Each finished part was placed through thermal curing and uv inspection before. Vacuum pressure impregnation process, the resin penetrated, final product is cured afterwards in an oven. Air is evacuated from the porosity under dry vacuum and a liquid sealant is drawn into the porosity, filling any voids and leak paths. The dvp cycle requires two separate tanks, one for processing the part and the other for storing the sealant.
Vacuum pressure impregnation process in superconducting coils. The drying process typically consists of following steps 3 a preparation b heating and drying c pressure reduction d fine vacuum figure 2 shows the sequence of operation of vacuum phase drying in a vacuum vessel and the four typical stages of vapor phase of drying process. Drytype transformers can be categorized into good, better, and best classifications. Our vpi systems can be used for applications such as coating, sealing and insulating porous parts. Heattek, inc offers vacuum pressure impregnation vpi systems ranging in size from 20 to 120 in diameter. Vacuum impregnation seals porosity and leak paths that form during the casting or molding process. Hello, i will try to explain in laymans language and to the extent i know. How to decide if vacuum impregnation or vacuum pressure. As a custom transformer manufacturer, we stand out in the crowd by providing.
Us3979530a polyester fibervacuum impregnated epoxy. Vacuum impregnation and vacuum pressure impregnation is used for the processing of a range of electrical components, where a full penetration of impregnating resin must be guaranteed. Vacuum pressure impregnation machines hull industries. All plant is available with fully automated process control based on industrial plc or pcplc systems. Production, such as vacuum drying, vacuum distillation, vacuum drying, vacuum coating and so on. I is a process by which a fully wound electric apparatus stator or rotor is completely submerged in a resin. Transformers are placed in the vacuum chamber and a vacuum pulled to a minimum of two torr and held for 20 minutes. The process is used primarily for highvoltage motors and generators to fill gaps in materials to create a void free insulation in various devices. Double vacuum process a process used particularly for the impregnation of dry timbers that must retain dimensional accuracy for use in class 3 as windows and door frames, etc. Hering has specialized in improving the life cycle of transformers. For this type of work, epoxy resins are used, due to their low viscosity and low vapour pressure. The resin is then allowed to flow into the chamber until the transformers are completely covered.
For nonporous impregnation of most different components, insulating media such as varnishes, oils, resins and waxes are used. Our reputation for excellent quality and service is wellknown in the industry, and sets us apart from the competition. Imprex is the leader in vacuum pressure impregnation from manufacturing vpi equipment to inhouse impregnation of castings, powdered metal parts, and electronic components. For processing of motors, generators and transformers. It is the preferred method for preventing fluids or gases from leaking under pressure.
The main purpose of vacuum impregnating transformer coils is to remove as much air as possible from the structure and replace it with epoxy which has significantly better dielectric strength. This system strengthens the insulation system and extends the service life of the transformer. The impregnation stage is the first part of the porosity sealing process. Ssv01 varnish vacuum pressure impregnation machine youtube.
Vapor phase drying for moisture removal from transformer coil insulation mohd. The vacuum pressure impregnation vpi techniquea particularly refined case of the more widely known vacuum assisted resin transfer mould vartmhas become the most common process for the. This vacuum impregnation system has an impregnation chamber of size 500mm diameter x 650mm height and an effective loading depth of 500mm with detachable torispherical dished end on both the side of the chamber. They are suitable for coil varnish treatment of drytype transformers with dupont nomex paper insulation and drytype transformers of the mora company in germany production needs. For applications such as large motors and generators, high voltage transformers, special transformers, etc.
The singlephase and threephase insulation transformers are equipped with either copper or aluminum windings. Heattek, inc offers a complete line of vacuum pressure impregnation and dip tank systems. Provided that the transformer tank is vacuum tight, the drying process can be optimized by. Design and analysis of impregnation chamber used in vacuum. Vacuum pressure impregnation vpi avonmore electrical.
Impregnating resins for electrical applications elantas. Vacuum impregnated, as well as a variety of related products and services. Optional construction features include quickopening covers, and counterweighted or hydraulically raised covers. Vacuum pressure impregnation or vpi treatment is performed on electrical equipments like motors to increase the insulation life and heat dissipation. Vacuum impregnation is used in many different manufacturing processes to enhance mechanical strength, seal surfaces and to enhance electrical insulation properties. Advanced vacuum pressure impregnation vpi system ametek. Vacuum pressure impregnation process in superconducting. Vacuum pressure impregnation vpi is a process in which a wound resinpoor winding is completely submerged in a resin. Insulation comparison vpi produced versus resin rich. Vacuumtested chambers and tanks may be round or rectangular, and can be built to asme code for full vacuum and up to 200 psig pressure. Product brochure vpi vacuum pressure impregnation drytype transformer. If the operator knows the weight of the insulation and the moisture content at start, then the quality of moisture to be removed and be determined and measure.
