An electric coil comprises two distinct components: a conductor and a core. The conductor is typically made of solid copper wire wrapped around a metal core. A turn is created each time the wire is looped around the core, while multiple turns are considered a coil. It acts as an electrical conductor, efficiently sending an electrical current to generators, electric motors, electromagnets, and inductors.
The most common application of an electric coil is as an inductor, which stores energy within its electric field. As a passive electronic component, an inductor has no gain and thus cannot control the directional flow of energy. Instead, it captures energy from the electric current flowing through its body.
Electrical coils are typically required in industrial manufacturing, medical equipment, and devices used to supply electricity to commercial and residential buildings.
Definition of an Encapsulated or Potted Coil
Like any other electrical coil, an encapsulated or potted coil is constructed from a ferromagnetic metal wire wrapped into a specific diameter. It is an electromagnet that is only activated by magnetism when exposed to electric currents. Since most coils use outer casings for protection from harsh environmental conditions — such as salt, water, moisture, and vibration — encapsulated coils are frequently molded into liquid or thermoformed epoxies. This procedure causes the coil to fuse with its casing.
Both encapsulated and potted coils surround and seal the coil with liquid materials, including silicone rubber, epoxies, and polyesters. These materials are available in temperatures ranging from 105 °C to 190 °C. The only difference between the processes for encapsulated and potted coils is the tooling: encapsulation utilizes a reusable mold into which the coil is placed, filled with material, and then removed after curing. Meanwhile, potting uses a single-use cup, which soon becomes a component of the final product.
Advantages of Using Encapsulated or Potted Coils
Encapsulated or potted coils have high dielectric and isolation properties and uniform dimensional and cosmetic characteristics. Thus, they often provide better protection against extreme environmental conditions than molded coils. Besides that, because they are dipped and thermoformed into sealing liquid, epoxies such as silicone rubber provide vibration protection that molded casings do not. Encapsulated coils can also be heat-treated after manufacturing, which sinters the plastic component with the molded coil inside, providing excellent protection.
Moreover, encapsulation and potting processes aid in transferring heat and protect the components from thermal shock and adverse working environments, such as grease, salt, water, humidity, and gasoline. Finally, they provide a cost-effective alternative to overmolding when a protective outer shell is required, as overmolding tooling can be costly and impractical in small volumes.
Endicott Coil Company’s Encapsulated Coil Manufacturing
Endicott Coil Company creates customized encapsulated coils resistant to the harshest environmental circumstances. Depending on the customer’s application, our experts select the best encapsulation material, such as thermoplastics, thermosets, epoxies, silicone rubber, and polyesters.
We are fully equipped with vacuum chambers, vacuum ovens, and curing ovens to achieve a proper cure regardless of the material used.
Our company produces encapsulated coils with temperatures ranging from 105 °C to 240 °C. To ensure that all specifications are met, these coils are extensively tested using hi-pot, inductance, resistance, leak, and surge testing.
High-Quality Custom Coils and Components From Endicott Coil Company
Endicott Coil Company, Inc. has a long history of providing high-quality custom magnetic components and services. Our company leverages our extensive knowledge, expertise, versatility, and capabilities to meet and fulfill each customer’s specifications. We also offer comprehensive value-added services — such as overmolding, encapsulation, and sub-assembly manufacturing — in addition to our wide assortment of coils and transformers.
Our facility is RoHS compliant and employs ISO methodologies and procedures throughout the manufacturing process. Furthermore, we have experience with ASTM, CSA, VDE, NRC, Mil-Spec, and UL testing procedures.