AC Electromagnet for Aluminum and Copper
While shaded pole solenoids are not typically designed for attracting non-ferrous metals like aluminum or copper, they can exhibit a weak attractive force under specific circumstances. Here's why:
Eddy Currents: When an AC current passes through the coil of the shaded pole solenoid, it creates a changing magnetic field. This changing field induces eddy currents in nearby conductors like aluminum or copper.
Lenz's Law: According to Lenz's Law, these eddy currents create their own magnetic field that opposes the original field from the solenoid. However, due to the shading ring in the solenoid design, the opposing field is not perfectly uniform and differs in phase.
Uneven Force: This unevenness in the opposing field can result in a net force, though weak, that partially aligns with the original field from the solenoid. This partial alignment can cause a slight attraction towards the solenoid.
It's important to note that:
The attractive force for non-ferrous metals is significantly weaker compared to the force exerted on ferrous materials (like iron, steel) that are directly attracted due to their inherent magnetic properties.
This effect is highly dependent on the specific design of the solenoid, the material properties of the conductor, and the operating conditions (frequency, current).
Therefore, while shaded pole solenoids can exhibit a weak attractive force towards aluminum or copper under specific conditions, it's not their intended purpose, and the force is significantly weaker compared to their interaction with ferrous materials.
Shaded Pole Relay:
Function: An electromagnetic switch used for low-power applications.
Operating principle: Utilizes an AC coil with a shading ring (also called a shading coil). When energized, the coil creates a magnetic field. The shading ring disrupts this field, creating a phase shift that keeps the relay engaged even when the current in the coil goes to zero during the AC cycle. This prevents the relay from constantly "chattering" on and off.
Applications: Commonly used in appliances like refrigerators, fans, and timers due to their simple design and low power consumption.
