真空浸漆绝缘工艺研究

真空压力浸漆绝缘工艺研究

Insulation Technology Study about Vacuum Pressure

Impregnation

1 真空压力浸漆（简称：VPI）绝缘工艺

1 Vacuum Pressure Impregnation (VPI) Insulation Process

VPI-真空压力浸渍工艺是将工件预烘去潮后冷却，置于真空环境中，排除白坯线圈内部的空气和挥发物，依靠真空中漆液重力和线圈毛细管作用，以及利用干燥的压缩空气或惰性气体，对解除真空后的浸渍漆液施加一定压力的作用，使漆液迅速渗透并充满绝缘结构内层。在国内，目前VPI还是一种间隙作业的绝缘工艺。工件的滴干工序在浸漆罐内进行，其干燥工序一般另设容器或烘箱进行，方式有真空干燥、常压静置干燥或旋转干燥。The process of VPI-Vacuum pressure impregnation technology is to cool the workpiece after pre-baking and dehumidify, then put it into vacuum environment and exhaust air and volatiles inside the coil. After that put pressure on the impregnation varnish liquid by depending on the action between liquid gravity and coil capillary and utilizing dry compressed air or inactive gas, then the varnish liquid will penetrate and be full of inner of insulation. So far, the VPI process is a discontinuous operation at home. The process of drip-dry works in impregnation cans. And the drying process works in the other heating devices, the methods

include vacuum drying, stranding drying at ordinary pressure and rotating drying.

VPI-工艺流程：⊙→预烘除湿→入罐→真空排气→真空浸漆→压力浸渍→压力排漆→卸压滴漆→出罐→固化干燥→⊙。

VPI-process: ⊙→pre-baking and to dehumidify→workpiece into the vacuum exhaust tank→vacuum exhaust→vacuum impregnation→pressure impregnation→pressure remove paint→relief pressure, dripping paint→workpiece out the tank→curing baking→⊙.

比较：显然，VPI在漆液渗透方面和浸渍方面，远远优于其它浸漆工艺。在应用方面，VPI更适合大型高压线圈、多层齐绕磁轭线圈和要求较高的大型绕组、以及其它高压线圈。理论上，VPI的应用，真空和压力可以做得相当的高，当然成本也高了。FGH则不然，由于连续作业，以及产量和成本的具体要求，其应用具有一定范围的限制。

Make a comparison: Obviously, the varnish liquid penetration and impregnation of VPI is superior to the other technology. In terms of application, VPI better suits the large-scale high voltage coil, multilayer magnetic yoke coil, demanding large-scale coil and other high voltage coil. In theory, vacuum and pressure can achieve quite high while applying VPI, the cost

is high at the same time. On the contrary, FGH is not the case. Because of the continuous operation and the specific

requirements of production and cost, which limit the range of application.

在应用试验和实际工作中，我们发现，真空环境对于某一温度条件下的一种浸渍漆液，当其真空度低于某一绝对压力的数值时，亦即达到某一对应的“临界”真空时，会导致该浸渍漆液中大量泡沫和液面大量雾气的产生，即发生“沫化”和“雾化”现象。“沫化”造成漆液中大量空穴，会阻碍浸渗。“雾化”致使溶剂或稀释剂大量逸出，会影响固化。In the application testing and actual operation, we found that it exists one kind of varnish liquid under one certain degree in vacuum. When the vacuum degree is lower than the absolute pressure value or up to a certain “critical” vacuum, it will produce a lot of foam and mist in the varnish liquid. This phenomenon is called “foaming” and “nebulization”. “Foaming” will cause a lot of void in varnish liquid and influence the infiltration. “Nebulization” will cause lots of solvent or thinner overflow and influence solidification.

对于压力，原则上加压是为了使漆液更容易进入填充空隙，输漆过程实际上就有一个大气压。如果绝缘结构内毛细管的润湿性已经平衡，则增加压力对整个绝缘结构的填充并无明显作用，除非在固化时一直维持增加的压力，所以，增加填充的有效途径，是降低漆的粘度和减小绝缘结构空隙、提高毛细管效应，而不是提高压力。根据“粘度与压力对渗透速率”的试验，其数据显示：当漆液粘度较大时，增大压力对填充速度有较大作用，在漆液粘度小时，增大压力对填充速度的作用不显着。然