Bbc Brown, Boveri & Company, Limited

Asea Brown Boveri Inc.

Asea Brown Boveri Ag

Abb Research Ltd.

Roland Schuler

Gabor Liptak

Kurt Herzog

Thomas Baumann

Willibald Zerlik

Johann Schubert

Jorg Oesterheld

Michael Litenas

Zoltan Kovacs

A stator winding insulation for improving the dielectric and thermal properties of a main insulation of a conductor bar of an electric machine. The stator winding insulation includes a mica band having at least one layer-like carrier composed of longitudinal threads and transverse threads and a mica-containing layer fixed to at least one face of the carrier with the aid of a binder. In the layer-like carrier, the volume ratio of the longitudinal threads to the transverse threads is greater than or equal to 2.5:1 and a weight ratio of the mica in the mica-containing layer to the layer-like carrier in the mica band is greater than or equal to 6:1.

Stator winding insulation

In a high-voltage insulated stator winding having at least one stator winding bar (10) for an electrical machine, which stator winding bar (10) is surrounded by winding insulation (13) which comprises a plurality of insulating layers (22) arranged one above the other, in which case each insulating layer (22) is composed of an insulating material arranged on a base (16), in particular in the form of Mica paper (14), improved dielectric utilization (withstand voltage) and improved thermal utilization (heat dissipation) are achieved to an equivalent extent in that a heat-resistant plastic film is used as the base (16), which plastic film is modified by introducing a filler which can resist corona discharges.

High-voltage insulated stator winding

An electric machine having a stator winding which is impregnated by total immersion. The bar ends of the stator winding have soldering lugs which are insulated from one another and with respect to grounded housing parts. In order to simplify the assembly of the soldering lug insulation and at the same time to improve heat transfer, the soldering lugs are surrounded on all sides by a deformable insulating material with is pervious to impregnating resin. The insulating material is fixed by means of a shrinkable fabric which is likewise pervious to the impregnating resin. The insulation and shrinkable fabric are impregnated and cured at the same time as the winding insulation.

Electric machine with deformable insulation on soldering lugs

Winding rods, built into the stator of an electrical machine, are no longer safe to operate after leakages in a water chamber. After this waterchamber has been removed, as is necessary anyway, a flexible, gas-proof hose is pulled upon the rod end, and the machine-side end of the hose is attached to the rod in a gas-proof manner. The other hose end is connected to a vacuum pump and, by evacuating the hose, the water that has penetrated into the rod insulation is removed by the same route as it penetrated into the insulation. The quality of this drying process is monitored by dielectric measurements.

Process for drying the insulation of stator winding rods of electrical

To improve the thermal conductivity of the main insulation of an electrical machine, an insulating tape is proposed which is composed of one or more glass-fabric layers (6) and mica layers (5). Only essentially the interspaces of the glass fabric (6) which is made up of glass threads (7) are filled with a resin (8) which is provided with a filler containing microscopically small particles (9) having a thermal conductivity which is greater than that of the resin. To protect the glass threads (7) of the fabric, its threads (7) are provided with a protective coating (10) of resin or lacquer, said protective coating (10) essentially only surrounding the threads of the glass fabric (6), but otherwise not completely filling the interspaces of the fabric. A main insulation made up of such an insulating tape fulfils all the requirements with regard to mechanical and thermal stability and electrical strength.

Insulating tape and method of producing it

To fix the conductors and coils of wind overhangs and to fill cavities in the winding overhangs of electrical machines, strings are used which include compressible rovings (1) made up of fibers and surrounded by an elastic sheath (2) which is permeable to impregnating resin. A spacing is introduced into the winding overhangs with a thickness which is greater than the spacings to be filled. The strings are impregnated after they are pulled in. To improve the overhang corona shielding, the strings are treated with a conductive impregnating agent which is permeable to the impregnating resin before they are pulled in.

Means for fixing winding overhangs in electrical machines

The corona-shielding arrangement for the stator winding of an electric machine, comprising a semiconductive textile corona-shielding strip wound around the major insulation of slot portion and end yoke portion of each bar of the stator winding is constructed such that the slot portion (10) of the stator winding bar is wound around in at least one layer with a first semiconductive, volume-conducting coronashielding strip (24) having an approximately constant degree of overlap. The end yoke portion is wound around in at least one layer with a second semiconductive, volume-conducting corona-shielding strip (24), the degree of overlap from the exit of the bar from the stator body (14) to the bar end becoming continuously smaller. This corona-shielding arrangement is economic to produce; the voltage characteristic in the longitudinal direction of the bar is simple to optimize.

