مبدأ عمل ملف لولبي دوار electromagnet is based on the principle of electromagnetic attraction. The electromagnetic attraction generated by the current-carrying iron core coil is used to manipulate the mechanical device to complete the expected action. When the coil is energized, the iron core and the armature are magnetized and become two magnets with opposite polarities, generating electromagnetic attraction between them. When the attraction is greater than the reaction force of the spring, the armature begins to move toward the iron core. When the current in the coil is less than a certain value or the power supply is interrupted, the electromagnetic attraction is less than the reaction force of the spring, and the armature will return to the original release position under the action of the reaction force. The specific process is as follows:

1.1.1- Magnetic field generation: When current passes through the stator coil, a magnetic field is generated around the coil. The direction of the magnetic field is determined by the direction of the current (following the right-hand rule).

1.1.2- Interaction between the magnetic field and the rotor: If the rotor is a permanent magnet, it will be subject to the force of the stator magnetic field and try to align with the stator magnetic field. If the rotor is a ferromagnetic material, it will be magnetized and subject to attraction or repulsion in the magnetic field.

1.1.3-Generation of rotational torque: By cleverly designing the arrangement of the stator coils and the direction of the current, the direction of the stator magnetic field can be continuously changed. The rotor is subjected to a continuous torque in the changing magnetic field, and thus begins to rotate.

1.1.4-Commutation and continuous rotation: In a DC motor, the commutator and brushes are used to switch the direction of the current to ensure that the rotor is always subjected to a driving torque during the rotation process, thereby maintaining continuous rotation. In an AC motor, the alternating current in the stator coil automatically generates a rotating magnetic field, driving the rotor to rotate.