Electromagnets

Electromagnets are magnets powered by electricity, creating controllable magnetic fields, and the strength of magnetic field depends upon main factors such as number of turns of the wire, the current intensity, as well as the core material. Electromagnets are widely used as components of electrical devices, such as motors, generators, electromechanical solenoids, relays, loudspeakers, hard disks, MRI & MRT machines, Magnetic Levitation (Maglev), scientific instruments, lifting & holding, and magnetic separation equipment.

Description

Electromagnets usually consist of core (either solid or laminated), coil, yoke (optional), housing, terminals, circuit controller and source of power, and they will start to produce magnetic fields when electric currents flow through coils made of hollow conductors or wires. The working principle depends on the relationship between electric currents and magnetic fields, and the strength of the magnetic field can be controlled by adjusting the electric current. As you might be aware that there are many ways to categorize electromagnets. One way is to classify by the type of power source, DC, AC, and pulsed power, and the another way is to classify by the type of coil wires. Electromagnets have big family members below:

• √ Resistant Electromagnets
• √ Superconducting Electromagnets
• √ Hybrid Electromagnets
• √ Solenoid Electromagnets
• √ Toroidal Electromagnets
• √ Plunger Electromagnets
• √ Lifting Electromagnets
• √ Rotary electromagnets

Fabmann supply large electromagnets weighing from few kilograms to few tons, and our coils are mainly made of hollow conductor, copper strip and wire wound coils. We are highly focusing on custom design for prototype magnets to volume production, we are capable of handling the most sophisticate magnets. To make high precision electromagnets, it requires great experience and in-depth knowledge of the entire manufacturing process. Plus, all critical components are manufactured at our own facility to maintain the tight tolerance required. Fabmann is committed to providing custom electromagnets for proton therapy, particle accelerator research and development, nuclear physics, aerospace, nuclear medicine and other scientific fields, and our customized electromagnets include RFQ, DTL, IH-Buncher, high frequency vacuum chamber, giggle undulator, and proton linac.

Design Consideration

The design is driven by the application, and therefore, all aspects shall be taken into consideration, and Fabmann engineering team always focuses on the following:

• √ Core permeability, it is a crucial property of the core material as it affects the strength of the magnetic field generated by the electromagnet. It is worth noting that high relative permeability material cores do not suit all applications. In fact, the strongest electromagnets, like superconducting electromagnets and pulsed electromagnets, with very high electric current do not use iron cores.
• √ Nonlinearity and saturation, they are important properties of magnetic materials that affect the behavior of electromagnets. The nonlinearity of magnetic materials is exploited in devices such as transformers and inductors, where it allows for the storage and release of magnetic energy. Saturation is used in applications such as magnetic recording, where it provides a way to store information in the form of magnetic domains.
• √ Residual field and mitigation, it can cause the electromagnet to require more energy to reach the desired magnetic field strength, reducing its efficiency. It can also cause hysteresis losses, which are energy losses due to the nonlinearity of the magnetic material. Further more, it can cause interference, in applications like magnetic recording and medical imaging, residual field can interfere with the reading and writing of data or distort images.
• √ Ringing, it can lead to higher power consumption due to the energy dissipated in the oscillations, and the oscillating magnetic field generated by ringing can interfere with other electronic devices nearby. High-amplitude ringing can cause damage to the electromagnet's components, such as the coil insulation or the switching devices. Further more it can reduce the overall efficiency of the electromagnet by causing energy losses and instability.
• √ Magnetic annealing, it is a heat treatment process that improves the magnetic properties of ferromagnetic materials, such as iron and steel, and the process is designed to heat the material to a high temperature above its Curie point, where it loses its ferromagnetic properties, and then slowly cooling it down in a controlled magnetic field. This process aligns the magnetic domains within the material, resulting in improved magnetic properties.
• √ Uniform field, A uniform magnetic field usually means the amplitude and vector direction of the magnetic flux density are nearly the same across a volume of interest. In practice, a magnetic design engineer examines the distribution range of the main field components – Bx,By, or, Bz in Cartesian coordinate system – in the volume of interest to assess field
• uniformity.
• √ Efficiency, a good electromagnet design means high efficiency, and the benefits of efficient magnetic designs are multifaceted. It include linear region operation, minimizing magnetic reluctance, minimizing loss, uniform distribution of magnetic flux, pulse width and amplitude
• √ Instability: In magnetic levitation systems, residual field can affect the stability of the levitated object.
• √ Working aperture, the working air gap between the poles, which may include the required size of the beam clear area, the thickness of the vacuum chamber, and the installation air gap.
• √ Center magnetic field strength
• √ Magnetic length
• √ The scope of the useful field area, which refers to the space required for the beam clear area in the magnet
• √ Discreteness of the magnetic field between magnets, which refers to the root mean square deviation of the integrated magnetic field discreteness between each similar magnet
• √ The operating state of the magnet, whether the magnet excitation is DC or pulsating
• √ Space size restrictions
• √ Safety

