Electrical generator or motor structure – Dynamoelectric – Rotary
Patent
1993-06-29
1996-08-06
Skudy, R.
Electrical generator or motor structure
Dynamoelectric
Rotary
310254, 310261, 318701, H02K 1900
Patent
active
055436749
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a rotating dynamoelectric machine such as a variable-reluctance motor, comprising a stator magnetic circuit provided with windings in and a rotor magnetic circuit.
The stator magnetic circuit can be either inside the rotor magnetic circuit as in FR-A-2329097 which describes a wheel-motor in which the electrical phases are distributed angularly about the axis of rotation Z, or outside as in FR-A-2203212 in which the single-phase structures are juxtaposed along the axis of rotation Z.
If the magnetic circuits are formed by stacks of thin metal sheets along the axis Z, cutting-out of these sheets calls in both cases for substantial tool equipment and results in losses of material. Furthermore, in the case of FR-A-2203212, the flux has to pass from one sheet to another through parasitic reluctances.
DE-A-2302323 also describes juxtaposed structures. The stator magnetic circuit and the rotor magnetic circuit are each formed by an assembly of eight independent angular sectors each constituted by metal sheets, the plane of which passes substantially through the axis of the motor. The stator sectors have a U shape and straddle a phase winding and the rotor sectors are rectangular. There is little loss of material, there is no longer any joint reluctance and the flux path is as short as possible.
However, in order to have sufficient core cross-sections, it is found necessary to have one stack of metal sheets per sector. It is also preferable to have an airgap area of small length in order to reduce its perimeter along which are formed fluxes having low-efficiency fringes. Closure by overlapping of an airgap is accordingly carried out sheet by sheet and abruptly in the case of each sheet instead of simultaneously in the case of all the sheets and progressively in the case of each sheet. This results in considerable core losses since the flux has to be established abruptly in the case of each sheet and has to pass from one sheet to the adjacent sheet in order to spread out.
DE-A-2727450 describes a synchronous or stepping motor composed of a plurality of single-phase structures juxtaposed coaxially with an axis of rotation. Each structure comprises in accordance with FIGS. 6 and 7:
a stator magnetic circuit constituted by an assembly of stator angular sectors arranged in a circle about the axis of rotation, each sector as seen in a direction tangential to the axis f rotation being given a U-shaped profile having two arms, the entire series of arms of the sectors being provided at the free ends of at least one set of arms with a row of stator teeth;
a stator winding coaxial with the axis of rotation and housed within U-shaped sectional members of the stator magnetic circuit;
a rotor magnetic circuit in which provision is made for two rows of rotor teeth each located opposite to one row of stator teeth so as to constitute two annular rows of airgaps.
If the permanent magnets 19 and 20 were suppressed, this would result in variable-reluctance operation.
In accordance with the above-mentioned patent document, the magnetic circuits are of soft magnetic material in either sintered or massive form with joints. In both cases, substantial core losses result. Furthermore, sintered parts involve high tooling costs and a limitation of the size of motors.
In order to be able to operate at high speeds and therefore at high switching frequencies, it is desirable to make use of metal sheets of small thickness having oriented grains. It is difficult, however, to form a stack of sheets which have a thickness of 0.1 mm, for example, and which lack rigidity. Assembly rivets have to be insulated, bring about a loss of core cross-section, and do not make it possible to have a stack of sheets which are tightly clamped together over their entire surface. Moreover, the preferred orientation of the grains cannot correspond at all points to the passing of the flux which changes direction. Finally, assembly of these metal sheets is costly and liable to impair their insulating film.
T
REFERENCES:
patent: 1212544 (1917-01-01), Neuland
patent: 3855486 (1974-12-01), Binder et al.
patent: 3930175 (1975-12-01), Chirgwin
patent: 4223255 (1980-09-01), Goldman et al.
patent: 5365137 (1994-11-01), Richardson et al.
Radio Energie
Skudy R.
LandOfFree
Dynamoelectric machine composed of sectors having transverse flu does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Dynamoelectric machine composed of sectors having transverse flu, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dynamoelectric machine composed of sectors having transverse flu will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2193206