Coil Impregnation

Impregnating transformer coils improves dielectric strength and helps reduce rattle and hum in transformers.

If you are considering use of an epoxy for your transformer applications, low viscosity options with good dielectric, mechanical and thermal properties are available to you through Multimarket.

Electrical Transformer Manufacturing: 

A common application for epoxy potting and encapsulating materials is coil impregnation in electrical transformer manufacturing.

Transformer coils are encapsulated for a variety of reasons including:

• Increasing dielectric strength
• Improving the structural integrity of the coil
• Reducing or eliminate winding noise
• Improving heat transfer
• Reducing partial discharge
• Providing increased environmental protection

Why use epoxy when needing to encapsulate coil windings in transformers? Epoxy potting and encapsulating compounds offer the best combination of adhesive strength and noise dampening capability. Furthermore, epoxy systems are also easily modified for viscosity reduction, thermal conductivity, and a variety of curing options. As a result, epoxy systems in combination with vacuum impregnation is a common choice for encapsulating coils. In these situations a vacuum is utilized to remove as much air as possible and replace it with epoxy.

What to look for in an epoxy for encapsulating tightly wound transformer coils? The ideal option is often a low viscosity epoxy. The types of epoxy potting compounds can vary depending on the size and type of coil however some properties that are generally always needed are low mixed viscosity, good dielectric strength, high bond strength, high operating temperature, and good sound dampening. Low exothermic, long pot life two component systems containing special fillers, modifiers, pigments can be automatically dispensed through meter mix equipment and cured at low temperatures while preventing any air bubble formation, pin holes, imperfections, cavities.

For fully automatic vacuum casting systems in high-volume production of ignition coils, a viscosity stable epoxy is key so the perfect amount is filled each time.

What does Multimarket have to offer?

EC-1850FT is a liquid-dispensed filled epoxy system offering excellent heat transfer, high voltage insulation, low exothermic and minimum shrinkage. It is a lower viscosity version of EC-1850FT-LV. It rapidly transfers heat, eliminates hot spot, and increases the operating efficiency of most encapsulated devices. Its low shrinkage minimizes risk of damage to fragile components. It is useful for potting and encapsulating densely packaged power supplies and heat generating components, integrated circuits, power and operational amplifiers, transformers and many types of semiconductors.

EC-1015 is a low viscosity liquid-dispensed epoxy resin system featuring high thermal conductivity, good electrical insulation, and low shrinkage during cure. It is useful for potting and encapsulating densely packaged electrical applications.

EC-1012M is a pourable, flame retardant, filled epoxy resin system featuring high thermal conductivity, good electrical insulation and low shrinkage during cure. It is useful for potting and encapsulating components or modules, when removal of heat and resistance to mechanical and thermal shock are prime considerations. Typical Applications include potting or encapsulating densely packaged power supplies, integrated circuits, small transformers, capacitors bushings etc.

EC-1015LV-RT is a low viscosity filled epoxy resin system featuring high thermal conductivity, good electrical insulation, and low shrinkage during cure. It offers the excellent heat transfer, high voltage insulation and dimensional stability over a wide temperature range. As an encapsulant for power devices it distributes heat evenly throughout the casting, providing greater efficiency and longer working life. It is useful for potting and encapsulating densely packaged power supplies, integrated circuits, thick film hybrid devices, D/A converters, oscillators, amplifiers, relays, transformers and semiconductors etc

Available through Multimarket, these and other products are offered in bulk containers for automated production, and in easy to use dual cartridges for production by hand and for prototyping purposes. Easy to use, there is no need to weigh or mix the epoxy by hand. Do get in touch for pricing and availability.