EP0702504A2 - Tube thermique et méthode pour le chauffage par induction d'ensembles électriques imprégnés - Google Patents

Tube thermique et méthode pour le chauffage par induction d'ensembles électriques imprégnés Download PDF

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Publication number
EP0702504A2
EP0702504A2 EP95114461A EP95114461A EP0702504A2 EP 0702504 A2 EP0702504 A2 EP 0702504A2 EP 95114461 A EP95114461 A EP 95114461A EP 95114461 A EP95114461 A EP 95114461A EP 0702504 A2 EP0702504 A2 EP 0702504A2
Authority
EP
European Patent Office
Prior art keywords
tube
thermal
thermal tube
primary circuit
inductive heating
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP95114461A
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German (de)
English (en)
Other versions
EP0702504A3 (fr
Inventor
Joachim Dr.-Ing. Sabinski
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
VEM-Elektroantriebe GmbH
Original Assignee
VEM-Elektroantriebe GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by VEM-Elektroantriebe GmbH filed Critical VEM-Elektroantriebe GmbH
Publication of EP0702504A2 publication Critical patent/EP0702504A2/fr
Publication of EP0702504A3 publication Critical patent/EP0702504A3/fr
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/02—Induction heating
    • H05B6/10—Induction heating apparatus, other than furnaces, for specific applications
    • H05B6/105—Induction heating apparatus, other than furnaces, for specific applications using a susceptor
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/02—Induction heating

Definitions

  • the invention relates to a device and the method for inductive heating, in particular for curing and drying impregnated windings of electrical machines with concentrated or distributed winding in electrical engineering.
  • the insulation system determines the resilience and the lifespan of the products. High mechanical, electrical and thermal properties of the insulation of the windings are required. This can only be achieved by combining different insulating materials and reactive resins, e.g. Epoxy resins or silicone resins. This insulation means that air pockets are excluded.
  • DE 33 23 154 discloses a method for impregnating and embedding electrical windings which partially avoids these disadvantages.
  • the reaction resin and the windings are first dried and then impregnated or cast using a vacuum pressure process. Drying and degassing in ovens is supported by current heat in the electrical conductor of the winding. The temperatures that can be achieved are up to 140 ° C. This is followed by further curing in normal drying ovens at higher temperatures.
  • This process has the disadvantage that the heating period is still relatively long and further curing in normal drying ovens is required.
  • the invention has for its object to provide a device and a method for inductive heating of impregnated or non-impregnated electrical assemblies of electrical machines, which allows a high heat input in a short period of time, improves the efficiency of heat generation and the heat sources in and immediately and concentrated at the optimal point and thus simplifies the heating of the component and enables both resin securing and complete curing.
  • the primary and secondary heat sources act directly on the component to be hardened.
  • the advantages result from the direct heat radiation at the right place and the optimal air flow for the convective heat input into the respective assembly and an optimal heat conduction within the assembly to be heated. This results in the advantages of making the temperatures more uniform, shortening the curing time and improving thermal efficiency.
  • the device according to the invention is used for drying and curing components of electrical machines impregnated with impregnating varnish or resins, in particular primary circuits 1.
  • a composite sheet metal tube 2, also referred to as a thermal tube 2 is used as the secondary circuit 2.
  • the thermal tube 2 consists of an inner tube 3 with ferromagnetic properties, in the exemplary embodiment preferably from an approximately 3 mm thick iron tube.
  • the outer tube 4 consists of a nonferromagnetic but electrically good conductive material, preferably a 1 mm thick copper tube in the exemplary embodiment. In the outer tube 4, which is closer to the primary circuit 1, heat is generated by the alternating field action of the primary circuit 1 via eddy currents which are associated therewith.
  • an alternating voltage ⁇ 0.4 U N is applied to the primary circuit 1, which also generates heat in the winding of the primary circuit 1.
  • the thermal tube 2 is the secondary heat source and the winding of the primary circuit 1 is the primary heat source.
  • the AC voltage can have a frequency of 50 Hz, but other frequencies are also conceivable.
  • the voltage connection in three-phase stands is three-phase, but can also take place in a different phase, for example two-phase when the phase connections change over time.
  • the AC voltage generates a rotating field in the stator winding or when connected ⁇ 3-phase alternating field in the stator bore.
  • the rotating or alternating field passes through the thermal tube 2 which is fixed in the stator bore.
  • the iron portion of the inner tube 3 concentrates the magnetic yoke of the field while increasing the flux and also contributes, although to a lesser extent than the outer tube 4, via the action of eddy currents for heat generation.
  • the thermal tube thus represents the main heat source for the process.
  • the final temperature and the time constant of the temperature profile in the thermal tube 2 can be set both via the stator voltage (primary circuit voltage), its frequency and also via the air gap 5 between the thermal tube 2 and the primary circuit 1.
  • the uniform heating in the drying and curing process requires an air gap 5 of approximately 20 mm to 70 mm.
  • the thermal tube 2 consists of at least two or more circle segments 6.
  • the construction of the thermal tube 2 in the exemplary embodiment comprises four circular segments 6, two circular segments 6 each being connected in pairs via hinges 7.
  • the length of the thermal tube 2 corresponds at least to the largest laminated core length of a primary circuit 1.
  • the thermal tube 2 is locked to the primary circuit inner bore by means of an adapter using the contact pressure due to the thermal expansion of the thermal tube 2 or by means of a cross 9 with elongated holes, preferably over the centering edge of the primary circuit 1.
  • the circle segments 6 of the thermal tube 2 are preferably connected by flexible electrical conductors 8 and can overlap. For better handling and adjustment of the The device can be arranged on the inside of the thermal tube 2 in the area of the hinges 7.
  • a fan is arranged in a thermally insulated envelope structure, which circulates the air through the primary circuit bore on both sides of the thermal tube 2 and over the primary circuit outside.
  • the combination of the heating of the primary circuit winding and the thermal tube 2 acts primarily on the winding-slot-tooth areas which are decisive for the dielectric strength, as a result of which the temperatures of the winding in the slot and winding head area and over the main insulation in the slot area become more uniform compared to conventional heating. This forms the basis for shortening the heating-up time and achieving the degree of curing of the main insulation faster, which technically leads to a shortening of the curing time.
  • the device of the embodiment includes a three-phase connection.
  • the voltage is regulated in 20% steps via a control transformer.
  • the inductively loaded and heated module is compensated on the secondary side of the transformer.
  • the voltage setting of the transformer is regulated via the measured values of the process-determining temperatures on the assembly to be hardened.
  • the compensation system switches on at 20% of the heating voltage and compensates automatically at the beginning of the process.
  • the respective set capacity is maintained during the drying and curing process.
  • the process can also be run with 20% to 40% of the heating voltage.
  • the effect of the thermal tube 2 is brought back to the comparable end temperature by shortening the air gap 5 by shortening the thermal time constant and thus increased significantly.
  • the main heat source in this process is therefore the thermal tube 2.
  • the heat source primary circuit winding acts due to the smaller current that comes in square, only subordinate.
  • the three-phase winding can also be connected to voltage in two phases.
  • the primary circuit 1 as the excitation circuit can be inside and the outside around the primary circuit 1 is the thermal tube 2.
  • This variant is used for drying and curing the rotors of electrical machines. If the rotor is a short-circuit rotor, a high frequency must be used in the excitation circuit.
  • the thermal tube 2 can also consist only of a non-ferromagnetic but electrically highly conductive material.
  • the normally inner tube 3 of the composite sheet is then omitted. This reduces the amount of heat that is required to heat the thermal tube 2.
  • the entire curing process can be divided into three process steps.
  • the resin is gelled in the winding area in the shortest possible time. A resin fuse thus occurs.
  • the resin layer should be quickly warmed up to the temperature at which the polymerisation of the resin begins (e.g. in epoxy-anhydride systems approx. 85 °) where the closed nature of the resin system is particularly important with regard to insulation C).
  • This phase is completed in this resin system due to the lower mobility of the molecular groups at approx. 120 ° C.
  • the third phase corresponds to the conventional curing phase. Due to the rapid reaching of the curing temperature also in the winding area, the overall process is shortened.
  • the elimination of the first phase may also be desired. Nevertheless, the method enables a constant temperature rise over all areas of the component to be hardened with almost the same energy savings.
  • the resin lock can still be carried out within the impregnation container after the impregnation process has been completed.
  • the insulating parts with their low thermal conductivity support this process, as a result of which the iron parts do not influence the draining of excess resin.
  • the frequency of the voltage should be matched to the respective resin.
  • the connections can be changed.
  • the thermal conductivity of the thermal tube 2 ensures temperature compensation on this.