Welcome to the premier industrial source for transformers. Vacuum impregnation prevents migration of fluids or gas under pressure from contained areas more simply put vacuum impregnation stops leaks. Vacuum impregnating tips steps in coil impregnation. Welcome back to the power magnetics institute, my friends. A brief description of the vpi process that sci follows in the manufacture of its transformers is as follows. Over the years the process has not remained efficient in terms of energy and effectiveness. This is mainly used for porous materials such as ceramics and sprayed coatings, thus reinforcing fragile materials. Through a combination of dry and wet vacuum and pressure cycles, the resin is absorbed into the semiporous insulation to result in a completed winding that is theoretically void free. Our customers have been asking for a clarification of the vpi and plate transformers post we discussed earlier. Jul 15, 2015 vacuum pressure impregnation equipment made in taiwan, all in one excellent sealing and plc auxiliary operation. The range includes plant for processing solid type paper insulated power cables, oil or gas filled cables, paper insulated and coaxial type telecom cables and for predrying and pre impregnation of cable papers. Use of vacuum impregnation in food salting process. Vacuum pressure impregnation equipment for chokes and transformers toroidal solutions to replace ei cores classic transformers and chokes toroidal transformers and inductances property.
The mechanism can be manual or hydraulically actuated. This method involves applying tapes, that are also constructed from. Impregnating the entire unit provides a strong mechanical bond and offers protection from environmental conditions. The vpi process is the most advanced system in use today. It may be simple dipping, roll impregnation rotating in impregnating varnish for 1 21 hr or vacuum pressure impregnation vpi. Vacuum pressure impregnation vpi is the process of treating the finished coils with varnish by placing it a vacuum chamber. Vacuum tested chambers and tanks may be round or rectangular, and can be built to asme code for full vacuum and up to 200 psig pressure. In general, all vacuum impregnation process types follow the same four steps. Vacuum impregnation and vacuum pressure impregnation is used for the processing of a. Acutran transformers is a veteranowned drytype transformer manufacturing and custom transformer design company. Vacuum impregnation stops casting porosity and allows manufacturers to use parts that would otherwise be scrapped. Find your vacuum impregnation transformer easily amongst the 89 products from the leading brands ge.
Whether your company uses a singlebar or a global impregnation process, we assist you in selecting the most appropriate resin for your application, equipment and expected. The vacuum pressure impregnation vpi techniquea particularly refined case of the more widely known vacuum assisted resin transfer mould vartmhas become the. Vacuum impregnation in metal castings and powdered metal parts refers to the sealing of leaks resulting from porosity. The ultimate goal of vacuum impregnation is to seal leak paths and porosity without impacting the functional, assembly and appearance of the part. The process which had explicit porosity impregnation requirements was to be performed on specific areas which required an air tight seal on the pump and oil side of the casting. Since 1958, imprex has supplied custom vacuum impregnation equipment to some of the largest companies. The vpi cast coating system one of the most common application for impregnating compounds is in electrical transformer manufacturing. Vacuum pumps for vacuumpressure impregnation systems. The companies featured in the following listing offer a comprehensive range of transformers.
Impregnation resins and varnishes 3 vacuum pressure impregnation is a leading process for the handling of resin in traction motors, highvoltage motors and generators. The right transformer drying solution provides a low process time, but also protects the equipment from high internal stresses. No reason for old units to take longer time for impregnation reverse could be true. In this post, we will discuss in detail one of the selection variables, the three different types of vacuum impregnation processes. A white paper jonathan lerner mitchell electronics. For vacuum impregnation a component is vacuum treated. Resin impregnation also addresses the inherent defects in parts prior to plating. Resin is then introduced until the component is fully covered by resin.
Multiple heaters immersed into the oil in the chamber enable to heat the oil up to 150c. Large range of vacuum pressure impregnation systems from small systems to very large vpi plants latest technology used excellent value varnish also supplied for first fill different automation levels available vacuum impregnation vi available without pressure. Vacuum impregnation plant vacuum pressure impregnation vpi is a. It is desirable that the spaces between the coverings and the turns of the electrical winding be thoroughly impregnated and coated with the varnish and the varnish coating is then thoroughly cured to provide optimum insulating and thermal conducting properties as. Vacuumpressure impregnation process vpi vacuum pressure impregnation is a process that uses vacuum and pressure to seal voids in various parts, devices, or materials including porosity in castings that may need to be used in a leak tight service or need a smooth uniform surface for improved machinability, and electrical windings of motors. It is widely used in the process of generating vacuum conditions for various equipment, in the production, installation and maintenance of power transformers, capacitors and many other power equipment, as well as in the process of industrial technology. Vapor phase drying for moisture removal from transformer. The purpose of the impregnation process is to completely fill the porosity of a component with a sealant that when solidified is permanent, durable and suitable for the field of use.
