The frame linear electromagnet converts electrical energy into mechanical energy. Its movement modes include active travel from the starting position to the ending position (driven by electromagnetic force), as well as passive reset achieved through external forces (such as springs, gravity, or magnetic fields) after power failure. Some designs will implement a "high-power start, low-power steady state" mode through a power controller, which ensures strong thrust during startup and reduces energy consumption and temperature rise during continuous operation. Electromagnets can be installed in any position, but the transmission of force must be axial.
The core of a frame electromagnet is an electromagnet, and its working process follows the typical pattern of monostability:
Generating magnetic force (energization): When the coil is energized, the current generates a magnetic field around the iron core. This magnetic field magnetizes both the fixed iron core and the movable iron core, turning them into "magnets" with opposite polarities.
Drive load (action): Based on the principle of "opposites attract", the movable iron core (also known as the armature) is attracted and moves linearly towards the fixed iron core, thereby driving the load connected to it to complete a pushing or pulling action.
Automatic reset (power-off): Once the coil is powered off, the electromagnetic force disappears instantly. At this time, the reset spring installed inside the electromagnet will come into play, pushing the movable iron core back to its initial position quickly, waiting for the next power-on command.
To help you understand more intuitively, you can refer to its basic structure:
Coil: It is made by winding enameled wire, and generates a magnetic field when electrified, serving as the "power source" of an electromagnet.
Fixed iron core: Integrated with the frame, it is used to conduct and concentrate magnetic flux lines, enhancing magnetic force.
Movable iron core: Also known as the armature, it is the only moving component and is directly connected to the load.
Reset spring: Provides a reset force after power loss to ensure monostable characteristics.
Frame: An open-type metal enclosure in the shape of a "U" or rectangle, which serves as both the mounting framework and a part of the magnetic circuit, and also aids in heat dissipation for the coil.
Thanks to its structure, the frame electromagnet has two significant advantages:
Strong suction and long stroke: Thanks to the efficient magnetic circuit design, it can output a large force in a small volume.
Good heat dissipation: The open structure facilitates the dissipation of heat from the coil, making it suitable for scenarios requiring prolonged power-on or frequent operation.
Its application is very extensive, from vending machines, cash registers, office equipment, to automobiles, toys, medical equipment, etc. For example, when a vending machine dispenses a drink or a cash register ejects a cash box, it may be a small frame electromagnet working behind the scene.
