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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
N
QUERIES ????