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These drawbacks of ordinary brakes can be overcome by a simple and effective mechanism of braking system 'The eddy current brake'. It is an abrasion-free method for braking of vehicles including trains. It makes use of the opposing tendency of eddy current Eddy current is the swirling current produced in a conductor, which is subjected to a change in magnetic field. Because of the tendency of eddy currents to oppose, eddy currents cause energy to be lost. More accurately, eddy currents transform more useful forms of energy such as kinetic energy into heat, which is much less useful.

In many applications, the loss of useful energy is not particularly desirable. But there are some practical applications.

Such an application is the eddy current brake. PRINCIPLE OF OPERATIONS Eddy current brake works according to Faraday's law of electromagnetic induction. 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. Download Lagu Masa Lalu 3 Via Vallen there. If the conductor is a disc, there will be circulatory currents i.e. Eddy currents in the disc.

According to Lenz's law, the direction of the current is in such a way as to oppose the cause, i.e. Movement of the disc. Essentially the eddy current brake consists of two parts, a stationary magnetic field system and a solid rotating part, which include a metal disc.

During braking, the metal disc is exposed to a magnetic field from an electromagnet, generating eddy currents in the disc. The magnetic interaction between the applied field and the eddy currents slow down the rotating disc. Thus the wheels of the vehicle also slow down since the wheels are directly coupled to the disc of the eddy current brake, thus producing smooth stopping motion. EDDY CURRENT INDUCED IN A CONDUCTOR.

Essentially an eddy current brake consists of two members, a stationary magnetic field system and a solid rotary member, generally of mild steel, which is sometimes referred to as the secondary because the eddy currents are induced in it. Two members are separated by a short air gap, they're being no contact between the two for the purpose of torque transmission. Consequently there is no wear as in friction brake.

Stator consists of pole core, pole shoe, and field winding. The field winding is wounded on the pole core. Pole core and pole shoes are made of east steel laminations and fixed to the state of frames by means of screw or bolts. Copper and aluminium is used for winding material the arrangement is shown in fig. This system consists of two parts. Rotor Stator:- It is suppored frame members of the vehicle chassis. It has introduced magnetic poles energized by windings.

Current is supplied to the winding from the battery. Rotor:- It is a rotating disc, which is fitted on the line of crankshaft with small air gap to stator. When disc rotates a flux change occur in the section of the disc passing the poles of stator. Due to the flux change there is a circulatory or eddy current in the disc around the magnetic lines of force. The effect of this eddy current induces ‘N’ and ‘S’ poles at the surface of the disc.

Then there will be a ‘drag’ or braking effect in between eddy current induced poles and magnetic poles in the stator. By changing current from the battery we can change the braking force. In this breaking system kinetic energy of the vehicle is converted to heat and this heat is dissipated through the rotating disc. Total resistance of field winding R = L/A where, L = total length of field winding in meter. =Resistivity of the wire in ohm meter A=the area of cross section of field winding in m2 Total no: of terms = total length /mean length of one term The rotor is a rotating disc on shaft, which is placed very near to the stator with small air gap (1 mm to 2 mm). Rotating disc may be one or both side of stator.

The two units have common ring member, poles cores on which winding are provided being fixed to ring number. If a malleable casting is employed, then the pole core could be cast integrally with the right. After fitting the windings on the cores, poles shoes are fitted to provide pole faces of appropriate shape and area. The rotor disc should be provided with properly designed fins for faster heat removal. The magnetic circuits of the two units are substantially the same, non-undue and thrust would be imposed on the motor bearings. Slight axial displacement of rotor could however, cause quite appreciable discrepancy, the air gap of two units.