disc type relay mainly consists of one rotating disc. This principle says, a torque is produced by two phase displaced fluxes, which is proportional to the product of their magnitude and. Induction type relay these are used as protective relays in ac systems alone and are usable with dc systems. Jan 21, 2015 a little demo of a pair of inversetime overcurrent relays, as would be found at a substation. Behavior of induction disc overcurrent relays idor is analyzed. In order to induce an emf in the rotor, the rotor must move slower than the ss.
Non indirectional induction overcurrent relay construction. These relays are for protecting feeders, transformer windings, and ac machines. Type co circuit opening overcurrent relay instruction leaflet. To find more books about download manual of induction disc type cdg 61 relay alstom pdf. Actuating force is developed in a movable element that may be a disc or other form of rotor of non. Operating principles, directional type, 24 singlequantity type, 22 induction relays. The above figure shows the wattmeter type induction relay. Induction disk inversetime overcurrent relays youtube. It con sists of a steel ball resting between two hemispherical cup jewels, one fixed in the. A unit widely used in regulating and protective relays, in which alternating current applied to a coil produces torque to rotate a disk explanation of induction disk relay. Induction cup relay electromagnetic induction inductor scribd. It consists of a pivoted aluminium disc arranged to rotate freely between the poles of two electromagnets. Description relay type vdg is a heavily damped, frequency compensated induction disc relay with adjustable inverse timevoltage characteristic. Induction disk relay article about induction disk relay by.
Sep 01, 2018 induction cup relaythis relay in nothing but one version of induction disc relay. Induction relays are available in many variations to provide accurate pickup and timecurrent responses for a wide range of simple or complex system. Apr 26, 2018 an induction type relay is a splitphase induction motor with contacts. The force is developed by the interaction of electromagnetic fluxes with eddy current, that is induced in the rotor by these.
Induction motor damage curves motor thermal limit curve ieee 620, ieee guide for the presentation of thermal limit curves for squirrel cage induction machines rotor temperature limits during starting stator temperature limits during running. These two fluxes which are mutually displaced both in angle and in position. Induction cup relay working principle construction and types. Induction cup relay work in same principle of induction disc relay. Conversely, ten induction disc relays of the same model will have identical functionality that is rather limited compared to their digital counterparts. Ca generator differential relay is a single phase, induction disc type with inverse timing characteristics. Electromagnetic relay working types of electromagnetic. An induction disc type relay according to claim 1, wherein said disc is mounted on a shaft having a bias spring provided therefor to impart a bias torque to said disc in one of said directions. It is provided with one operating winding and two restraining windings without taps. Inaccuracies due to the calibrated knob for the dial are considered. This relay is also called earth leakage induction type relay. As the name implies, the relay is designed to operate when more than a predetermined amount of current flows into a particular portion of the power system. Reactance relay is normally preferred for protection against. Closeup of an induction type overcurrent unit, showing the disc rotor and drag magnet most electromechanical relays are typically rated for minimum input to output isolation voltages of 1500 to 2000 vac.
The overcurrent relay is the simplest type of protective relay. In induction disc type of relays, disc is the moving element on which the moving contact of relay is fixed whereas in the case of induction. Jan 20, 2017 induction type relay these are used as protective relays in ac systems alone and are usable with dc systems. The basis construction of this relay is just like four poles or eight pole induction motor. An induction disc type relay adapted to apply to an induction disc a rotational torque proportional to an. It consist of an electromagnetic system which operates on moving conductors generally in the form of disc or cup function through the interaction of electromagnetic flux. Circuit breakers 2 description and operation of following types of circuit breakers.
The electromagnetic relay operates on the principle of a splitphase induction motor. Behavior of induction disc overcurrent relays as a function. However, if the rotor stopped or even if it slowed significantly, an emf. Gnana swathika types of protective relay electromagnetic or electrothermal static microprocessor based.