Electro-permanent magnetic lifters counteract the limitations of permanent electromagnets and by combining the advantages of both.
The restricted lifting capacity of permanent magnetic lifts and the flawless operation of electromagnetic lifts are two limitations of this type of lifter. To overcome these limitations, lifting magnet designers have created the electro-permanent magnetic lifter, which combines the advantages of both electromagnetic and permanent lifters in a single module.
Types of magnets
There are three types of magnetic lift technologies: permanent magnetic, electromagnetic, and electro-permanent magnets. Permanent lifting magnets use fail-safe permanent magnets, but they do not have a variable holding power capacity, which restricts both their load capacity and the variety of applications for which they are best suited.
Electromagnetic lifters use a driver to generate a DC voltage in a coil embedded within the elevator module to generate the holding force of magnetic work. The voltage of the DC controller can be adjusted to vary the magnetic flux field, which, in turn, varies the clamping force of the electromagnetic lift. This characteristic makes electromagnetic lifters flexible and also very cost-effective clamping devices. But electromagnetic elevators require continuous electrical power to function. A power outage will de-energize the electromagnet, turn off the magnetic field, and create a potential safety hazard. Electro-permanent magnetic lifters counteract these limitations.
Electro-permanent lift operation
Electropermanent magnetic lifters (commonly called electroperms) are a hybrid of the permanent and electromagnetic types. They are built with a coil wound around a magnetic material that is permanent, embedded in the lift module. When a DC voltage is applied, the material charges, which takes about 1 second, and draws the material to the lifter even after the power is cut off. The lifter will hold the load until the electro-permanent magnet turns off. This characteristic gives electroperms a fail-safe operation.
Another function of the electroperm coil is to control the amount of magnetic force from the lifter. This feature gives it a variable holding power capacity similar to electromagnetic hoists. This feature broadens the types of applications for which the electroperm is suitable. Electroperms can be used in tandem for beam lifting operations, as well as light load, pick and place robotic operations. For pick and place operations, the electroperm is modified to be lightweight to maximize arm end capacity. They are built with special coil configurations for fast switching with minimal dwell times and contoured soft pole shoes to provide the easiest part access.
Battery operation
Electro-permanent magnetic lifters are sometimes called battery lifts because a battery is used instead of a DC controller to provide the power for the electroperm switching cycle. The battery gives the lifter portability. It also makes system design simpler because a complex DC controller is not necessary. However, the battery will require regular maintenance and charging.