Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K15/00—Processes or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines
  • H02K15/12—Impregnating, moulding insulation, heating or drying of windings, stators, rotors or machines
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F27/00—Details of transformers or inductances, in general
  • H01F27/08—Cooling; Ventilating
  • H01F27/10—Liquid cooling
  • H01F27/12—Oil cooling
  • H01F27/14—Expansion chambers; Oil conservators; Gas cushions; Arrangements for purifying, drying, or filling
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/49—Method of mechanical manufacture
  • Y10T29/49002—Electrical device making
  • Y10T29/4902—Electromagnet, transformer or inductor

Definitions

• the life of a transformer depends greatly on drying, the di ⁇ electric in which its windings are immersed and that of its solid insulators which moreover must not have suffered from the heating to which they were subjected to be dried. Similarly, no trace of air should remain or be trapped during filling-impregnation-po ⁇ polymerization.
• these operations are carried out in two stages: first drying in an oven heated with air or kerosene for a period depending on the size of the transformer but which is always more than several hours to reach several days.
• the process which is the subject of the present invention consists in causing the heating necessary for the drying of the active parts (2) by circulating, generally in the primary windings, a high frequency current. produced by a generator (9), to obtain losses by Joule effect.
• the frequency and intensity are determined for each type of transformer either by an abacus or by an automaton.
• Heating therefore begins from inside the coils (8) and is diffused by contact to the outside (secondary) (8a) and to the interior (magnetic core) (10). This heating being done in a vacuum, practically all the losses by radiation are eliminated, from where a significant gain of energy; and the three windings being connected to control devices such as a thermostat (11) and a mehometer (12), it is possible to control the temperature so that at no time does it exceed the temperature limit of solid insulators (class ' B 105 ° C for example).
• the state of the drying is in turn controlled by the megometer which indicates the insulation resistance, which makes it possible to follow this drying - but above all to stop it as soon as it is sufficient, that is to say to say that the resistance to isolation has reached a stable value.
• a calibrated level (14) with which the rod (15) is fitted makes it possible to put under a pressure determined by the winding-oil temperatures and calculated by the tomato oil inside the tank.
• an oil dryer which consists of a chute (16) through which the oil arrives and which trickled on each side of a panel constituted by a fabric or a thin mesh (17), thus providing an exchange surface practically double that of the panel under a small thickness (slot of the chute).
• the transformer terminals remained connected to the measuring devices to check the insulation resistance.
• the vacuum is only interrupted when this resistance is correct.
• the oil volumes being low, it is possible to equip one or two walls of the false tank of the oil dryer (6) described above. With this process, heating and drying are extremely fast and the time required is divided by five to seven compared to traditional methods.
• the vacuum volume is very low since the false tank is designed for a single device. It is advantageous to make the false tanks as and when required and to have them of various sizes, their construction being very simple and suitable for the installation of vacuum, heating and control.
• the polymerization When the polymerization must be carried out under vacuum, it is the molds which are heated. Regardless of the fact that their manufacture is more complicated, the polymerization, therefore the solidification, is done from the outside inwards and it is the windings which support all the stresses, unlike the patented process. More generally, the mold filled under vacuum is placed in an oven where the entire resin is mass polymerized with weak parts formed by the support and centering bridges which, although made of the same material, are present interfaces to facilitate pathways and microcracks. With the present method, the windings to be encapsulated (fig.
• FIG. 1 shows an individual installation with a false tank supporting the vacuum (IA) into which are introduced the parts acti ⁇ ves (2) to dry-impregnate with the materials ensuring operations and their control: generator (9), cabinet control (4) and control, oil tank (5), vacuum pump (7).
• generator (9), cabinet control (4) and control generator (9), cabinet control (4) and control, oil tank (5), vacuum pump (7).
• Figure 2 shows the process applied to a large production with a complete autoclave (A) replacing the false tank and being able to contain the desired number of devices, the active parts (2) already in their tank (1) and connected to the generator ( 9) and to the command and control cabinet (4), the tank to the oil tank (5).
• An oil drying device (6) can be added thereto as well as means for recording the results (3).
• FIG. 3 shows the process applied to a large power transformer with its tank (the), the generator (9), the control and command cabinet (4), the oil tank (5), the vacuum pump (7) and the recording means (3), etc.
• FIG. 4 shows a particular application to the encapsulation-polymerization of windings (8) by the same high frequency heating process of the windings to provide the heat necessary for the vacuum polymerization of the resin.
• Figure 5 shows the oil drying device in the auto ⁇ clave (A) with the chute (16), the panel consisting of the fabric (17) and the gutter (19) which collects the oil (5h ), the oil tank (5) and the circulation pump (20) with the sealed pipes (18) for recycling.

Landscapes

• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Insulating Of Coils (AREA)
• Drying Of Solid Materials (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=9387348

Family Applications (1)

Country Status (5)

Cited By (1)

Families Citing this family (10)

Family Cites Families (13)

• 1989
  • 1989-11-09 FR FR8914872A patent/FR2654249B1/fr not_active Expired - Fee Related
• 1990
  • 1990-10-12 EP EP90916023A patent/EP0454805A1/de not_active Withdrawn
  • 1990-10-12 WO PCT/FR1990/000739 patent/WO1991007764A1/fr not_active Ceased
  • 1990-10-12 JP JP2514781A patent/JPH05505279A/ja active Pending
  • 1990-10-12 US US07/720,516 patent/US5258594A/en not_active Expired - Fee Related

Non-Patent Citations (1)

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