MAGNETIC LEVITATION Presented by-

Avik BhowmikNikita Dandwani

OUTLINE Introduction to levitation Literature Survey Magnetic Levitation - Brief Designing of ciruit Working Applications Conclusion

What is levitation? From Latin levitas "lightness" A cubical magnet levitating over a

superconducting material For levitation,Lifting force = Gravitational Force Ways to levitate objects…

Literature Survey

Different mechanisms to obtain

levititation:

Electrostatic Aerodynamic Acoustic Buoyant levitation

Water is primarily diamagnetic, so water droplets and objects that contain large amounts of water can be levitated

Different forms of Animal Levitation

Magnetic levitation Magnetic pressure is used to

counteract the effects of the gravitational and any other accelerations.

Use of magnetic fields to levitate a (usually) metallic object.

Using either Ferromagnetism or Diamagnetisim object can be leviated.

Block Diagram

Power Supply Emitter

Opto signal detector

Opto reference detector

Voltage Follower

Difference Amplifier

Compensation Network

Non-Inverting Amplifier

Coil Driver

Designing of the circuit

Designing of IR Emitter circuit

The infrared LED emitter produces a light beam across the bottom of the coil.

IR is preferable because there's less noise and ambient light than at normal optical wavelengths.

Designing of Photodetector Circuit

This opto detector measures the position of the ball by the amount of light transmitted by the infrared LED. This is a linear signal across the small area of the detector.

Amount of light controls the collector-emitter current.

A 56k resistor should be connected in series with the detector for protection purpose.

Designing of the Reference Detector

This optodetector measures the relative brightness of the infrared LED, along with the total ambient light. It provides a reference voltage to the op-amp.

Light path to it is never blocked by the object.

A 56k resistor should be connected in series with the detector for protection purpose.

Designing the Difference Amplifier

Finds the difference between the two input signals from optodetectors and amplifies it to get position of object.

The op-amp has a 100K feedback resistor Rf in combination with an 11K input resistor Ri.

This is a standard inverting amplifier with a gain of: Gain = Rf / Ri = 100K / 11K = 9.

The Levitator’s Phase Lead Network

The 150K and 22K resistors form a divider circuit. It reduces the voltage by the ratio of the two resistors. The "gain" will multiply the position signal by:Gain = 22K / (22K + 150K) = 0.128

In other words it reduces the signal by a factor of eight.

The lower breakpoint frequency is f1 = 1/(2 pi R1C) = 10.6 Hz.

The upper breakpoint requency is f2 = f1/Gain = 82.9 Hz.

Designing the Output Amplifier

• This circuit amplifies the control signal in preparation for the power output transistor

• This 741 op-amp is wired as a standard non-inverting amplifier. The gain is computed from the feedback and input resistors: Gain = (Rf + Ri) / Ri = (370K + 1.5K) / 1.5K = 247

Designing the Levitator Coil Driver

• This circuit controls the current in the electromagnetic levitation coil L1. It is driven by a 741 op-amp, which is specified to source up to 40 mA of current.

• The base resistor provides some protection.

• Diode D1 protects the transistor by safely discharging the current through coil once transistor turns off.

APPLICATIONS MAGLEV trains Magnetic bearings Magnetic ring spinning Coil guns Aluminium melting 3D cell culture Particle accelerators to

accelerate sub-atomic particles to nearly the speed of light

A DEMONSTRATIO

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QUERIES ????