Akshita Gupta

38824

AXIAL FIELD ELECTRICAL MACHINES

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CONTENTS INTRODUCTION

HISTORICAL BACKGROUND

CLASSIFICATION OF AXIAL FIELD MACHINES

DIFFERENCES BETWEEN AXIAL FIELD AND RADIAL FIELD MACHINES

MAIN CONFIGURATION OF AXIAL FIELD MACHINES

APPLICATIONS OF AXIAL FIELD MACHINES

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INTRODUCTION

All electrical machines work on the principle of Electromechanical Energy Conversion. Based on this machine topology can be of three possible arrangement:

1. Radial Field Electrical Machines.2. Axial Field Electric al Machines3. Linear Machines

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HISTORICAL BACKGROUND

The first ever machine was Axial field machine by Faraday.

They were soon replaced by Radial Field machines due to strong magnetic force.

This problem can be alleviated using sandwiched structure.

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CLASSIFICATION OF AXIAL FIELD MACHINES

For every Radial field machine there exist an analogous Axial field machine.

Axial field machines can also be classified according to the various magnetic circuits they assume. These are : 1. Single rotor and single stator 2. Rotor sandwiched between two stators.3. Stator sandwiched between two rotors.4. Multiple stator and rotor

7Magnetic circuits of the various axial machines

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DIFFERENCE BETWEEN RADIAL FIELD AND AXIAL FIELD MACHINES

Stator and Rotor cores are disc shaped .

Direction of conductor and the air gap flux .

Higher power to weight ratio. Diameter to length ratio is also very high.

Effective cooling and permits higher utilization of the active material.

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Floor space required for manufacturing is low.

Application limited to only fast responses due to shorter length.

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MAIN CONFIGURATIONS OF AXIAL FIELD MACHINES

FARADAY DISK

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PRINTED CIRCUIT BOARD(PCB) MOTORS

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1. Armature has conductors that are stamped from a sheet of copper, welded together and placed on a disc.

2. The disk armature is located between two sets of permanent magnets mounted on ferromagnetic end plates.

3. It have special geometry, high power to weight

ratio, and very high pulse torque.

4. Applications are in : Machine tools, computer peripheral equipment, robotics, large control valves.

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AXIAL FIELD MACHINES WITH YOKELESS ARMATURE CORE

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TORUS MACHINE

1. It is a slotless, toroidal-stator, permanent-magnet machine .

2. High-energy permanent magnets such as Neodymium-Iron-Boron (Nd-Fe-B) are used.

3. The winding is toroidal in nature and can have any number of phases.

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APPLICATION OF AXIAL FIELD MACHINES

VERTICALLY MOUNTED AXIAL FIELD MACHINES

1. The attraction between the stator and the rotor can be used to take in its own weight i.e. levitation force.

2. This force increases with increase in the rating of machine.

3. Application in ceiling fans ,turbo-hydro generator sets as they all are vertical.

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WIND POWER GENERATOR

1. The Torus generator can be directly coupled with

the wind turbine ,eliminating the gear box.

2. This reduces the noises and weight as well as increases the reliability and efficiency.

3. These generators can be used as small scale stand alone generating system in remote areas.

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OTHER APPLICATIONS:

ELECTRIC SCOOTER DRIVE

ADJUSTABLE SPEED PUMP DRIVE

HIGH SPEED GENERATORS DRIVEN BY GAS TURBINE

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CONCLUSION

We have seen that axial field machines have a large number of advantage over conventional machines in terms of compactness, cooling as well as find a huge application in the areas where size is the issue as in aircrafts, robotics.But the only hindrance in its path was the cost of permanent magnets which is now reducing ,thus opening more avenues for it.

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REFERENCES

‘Evolution of axial field machine 'the paper by Abdullah Al-Badi, Adel Gastil,Hadj Bourdoucen and Joseph Jervase.

‘Axial Field Electric Machines with Yokeless Armature’ thesis by C.C.Chan.

‘Axial Field machines design and construction’ IEEE paper by C.C.Chan.

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THANK YOU