Sealing and IP Ratings for Solenoids and Actuators

Actuator Construction

Solenoids and small actuator devices inherently have movement between parts, which requires a sliding or rolling support that may be susceptible to dust or moisture ingress. In many cases, solenoids also have electrical connections passing through the case of the device that may also be susceptible. Where applications are subject to aggressive environments, some degree of sealing may be required to protect the solenoid against dust or moisture ingress.

IP Ratings

Solenoid coil IP (Ingress Protection) Ratings are used to define the levels of electrical sealing effectiveness against ingress or intrusion of external foreign bodies such as dust and water or moisture. Standard solenoids in general are not rated highly for ingress protection. This requires customization to provide some level of sealing to the solenoid or actuator.

An official IP rating requires a good deal of individual testing of every single part manufactured. This can be very time consuming, and therefore costly. That said, we can usually address any levels of sealing required, without going through the IP Rating without the cost of going through the testing process,

Just let us know what you need, and our engineers will effectively address the level of protection your application needs!

Sealing Options for Solenoids and Actuators   

Sealing of solenoids and actuators usually involves the use of elastomeric components fitted between parts, that conform intimately to the surface of the parts to seal against dust or moisture ingress.

Static seals are fitted between components that do not move relative to one another, while Sliding seals are used to seal against moving parts. It should be noted that sliding seals can add some friction, resulting in a reduction of the developed force or torque, and are also subject to wear. Sliding seals are available in a wide range of sizes and materials.

Bellows seals flex to accommodate movement, enabling in many cases sealing to be achieved without losses in performance. it should be noted that bellows seals may be customized, and consequently may require significant tooling costs.

Where is Sealing Required?

In the case of the solenoid device pictured, a groove is incorporated in the front face for an O-ring seal. This seals against the component to which the solenoid is mounted. There is no seal between the front face and the solenoid shaft, so fluid or dust could enter here when the solenoid is loose as shown. The addition of a sliding seal here would add friction and impair the solenoid’s performance so should be avoided if possible.

When the solenoid is mounted against another component with a seal, provided the back portion (black as shown) is sealed against dust and moisture ingress, the application is sealed. In this case, the cable exit is sealed into the body of the solenoid with resin.

Electrical Termination

An electrical cable exiting a solenoid or actuator may be sealed to the device with an elastomeric sealing grommet, a compression fitting, an adhesive sealant or a combination of these.

Electrical connectors are also available that incorporate elastomeric sealing elements to seal to mating connectors, and to seal to the case of a device.

Potting or Encapsulation

Potting or Encapsulation of electrical coils in a solenoid or actuator can protect these from being affected by dust or water ingress. Even if these do get inside a device, this provides an additional layer of protection for electrical integrity.

In some cases, encapsulation may also protect some of the metal components of the actuator in addition to the electrical coil.

Still have questions? Let us know below; we’re happy to help!