To understand the meaning of the expression circular magnet we must first analize the term magnet: it is an object that has the capacity of generating a magnetic field. The effects of this magnetic field are the movement of ferromagnetic materials and the force of attraction (or repulsion) between two magnets.
By the term "electromagnet" we indicate instead a wire coil in which an electric current may circulate, converting it into a magnet. When the current stops, the magnetic effect also vanishes.
When we speak of circular magnet we usually refer to an electromagnet (not to a permanent magnet), with a simple and robust structure, designed and used for the lifting of ferromagnetic materials. The strongest attraction point in circular magnets is typically the center, where the core is. The circular construction makes this type of electromagnet extremely solid and durable.
There are several types of circular magnets, powered at 12-24-110-220 volt DC. Regardless of the supply voltage, all these magnets have the simplicity of use as a common feature.
The circular magnet is normally used where there are no great precision requirements: it is the case of the scrap lifting. For more sophisticated applications, in which the pieces to be lifted have well-defined and constant shape, or there are specific needs of handling, magnets other than those of cylindrical shape are commonly used, although the circular magnets may sometimes well suit the application.
A dedicated magnet grants usually a better performance, provided that much harder use restrictions are respected. This makes its use more complex and often makes the much more simple and versatile circular magnet being preferred.