Electromagnets

Electromagnetic Specifications

Electromagnets are classified as either resistive or superconducting based on the coiling wires used. Dexter’s experience lies in resistive electromagnet technologies.

Electromagnets are comprised of two main elements to produce a magnetic field when powered: the coil(s) and a current source.

Their general purpose is to provide a magnetic force to actuate mechanical components. The field can be manipulated by a change in current, core material, or the number of wire loops.

In contrast to permanent magnets, electromagnets can be switched off and don’t require special rare earth materials. However, sometimes a selection of a unique core material can aid in a higher field output. The three main power setups of electromagnets are Low Frequency AC, DC, and Pulse.

Read our latest whitepaper on Electromagnet Design Considerations here.

Applications

Electromagnets are very widely used in electric and electromechanical devices, including:

• Motors and generators.	• Actuators, such as valves
• Transformers	• MRI Machines
• Relays	• Electric bells and buzzers.
• Loudspeakers and headphones	• Magnetic recording and data storage equipment: tape recorders, VCRs, hard disks

Advantages of Electromagnets over Permanent Magnets

Dynamically controllable field strength
Can be turned off (safety, reduce power consumption)
Can feasibly achieve higher strengths
Assembly of device is safer
Electromagnets don’t risk demagnetization the way permanent magnets do

Advantages of Permanent Magnets

Constantly maintains magnetic field without a drop in strength
Can be lightweight and compact due to higher energy density of magnet material
Can be a cost-effective solution (especially since no power is needed to run/operate)
No maintenance or cooling required as magnets do not produce heat from an energy source