SYNOPSIS
These brakes designed by controlling for equipment, auto mobiles and movers are suitable for AC & DC supplies up to 12V to 220V, and are suitable for a wide range of drum sizes 10 to 380mm dia. These brakes are suitable with a rated torque ranging from 100 kg-cm for the smallest brake up to 2000 kg-cm for a 20 mm dia at 50% coil rating, i.e., the coil remains in circuit for a maximum of 5 min. out of every 10 min.
Since these brakes are in normally closed position, the release of the brake shoes is affected by energizing the electromagnetic coil which overcomes the spring force and shoes are moved clear off the drum by lever / arm linkage system so that the drum is free to rotate without any friction. When the power is given to the electromagnetic coil the coil gets energised and in turn pulls the plunger down. The plunger in turn operates the arm of the brakes and the brake opens. The design of the brake is such that as the lining keeps wearing out due to normal operation of the brake, adjusts itself on its own to achieve the rated toque. When specified, brake drum or drum coupling both pin bush type and flexible geared type can be supplied along with the brakes.
INTRODUCTION
A car has three braking system – the accelerator, the gears and the brakes themselves. A controlled, well anticipated and unhurried act of slowing down or stopping will involve the use of all the three. With proper observation of the road and traffic ahead, a driver can see the need for a reduction in speed long before he has to apply the brakes. The accelerator becomes a brake as soon as the foot is lifted from it. A period of deceleration should ideally, always precede the use of the foot brake.
Gear becomes a braking system when the vehicle is shifted to a lower gear. When approaching a hazard the procedure to be followed is first to decelerate and then application of foot brakes and finally changing to a lower gear. The third part of the braking system consisting of the brakes themselves are the most important part and it is only with this part the vehicle can be brought to rest abruptly if needed. With the other two the accelerator and the gear the vehicle loses its momentum very slowly. Electric brakes a type of the braking system not very popular can be used commercially in passenger cars as they have several advantages. Electromagnetic brakes are used in other fields such as bottling plants. They are used for bringing the assembly to a quick stop each time for filling up the bottles. In this project we propose to deal with a new type of electromagnetic brake using a solenoid switch. Most magnetic breaking relay on the attractive force generated with in a gap magnetic circuit which generate forces on the supported shaft because this force is quadratic I magnetic flux intensity in the circuit; it is only possible to pull the shaft To accomplish bi or multidirectional control of the shaft.
Several electromagnets are arranged around the shaft and are operated differentially to improve the linearity and dynamic performance of these differentially arranged magnets. It is commons to free bias the air gaps with constant flex density. This biasing can be accomplished in a number of ways but usually it is done by applying a biasing current to the oils, which energize the magnetic circuits. The primary advantages of this scheme a reduction in electrical power consumption. Magnetic bearings employ the repulsive forces of opposed magnetic fields generated by electromagnets in this slider and the base. They achieve straight line accuracy to 0.00004-inches / foot through a control loop that employs capacity, proximately sensors in position freed back for controlling the amplifiers that generate the magnetic fields. Magnetic Breaking can support loads in excess of 1000 pounds, magnetic Breaking have no moving parts to wear and can be used in vacuum condition so there is no friction in contact places.
WORKING PRINCIPLE
Electromagnetic brake works in the principle that the attractive force of the opposite pole was to be used for performing the braking system. When an electric current is passed through solenoid switch where electric field is converted into magnetic filed, plunger Reciprocates, this Reciprocating motion is connected Rotary motion through mechanical linkage and can operates the shoe.
APPLICATIONS
- Used in Crane Control System
- Used in Winch Controlling
- Used in Lift Controlling
- Used in Automobile purpose
FEATURES OF THE BRAKE
Hydraulic Brake operates on liquid pressure. In case there is a leakage in brake lines, the brake fails. The brake shoe also tends to get ruined due to this. So automobile engineering prefer to use more reliable brake like air brake which are costlier. Electromagnetic Brake which is very sensitive (concentrate only on mechanical linkage) can be used as an emergency brake. Simultaneous application of both Hydraulic and electromagnetic Brake provide more contact surface between brake shoe and drum, there by very effectively slowing the vehicle.
Another useful function of electromagnetic brake is that it can be used as an effective parking brake in slope. Here we engaged the brake shoe with stationary drum by cam hence locking the wheel from rotation.
Cost-wise Electromagnetic Brake are very cheap as the number of element are less and construction also very simple. Running cost also reduced since maintenance of the brake is not required.
This can also be used in bottling industry where conveyers are used. These conveyers are generally stopped at pre determined interval. This can be done quite simple by using Electromagnetic Brake.
DISADVANTAGES
- Braking speed is constant.
- This braking is not a smooth one.
- High Battery power is required.
- May be chance of electro-magnetic coil failure.