Corona-shielding arrangement for the stator winding of an electric

The conductor bars of stator windings of rotating electric machines are usually multiply wound around with two-layer mica strips as major insulation and then impregnated with synthetic resin. It is proposed to use as first layer (L1) a mica strip which is provided on both sides with a textile carrier (24, 25). The further layers (L2, L3, L4, . . .) are then wound with a mica strip (27) provided with a textile carrier (28) only on one side. A major insulation constructed in this way is very homogeneous. The textile carrier (24), preferably consisting of glass fabric, which bears directly on the conductor surface, optimizes the impregnation and produces an effective bond between the insulation and conductor.

High-voltage insulation for stator windings of electric machines

In an insulating system for high-voltage machines, a three-layer insulating tape is proposed as turn-to-turn insulation which comprises a center mica layer (1) which is covered on both sides by plastic foils (2,3) having different thickness. Thermoplastic adhesive layers (4,5) on the outer surfaces of the foils (2,3) produce an intimate bonding of the turn-to-turn insulation to the conductor elements and to the main insulation. An insulation of such construction is distinguished by a high electrical life at increased temperature and a high surge withstand capability.

High-voltage insulating system for electric machines

With stator windings impregnated by total immersion, the gap formation between main insulation (7) and slot side possibly occurring due to the different expansion of conductor material and insulation material is avoided by several successive impregnation and curing processes being made (at least two), each further curing being performed at a lower temperature level (difference about 20.degree. C.) beginning at approximately the class temperature of the insulation system and the curing being performed with horizontal stator axis, the stator being turned through at least 90.degree. C. before each further process.

Process for production of the winding of an electrical machine

Solvent-free polyurethane resin mixture

A large electrical machine, includes bar windings composed of twisted individual conductors with irregularities formed at the narrow edges of the bar winding. The bar winding is composed of individual insulated conductors and uninsulated conductors. A synthetic mica-resin putty pressed between the conductors fills the spaces between the conductors. Electrically conductive strips covering the putty are electrically connected to the uninsulated conductors.

Bar windings for electrical machines

A method of securing one or more insulated winding components in the slots of a rotary electrical machine against any displacement during operation in which one or more inserts which have a deformable and heat-hardenable characteristic such as is established by a fibrous material impregnated with a heat-hardenable resin in the B-state, are inserted in the slot in contact with the adjoining side of a winding component. The winding components and non-hardened inserts are then subjected to pressure to effect a deformation matching any tolerance irregularity in the profile of the adjacent surface of the winding component, this step being followed by a gradual heating of the inserts while still under pressure so as to harden the same, and the entrance to the slot is then closed in the usual manner by insertion of a wedge.

Method for securing winding components in the slot of a rotary electric

An arrangement for supporting insulated conductor components within the slots of the stator component of a dynamo-electric machine under compression so as to inhibit vibration thereof in which included with the one or more multi-conductor coil sections in the slot is a multi-layer resilient element including at least one felt layer and at least one hard layer, the ratio of the thickness of the felt layer to the hard layer preferably being 3 : 1 and the resilient element having a spring characteristic which is degressive in relation to the spring force.

Arrangement for supporting winding elements in the stator slots of a

A composite tape insulation for use in winding onto electrical conductors to be further processed for installation in an electrical machine comprises an internal insulation structure having a layer of glass cloth or polyester fleece and a layer of fine mica impregnated with a cured synthetic resin such as an epoxide resin, and outer facing layers of a synthetic material such as a polycarbonate resin bonded to opposite sides of the internal insulation structure by the impregnating resin. The composite tape insulation is made by passing the internal layer structure through a bath of the impregnating resin, thereafter applying the outer facing layers, heating the resulting composite structure so as to cure the impregnating resin to an intermediate B state, winding the composite structure onto the bare electrical conductor with an overlap of the order of 50%, cutting the conductor into lengths which are then shaped to the desired configuration, and then final pressing and heating the insulated and shaped conductor lengths to establish a final bond of all components and conversion of the impregnating resin to its C state.

Growing community of inventors

Wettingen, Switzerland

Roland Schuler