FR2473807A1 - IMPROVEMENTS ON SINGLE-PHASE CAPACITOR-INDOOR INDUCTION MOTORS - Google Patents

Abstract

The capacitor-start single-phase induction motor has a rotor R ', the slots of which are inclined on the axis of the rotor at an angle of 7 to 11 degrees. Thus, the speed of the rotor varies as a function of the load according to a constantly decreasing law. Such a motor finds an important application in washing machines. (CF DRAWING IN BOPI)

Description

Improvements to single-phase induction motors with start-up

capacitor

  The invention relates to single induction motors

  phased type capacitor start. It aims to provide such engines whose torque variation curve has a slope different from the normal slope and which retains the favorable characteristics of induction motors, such as silent operation and the

long-term reliability.

  The induction motors according to the invention

  a particularly important, though not exclusive, application in electric washing machines, since they make it possible to

  successive operations of washing, distribution of

  three-speed centrifugal spin drying

  different, whereas only two speeds are

  currently available when using induction motors.

  This possibility represents a considerable advance

  in the industrial sector concerned. Indeed, if we already have on the market of washing machines that use three different speeds for washing,

  linen distribution and spinning, these machines use

  read switching motors that do not have the

  characteristics of non-noisy operation and reliability

  bility of induction motors. But this is a matter of

  features particularly appreciated by users

washing machine readers.

  The desired modification of the slope of the curve representative of the couple was obtained by the applicant,

  surprisingly, by a modification of the rotor con-

  to change the inclination of the rotor slots. The applicant has managed, as a result of experiments, to vary the speed of the rotor with respect to the stator.

  function of the load, according to a more or less

  notone and decreasing, approximately linear to

  from zero velocity (corresponding to the ma-

  maximum) (up to the maximum speed (corresponding to the idling) by giving the slots an inclination of between 70 and 110, advantageously equal to 90.degree.

  about. This inclination is to be compared with the

  normal clinching, between 20 and 30.

  The invention will be better understood when reading

  the following description of particular modes of

  of the invention, given as non-exemplary

  limiting. The description refers to the drawings which

accompany him, in which

  FIG. 1 is a diagrammatic view of a rotor of

  inductor whose slots are inclined, normally, about 30 on the axis of the rotor - Figure 2, similar to Figure 1, shows a rotor

  induction motor according to the invention.

  tion, whose slots are inclined 90 on the axis of the rotor;

  FIG. 3 is a diagrammatic sectional view of a model

  improved induction reactor according to the invention; FIGS. 4 and 5 are representative curves

  showing the variation of the torque as a function of the

  rotation speed of the motor, in the case of an induction motor currently available on the market

  (Figure 4) and a motor having a rotor according to

vention (Figure 5).

  We see in Figures 4 and 5 that the law of

  The torque c of the motor as a function of the speed of rotation n is clearly modified as indicated below. The experiments carried out by the Applicant have shown that by further modifying the inclination 0 '' of the rotor slots on the axis of the rotor shaft A ', the above results are still obtained, but at the expense of

  the reliability of the engine. Indeed, we can no longer

  when getting an automatic start of the engine.

  In FIG. 1, the rotor, its shaft and the angle of inclination of the slots are respectively designated R, A and E. In FIG. 3, C 'designates the carcass

  of the induction motor, S 'denotes the stator and V' the

  stator bearing. In Figure 2, R 'eto' desires

  the rotor and the angle of inclination of the slots

  improved engine according to the invention.

  To appreciate the importance of the invention, it should be noted that, in induction motors used up to now, the inclination of the slots at the minimum angle, between 2 and 30 allowed a minimum variation

  speed depending on the load. But this

  feature is not essential for use

  d3u induction motor in a washing machine.

  The invention is obviously not limited to

  particular embodiment which has been shown and described, and it should be understood that the scope of this patent extends to any variant remaining within the scope of equivalences. For example, the inclination of the slots may be different from that which has been shown and these slots may be oriented with respect to the axis

  in the opposite direction to that shown in the figures

res.

4 247380?

Claims (3)

REVENDI CATIONS   1.- Single-phase induction motor with start-up   capacitor, comprising a rotor provided with slots,   in that the slots of the rotor are inclined on   the axis of the rotor at an angle of between 7 and 110,   that the speed of the rotor relative to the stator decreases monotonically as a function of the load, with a substantially linear law of variation of the motor torque.   2. Induction motor according to claim 1,   characterized in that the slots of the rotor are inclined 90 on the axis.   3. Motor according to claim 1 or 2, characterized   rised in that it is incorporated in a washing machine Laundry.