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Manufacture Of Motors, Generators (AREA)
EP95114461A 1994-09-16 1995-09-14 Tube thermique et méthode pour le chauffage par induction d'ensembles électriques imprégnés Withdrawn EP0702504A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4432978 1994-09-16
DE19944432978 DE4432978C2 (de) 1994-09-16 1994-09-16 Vorrichtung und Verfahren zur induktiven Erwärmung getränkter elektrischer Baugruppen

Publications (2)

Publication Number Publication Date
EP0702504A2 true EP0702504A2 (fr) 1996-03-20
EP0702504A3 EP0702504A3 (fr) 1996-12-18

Family

ID=6528357

Family Applications (1)

Application Number Title Priority Date Filing Date
EP95114461A Withdrawn EP0702504A3 (fr) 1994-09-16 1995-09-14 Tube thermique et méthode pour le chauffage par induction d'ensembles électriques imprégnés

Country Status (2)

Country Link
EP (1) EP0702504A3 (fr)
DE (1) DE4432978C2 (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19644187A1 (de) * 1996-10-24 1998-04-30 Vem Elektroantriebe Gmbh Verfahren und Einrichtung zum Vorwärmen, Imprägnieren und Aushärten von Imprägniermitteln in Wicklungseinzelteilen sowie deren Baugruppen elektrischer Maschinen
DE10360285B4 (de) * 2003-12-20 2005-10-13 Gottlob Thumm Gmbh Vorrichtung zum Einbringen von Imprägniermitteln in elektrische Bauteile

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2181274A (en) * 1938-05-11 1939-11-28 Utilities Coordinated Res Inc Induction heater construction
GB679127A (en) * 1949-07-26 1952-09-10 Robert Harry Barfield Containers for heating by induction
DE902416C (de) * 1951-07-29 1954-01-21 Carl Schoerg Dipl Ing Vorrichtung zur induktiven Beheizung von Rohren, Gefaessen u. dgl.
DE3323154A1 (de) * 1983-06-27 1985-01-03 Siemens AG, 1000 Berlin und 8000 München Verfahren zur impraegnierung und einbettung von elektrischen wicklungen
DE3534091A1 (de) * 1985-09-25 1987-04-02 Philips Patentverwaltung Vorrichtung zum verbinden von keramikteilen mittels glaslot
DE4139541A1 (de) * 1991-11-30 1993-06-03 Bosch Gmbh Robert Verfahren zum verbinden einer elektrischen wicklung mit einem eisenkern

Also Published As

Publication number Publication date
EP0702504A3 (fr) 1996-12-18
DE4432978C2 (de) 2001-02-08
DE4432978A1 (de) 1996-03-28

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