Customized Electromagnets

Concept and design is very powerful if it’s backed up by solid experience, our in-house design team is highly integrated with both production team and lab testing, and our team has solid experience in validating your models before making quotation. Due to this special capacity, we can make current choice for you regarding manufacturability, efficiency and repeatability, from the first stages of design to finished products. Fabmann works with various top notch material suppliers to develop customized electromagnet, and our engineers and designers can create solutions tailored to your specific application needs. Our product engineering team will make careful analysis of your application demand, and then select the appropriate materials, fabrication techniques, assembly solution and validation testing process for achieving superior performance, efficiency, and reliability compared to off-the-shelf options. Our mission is to deliver high precision customized electromagnets for demanding applications where precise control and optimized performance are critical. Our electromagnet family members are:

Dipole Electromagnet

Quadrupole Electromagnet

Sextupole Magnet

Octupole Magnet

Solenoid electromagnet

Scanning Magnet

Corrector Magnet

Kicker Magnet

Septum Eletromagnet

Wiggler and Undulato

Custom Electromagnet

 

Production Process

Electromagnet production is a very sophisticated manufacturing process, and Fabmann is dedicated in the research and development, manufacturing and assembly of particle accelerator equipment which includes various types of electromagnets, coils, RFQ, DTL, Buncher, undulators, beamline experimental equipment terminals.

Production Equipment

Fabmann is working with top electromagnet specialist, and we have the following production facility as in-house.

• √ Hydraulic stamping machine
• √ Five-axis machining center,
• √ Three-axis machining center
• √ CNC lathe machine
• √ Argon arc welding machine, gas shielded welding machine, welding robot
• √ Laser and plasma cutting equipment
• √ Medium-speed wire cutting machine & high-speed wire cutting machine
• √ Vacuum brazing furnaces and hydrogen shielded brazing furnace
• √ Vacuum casting furnace
• √ Vacuum machine
• √ Heating and curing furnaces
• √ Vertical and horizontal winding machines, and 3D winding machine, precision winding machine, superconducting winding machine
• √ Ultrasonic cleaning machine
• √ Industrial water coolers with a cooling power of 66kw

Production Process

Electromagnets are designed to use electric current to generate magnetic field, and the production process includes few steps and each step consists of sub-steps. To make a sound production each electromagnet will go through sophisticate production process as well as comprehensive tests both on component and the fully assembled product. Below is a production process for a typical dipole or quadrupole magnets.

√ Understanding the design and function requirement, and our engineers will do full analysis of your requirement before material selection.

√ Quantify technical requirement such as magnetic field strength, temperature rise, air gap, nominal resistance, power consumption, max instantaneous power, physical dimension, weight.

√ Material preparation based upon desired magnetic field strength and size, and this will dictate the type and amount of materials needed. This part is critical for making good quality magnets, and it decides how to choose the following key component materials:

• 1. The core material shall be made of iron, steel, or other ferromagnetic materials because it can enhance the magnetic field strength, confining magnetic flux, reducing reluctance, providing mechanical support, and facilitate dissipating heat in electromagnets. Therefore, choosing the right core material and design is crucial for optimizing the performance and efficiency of electromagnets for desired applications.
• 2. The wire gauge and type or the hollow conductor type and dimension because the dimension determines the amount of current the coil can handle, and the wire type (copper, aluminum, etc.) affects its conductivity, resistance and heat dissipation.

√ Coil winding & insulation, it is the fundamental component of an electromagnet, responsible for generating and controlling the magnetic field in terms of magnetic field direction and field strength.

√ Assembly, secure the coil to the core, and the coil should be firmly attached to the core to prevent movement and ensure optimal magnetic field generation. In addition, the assembly of the shell is required to protect the coil and the core, and to facilitate the use and installation of the electromagnet.