Vacuum broken and pressure 75psi applied for 45 minutes. This is the most complex and effective method of impregnation. Vacuum pressure impregnation system at best price in india. Vpi is a well proven process and systems are supplied for all sectors of the electrical and electronic industries.
Impregnation under vacuum using various resins and varnishes is the best solution for this purpose. Vacuum impregnated transformers are available with 2. Optimum equipment solutions for vacuum pressure impregnation. A vacuum tight vessel with boltclamp or boltless quick clamping flanges can be provided. Use of vacuum impregnation in food salting process request pdf. Dry vacuum pressure impregnation system ask price dry vacuumpressure dvp. Hull impregnators incorporate a welded flange to improve sealing quality for use at higher vacuum. Transformer oil purification filtration processprocedure. In addition, epoxies are excellent adhesives and will solidly bond the wires and other components of the structure to form a strong, solid assembly.
The manufacturing process of high voltage power transformers consists of several phases such as design. Sci manufactures all of its transformers using the vacuum pressure impregnation vpi process. Vacuum impregnation and vacuum pressure impregnation is used for the processing of a range of. Us3979530a us05461,071 us46107174a us3979530a us 3979530 a us3979530 a us 3979530a us 46107174 a us46107174 a us 46107174a us 3979530 a us3979530 a us 3979530a authority us united states prior art keywords resin material less impregnated pressure prior art date 19740415 legal status the legal status is an assumption and is not a legal conclusion. Why does one want to apply varnish on transformers. Understanding the vacuum impregnation process ultraseal us. Gehangvpi series vacuumpressure impregnation plant are mainly used in varnish treatment of hclass drytype transformers. In this article you will understand transformer oil purification process, steps and methods involved in oil purification process. Vacuum pressure impregnation vpi systems heattek, inc offers vacuum pressure impregnation vpi systems ranging in size from 20 to 120 in diameter.
This impregnation equipment is typically used throughout the oem electric motor and generator industry, oem transformer industry as well as the electric motor repair industry in order to seal andor coat porous parts without negatively affecting the. All hps control transformers are vacuum impregnated with vt polyester resin and oven cured which seals the surface and eliminates moisture. Impregnation process the vacuum impregnation process is governed by us milstd276a as well as numerous proprietary and customer specifications. Vacuum impregnation vi is a cheaper alternative to full vacuum pressure impregnation, and is suitable for low voltage ac windings, transformers and dc motor windings. Vacuum pressure impregnation equipment for chokes and.
Vapor phase drying for moisture removal from transformer coil. Hedrich designs and builds optimum equipment solutions for vacuum pressure impregnation individually adapted to your requirements. Table 1 vacuum hold time suggest retaining the existing vacuum hold time guideline in c57. Transformer oil purification is a process to remove sludge, dissolved moisture and dissolved gases from the oil. Dry nitrogen blanket injected to lower vacuum to 21 hg. A maximum insulation temperature of 150oc is recommended. Vacuum pressure impregnation vpi is a process that uses vacuum and pressure to seal porous materials with varnish or resin.
Vpi vacuum pressure impregnation drytype transformer. Vacuum pumps for vacuumpressure impregnation systems vacuum. Fig 1 impregnation mold lifting out of the vat fig 2 example of development vpi facility the second manufacturing method is referred to as resin rich technology. Feb 21, 2016 varnish impregnation machine,transformer insulation process,motor insulation process,winding insulation process,coil insulation process,transformer varnish impregnation. This starts during the transformer manufacturing process. Vpi vacuum pressure impregnation is a process that uses vacuum and.
Custom manufacturer of vacuum impregnated power transformers for printed circuit applications. These units feature airtype cooling and can perform up to 2000 kva, with a frequency up to a maximum of. Request pdf use of vacuum impregnation in food salting process salting is an ancient preservation method, usually used separately or in combination with other processes such as air drying and. Typical applications are electromagnetic coils, small transformers, instrument transformers, chokes, sintered bushes and similar products. The process coil assembly baked 2 hours at 375 c to remove moisture. Vacuum pressure impregnation vpi is the process of treating the finished coils with varnish by placing it. Vacuum pressure impregnation equipment made in taiwan, all in one excellent sealing and plc auxiliary operation. However, other ranges such as constructional timber, cladding boards, wooden balconies, etc. The completed formed wound stator is then heated to remove trapped moisture and finally impregnated in varnish class f or h as required. Accurate designing and production are two most essential factors that make any company.
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