Apparatus for altering the magnetic state of a permanent magnet
First Claim
1. An apparatus for altering the magnetic state of a permanent magnet, said apparatus comprising:
- a magnetic field inducing device for generating and applying an induced magnetic field to said permanent magnet, said device being provided in circuit between two charge storage elements; and
means for transferring charge alternately in opposed directions between said storage elements through said magnetic field inducing device to generate a series of alternating polarity magnetic field pulses of decreasing magnitude in said device.
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Accused Products
Abstract
An apparatus (10) for altering the magnetic state of a permanent magnet comprises a coil inductor (26) for generating and applying an induced magnetic field to the permanent magnet. The coil inductor (26) is provided in circuit between two charge storage elements (20, 24). The apparatus also comprises a discharge control circuit (28) for transferring charge alternately in opposed directions between the storage elements (20, 24) though the coil inductor (26) to generate a series of alternating polarity magnetic field pulses (167, 191) of decreasing magnitude in the coil inductor (26) or to generate a single magnetic pulse of relatively high strength. The apparatus (10) can be operated as either a magnetising or demagnetising device and is capable of demagnetising a column of 200 or more magnets.
96 Citations
24 Claims
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1. An apparatus for altering the magnetic state of a permanent magnet, said apparatus comprising:
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a magnetic field inducing device for generating and applying an induced magnetic field to said permanent magnet, said device being provided in circuit between two charge storage elements; and
means for transferring charge alternately in opposed directions between said storage elements through said magnetic field inducing device to generate a series of alternating polarity magnetic field pulses of decreasing magnitude in said device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A method of altering the magnetic state of a permanent magnet, said method comprising:
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providing a magnetic field inducing device for generating and applying an induced magnetic field to said magnet said device being provided in circuit between two charge storage elements;
transferring charge alternately in opposed directions between said storage elements through said device to generate a series of alternating polarity magnetic field pulses of decreasing magnitude in said device.
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21. A method of changing the magnetic state of a permanent magnet, said method comprising:
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charging a first charge storage element to a predetermined level;
discharging said first storage element into a second charge storage element via a magnetic field inducing device to generate a magnetic field pulse;
discharging said second storage element into said first storage element via said magnetic field inducing device to generate another magnetic field pulse of different magnitude and different polarity than that of said previous magnetic pulse; and
repeating said discharging steps to generate a series ot alternating polarity magnetic field pulses of decreasing magnitude in said device until said permanent magnet has reached a desired magnetic state.
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22. An apparatus for changing the magnetic state of a permanent magnet to a desired magnetic state, said apparatus comprising:
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means for charging a first charge storage element to a predetermined level;
means for generating a magnetic field pulse by discharging said first storage element into a second storage element via a magnetic field inducing device;
means for generating another magnetic field pulse of a different polarity and a different magnitude than that of said previous pulse by discharging said second storage element into said first storage element via said magnetic field inducing device;
said generating means being arranged to be operated alternately to provide a series of alternating polarity magnetic field pulses of decreasing magnitude in said device.
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23. An apparatus for demagnetising a permanent magnet by spiralling it around its hysteresis loop, said apparatus comprising:
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means for generating an electromagnetic field;
first and second charge storage means connected together and to said field generating means for transferring charge between each other via said field generating means; and
control means for controlling the charging and discharging thereof so as, in use of the apparatus, to cause said field generating means to generate an alternating polarity reducing magnetic field.
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24. In or for an apparatus for altering the magnetic state of a permanent magnet by application thereto of a magnetic field of alternating polarity and decreasing strength, a control circuit for controlling the generation of said magnetic field by discharge of first and second charge storage means through a magnetic field generating means, said control circuit being adapted and arranged for transferring charge between said first and second charge storage means by way of said magnetic field generating means so as to subject a permanent magnet within the magnetic field of said magnetic field generating means to a sequence of alternating polarity magnetic impulses of progressively decreasing strength appropriate to the demagnetisation of the permanent magnet.
Specification