√ Testing and calibration, measure the magnetic field strength and ensure it meets the desired specifications, and this process is critical to exam all the desired specifications are achieved, and therefore extra attention shall be paid to factors like insulation resistance voltage resistance, inductance, temperature rise.

In summary, the production process of the electromagnet includes material selection, preparation, assembly and testing. Through appropriate process flow and strict quality control, electromagnet products with stable performance and reliable quality can be achieved.

Testing Facility

• √ Point measurement equipment
• √ Rotation measurement equipment
• √ Vertical measurement machine with DC power supply
• √ Three-coordinate measuring instrument
• √ Six-axis three-coordinate measuring machine
• √ Vacuum leak detection equipment, helium mass spectrometer leak detectors
• √ High-frequency test equipment, network analyzer
• √ Ultrasonic flaw detector
• √ Magnetic permeability measuring instrument
• √ Roughness measuring meter
• √ Turn-to-turn voltage tester
• √ Winding turn-to-turn impulse voltage tester
• √ Power frequency voltage tester

Quality Control

Electromagnet testing is a critical control process to verify whether its function meets the original design. Since the production involves more than ten different production solutions, and the relevant testing is required to verify whether each production process is qualified. We all know that the quality of an electromagnet is judged by its magnetic strength, performance and durability, and meanwhile, appearance, coil quality, and electrical performance of the electromagnet are also important factors in measuring its quality. A good electromagnet should withstand extensive test load, and it will not be prone to magnetic decay or performance degradation, and the durability of the electromagnet can be predicted by examining the material composition and manufacturing process of the electromagnet. In addition, the core and coil are important components, and therefore thorough check on core and coil is critical part of evaluation of electromagnet quality.

To verify the production quality, Fabmann will go through over 15 different testing parameters for each custom made electromagnet, and below is the summary of what tests are carried out before delivery:

• √ Visual inspection
• √ Dimension check
• √ Conductor resistance detection
• √ In-Turn short circuit test
• √ Dimension, electrical and mechanical check on hollow conductor before coiling
• √ Water flow rate measurement
• √ Water pressure drop test
• √ Insulation resistance check
• √ Voltage resistance detection
• √ Inductance measurement
• √ Thermal switch check
• √ Temperature rise check on core
• √ Temperature rise check on coil
• √ Magnetic polarity check
• √ Magnetic field detection
• √ Key component measurement check (three coordinate measure)

Visual Inspection

Dimension Check

Electrical Resistance Test

Turn to Turn Voltage Test

Mechanical Test of Hollow Conductor

Water Pressure Check

Inductance Check

Voltage Resistance Test

Thermal Switch Check

Magnetic Polarity Check

Magnetic Field Detection

Three Coordinate Measuring

Pulse Turn to Turn Test

Insulation Resistance Test

Core and Coil Temperature Rise Check

Professional Project Management

Custom electromagnets are very demanding products which require special field of expertise, and we specialize in custom electromagnets designed and produced as per customers’ requirements. Whenever a special size, magnetic field or force, higher heat resistance is required, Fabmann can help you design and manufacture according to your requirements. Customization really requires quite comprehensive parameters:

• √ Power & holding force including heat affects
• √ Force over gap (between electromagnet and ferromagnetic work piece)
• √ Impact on work surfaces
• √ Heat & environmental management, ohmic heating because of the resistance of the windings
• √ Special dimension to match customer’s application
• √ Precise field, special magnetic curve
• √ Materials

Fabmann Project Management

Our custom fabrication service includes following procedures:

• √ Initial consultation, Fabmann takes a collaborative approach to work with your team to achieve a thorough understanding of your design requirements.
• √ Design and engineering, based on your desired performance criteria, our team will select the most suitable materials, design for manufacturability, and create thermal models of your design.
• √ Simulation & specification confirmation
• √ Production, based on completion of design validation & computer simulation, our engineers work closely with project leader to map out production plan, and production will be carried out strictly according to the specification.
• √ Test and quality check, a comprehensive testing and checks will be carried out immediately after completion of production, covering magnetic field test, inductance, resistance, hipot, measurement and thermal testing.
• √ Packing and delivery, we provide custom packing solution to make sure that our products can stand long haul transportation.

Fabmann offers full project management services to your exact expectation, and we handle everything from design to quality assessment.