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Contenido archivado el 2022-12-27

APPLICATION OF ENERGY FOR PREHEATING AND CURING THE IMPREGNATION OF ELECTRICAL MACHINES

Objetivo

The aim was to develop an energy-saving process and the necessary equipment for curing vacuum-pressure impregnated stators. The developed prototype of a direct heating furnace ensures low energy consumption in the curing of the stator assembly. The new solution was to provide the following improvements on the classical hardening process in a convection furnace:
A reduction of approx. 15% in the energy levels needed for each assembly during preheating/curing; a reduction of approx. 10.25% of solvent/curing agent losses or the escape of low-molecular groups from the resin, which reduces environmental pollution; a reduction of approx. 33% in the preheating period for the respective resin system; more even temperature rise in the components minimising temperature differences in the component (35%); elimination of rotating curing and achievement of a uniform curing degree, which results in lower equipment/tool costs; a reduction (50%) in the total furnace volume for the same useful volume.
The direct heating furnace has the following advantages over convection furnaces :
- A reduction of approx. 15% in the necessary energy input per component for preahting curing
- A reduction of approx. 10-25% of the solvent and curing agent losses or of the escape of low-molecular groups from the resin, which means less environmental loads and improved quality parameters
- A reduction of approx. 33% in the heating time within the limits of the respective resin system
- A 35% more even heating of the component with minimum temperature differences inside the component (quality parameters).
- The elimination of rotary curing and achievement of a uniform curing, which means lower fixture and tool costs
- A reduction of 50% in the furnace volume for the same useful volume
- The elimination of furnace waggons and the associated chargin surface.
The running operating costs are determined by the consumed energy. 75 kWh are used for the curing of one stator of shaft height 500 mm, and forthe simultaneous curing of two stators approx. 110 kWh.
In contrast to convection furnaces with their exclusively secondary energy absorption via circulating air, the newly developed direct heating furnace ensures the heating of the component primarily through heat conduction and secondarily through radiation with a temporary convective component by running a current through the windings: The unit comprises the following components :
- Power section, regulated with compensation equipment
- Furnace envelope (lid), insulated and foldable
- Universal tool component and
- Registering unit for temperature/time regulation.
The power section provides the necessary heat energy according to the programmed preheating and curing times. The universal tool component ensures an even heating of the component via radiation and a temporary convective component. As opposed to convection furnaces, the furnace envelope has no fittings for air-guiding and heating systems. Thus it has no other function than that of a heat insulator, and the useful space ofthe furnace is identical with the evaporation space which means a considerable reduction in size. The design of the furnace has been simplified so that furnace doors and furnace waggons are no longer necessary. The furnace is designed in such a way that the furnace space can simultaneously be used for charging. The furnace envelope can be halved. The test report proving adherence to curing parameters comes from the registering unit and can be called up.
The shorter preheating time and reduced convection (by an amount smaller than 10%) guarantees optimal incorporation of, for example, the curing agent into the resin system, where rotary curing of the components is not necessary, eliminating associated tool and fixture costs. This also leads to a smaller furnace room. The furnace volume is 50% smaller than that of convection furnace.

Convocatoria de propuestas

Data not available

Régimen de financiación

DEM - Demonstration contracts

Coordinador

VEM-ELEKTROTANTRIEBE GMBH
Aportación de la UE
Sin datos
Dirección
FOERSTERLINGSTRAßE 20
01259 DRESDEN
Alemania

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Coste total
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