Electricity: single generator systems – Automatic control of generator or driving means – Speed or frequency of generator
Patent
1985-02-13
1986-12-09
Skudy, R.
Electricity: single generator systems
Automatic control of generator or driving means
Speed or frequency of generator
310 68D, 310165, 310198, 318773, H02P 900
Patent
active
046282459
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to D.C. excitation systems for A.C. multipolar dynamoelectric machines and is particularly concerned with brushless excitation systems arranged to produce variable pole numbers in the rotor windings of such machines.
2. Description of the Related Art
In many cases it is possible to vary the speed of a motor or the frequency of an alternator by varying the pole number. However, known arrangements for generating variable pole numbers require relatively complicated switching arrangements and/or require large numbers of slip ring connections.
SUMMARY OF THE INVENTION
1. Objects of the Invention
An object of the present invention is to alleviate such disadvantages.
2. Features of the Invention
According to one aspect of the present invention, a variable pole number D.C.--excited winding arrangement for a dynamoelectric machine comprises a closed loop of three or more series-connected rotor winding sections and at least first, second and third current-supply terminals at respective interconnections of said winding sections, the pair of winding sections common to said first current supply terminal being wound so as to generate magnetic poles of opposite senses when fed in parallel and the pair of winding sections common to said second current supply terminal being wound so as to generate magnetic poles of opposite senses when fed in series, current supply means comprising respective first and second rotating rectifiers connected to independently energisable exciter windings being provided for energising said winding sections via either said first or said second current supply terminal according to the exciter winding which is energised, so as to reverse the current through at least one of said winding sections and thereby vary the pole number.
The winding arrangement may comprise a plurality of interconnected loops of three or more series-connected winding sections.
Each common terminal is designated "even" or "odd" according to whether the pair of winding sections to which it is common generate magnetic poles at the rotor-stator interface of the same or of opposite senses when fed in parallel from the common terminal in question.
The or each loop may incorporate four or more winding sections defining at least one odd terminal and at least one even terminal, the current supply means being arranged to feed the or each said loop via either the odd terminal or the even terminal according to the pole number required.
Two or more winding sections may be wound on a common core so as to generate a single magnetic pole at the rotor-stator interface. Said two or more winding sections may be incorporated in the same or in different loops.
Additional groups of series or parallel-connected winding sections may be connected in series with the or each loop of winding sections.
Said exciter windings may be incorporated in a common exciter and magnetically linked to two or more independently exciter field windings so disposed that each exciter winding is exclusively energisable by a respective one of said field windings. Said field windings are preferably stator windings.
According to another aspect of the invention a variable pole number D.C.--excited rotor winding arrangement for dynamoelectric machine comprises a plurality of closed loops of rotor winding sections, at least two of said loops being connected in series and current supply means comprising respective first and second rotating rectifiers connected to independently energisable exciter windings, wherein said current supply means is adapted to energise different pairs of current supply terminals of the rotor winding sections according to the pole number required.
Each loop may incorporate four winding sections.
Two or more winding sections may be wound on a common core so as to generate a single magnetic pole at the rotor-stater interface. Said two or more rotor winding sections may be incorporated in the same or in different loops.
The invention includes within its scope dynamoel
REFERENCES:
patent: 3361953 (1968-01-01), Neval
patent: 3479543 (1969-11-01), Drexler
patent: 3577002 (1971-05-01), Hall
patent: 3858107 (1974-12-01), Yarrow
patent: 4004211 (1977-01-01), Takao
patent: 4024455 (1977-05-01), Yarrow
patent: 4338534 (1982-07-01), Broadway
patent: 4454465 (1984-06-01), Greene
patent: 4459502 (1984-07-01), El-Antably
patent: 4477767 (1984-10-01), Cotzas
Associated Electrical Industries Limited
Skudy R.
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