FR2787941A3 - Synchronous motor, with reduced leakage flux, for lift has aluminium ring comprising stator, placed in synthetic resin, and helping cooling of stator - Google Patents

Abstract

Motor has ring (12) comprising stator (6) placed near windings heads hence reducing leakage flux. Ring helps cooling of stator. Stator is placed in synthetic resin (7) touching ring and helping cooling of stator.

Description

The present invention relates to a synchronous motor with axial flow, with magnets

  permanent, with reduced leakage flow, for elevators.

  These types of motors are traditionally produced either with a notched stator which receives the winding, or with a stator without a notch. It is then constituted by a torus of magnetic material of the Fe Si Mo type, for example, which

receives the ring winding.

  The drawback of the notched stator is that there is a large leakage flow in the coil heads and that the resistance of the winding is

increased by these coil heads.

  In addition, the notches can generate felt torque harmonics.

in the elevator cabin.

  The leakage flow is harmful because it does not contribute to obtaining the motor torque, on the other hand the resistance of the winding produces losses by Joule effect which

  are detrimental to engine performance.

  The arrangement according to the invention makes it possible to obtain a reduced leakage flow.

  The motor indeed comprises a stator of a known type constituted by a toroid

  made of ferromagnetic material and a ring winding thereon.

  This stator is protected, near the coil heads, according to a first characteristic by an aluminum ring or any other non-magnetic metal. This

  ring forms part of the motor casing.

  The use of this aluminum ring prevents a large leak flow. It remains localized in the coil head already geometrically reduced by the use of

ring winding.

  This leakage flow cannot be diverted and amplified by the nearby presence of a

ferromagnetic metal.

  The aluminum ring partially forming a carcass contributes, according to a second characteristic, to the cooling of the stator because the conductivity

  The thermal performance of aluminum is much higher than that of steel or cast iron.

  According to a third characteristic, the stator is embedded in synthetic resin which contributes to the dissipation of heat by contact with the aluminum ring.

  The accompanying drawing illustrates the invention.

  Figure 1 shows in section the complete elevator motor except

  of the traditional electromagnetic brake.

  The motor consists of a carcass (1) which allows the motor to be fixed to

the ground or on a beam.

  This carcass supports the drive shaft (2) of a traction sheave (3) by cables (4), a traditional method for driving the elevator car on the one hand

and the counterweight on the other hand.

  The pulley is secured to a brake drum (5).

  The ring stator (6) embedded in synthetic resin (7) is sandwiched between two rotors (8 and 9) integral with permanent magnets (10 and 11). These two rotors drive the shaft (2). The stator and the two rotors are enclosed on the one hand by the carcass (1),

  the aluminum ring (12) and a cover (13).

  1 0 The shaft (2) also drives an encoder of a known type (14) necessary for

speed control.

  The motor according to the invention is particularly intended for elevators.

Claims (3)

  1 / - Synchronous motor with reduced leakage flow characterized in that it comprises an aluminum ring or an equivalent material from a magnetic point of view (12) which encloses a stator (6) in the vicinity of the coil heads, which has for effect of   reduce the leakage flow by not deflecting it.   2 / - Arrangement according to claim 1 characterized in that the ring in   aluminum (12) contributes to the cooling of the stator (6).   3 / - Arrangement according to claims 1 and 2 characterized in that the stator   (6) is embedded in a synthetic resin (7) which comes into contact with the ring   aluminum and contributes to the cooling of said stator.