Electromagnetic simulation for motors, solenoids and transformers
Electromagnetic simulation predicts the fields, forces, torque and losses in your device, so coils, cores and magnets are sized on predicted performance rather than rules of thumb, and the heat they generate is known before a prototype is wound.
Electromagnetic devices are hard to judge by eye. Flux follows the path of least reluctance, wherever that happens to run. Steel saturates, so doubling the current rarely doubles the force. Eddy currents appear in housings and fasteners nobody thought of as part of the circuit, and leakage flux puts heat where it is not wanted. Equivalent circuits and analytical estimates help early on, but they struggle with real geometry and non-linear materials.
More about electromagnetic simulation
Electromagnetic simulation solves the low-frequency form of Maxwell’s equations over the device and the space around it. Our work covers the range that matters for electromechanical and power equipment: magnetostatic studies for DC coils and permanent magnets, time-harmonic studies for AC excitation, eddy currents and skin effect, and electrostatic studies for insulation and electrode design. Results include flux density, force, torque, inductance and losses, and the losses can be passed to a thermal model to predict the temperatures they cause.
SixGate™ is the design-to-manufacture process of F-CAD®, an engineering company in Glasgow. The engineers who run its electromagnetic studies also design mechanical parts for production, so a study ends with specific changes to the core, coil former or housing.
Typical devices: solenoid valves and linear actuators, electric motors and generators, transformers and inductors, magnetic couplings and brakes, busbars, sensors and high-voltage insulation.
What an electromagnetic study answers
How much force across the stroke?
Force against armature position and current for solenoids and actuators, giving the force-stroke curve the mechanism has to work with.
What torque will the motor produce?
Torque against rotor position and current, including cogging torque and torque ripple, from the geometry of the stator, rotor and magnets.
Where does the steel saturate?
Flux density across the core, showing which sections run into saturation and where material can come out without losing performance.
Where are the losses, and how large?
Copper losses in windings, eddy current losses in solid conductive parts and core losses estimated from the lamination data, located on the geometry.
Is the electric field too high anywhere?
Peak field strength at electrodes, conductors and insulation, showing the sharp edges and small gaps where breakdown or partial discharge is most likely.
What is the inductance?
Inductance and flux linkage across the current range, including the fall in inductance as the core saturates, for drive and control design.
What we analyse
Magnetostatics
DC coils and permanent magnets, with non-linear B-H curves for the steel so that saturation is represented.
Time-harmonic magnetics
Sinusoidal AC excitation at a given frequency, capturing eddy currents and skin and proximity effects in conductors and conductive structures.
Electrostatics
Electric field, potential and capacitance around electrodes, conductors and insulators, for insulation and clearance design.
Forces and torque
Magnetic force on armatures, plungers and magnets, and torque on rotors, at the positions and currents you need.
Inductance and flux linkage
Coil inductance and the coupling between windings, for circuit models, drive tuning and transformer design.
Electromagnetic losses
Joule losses in windings and solid parts, and core losses in laminations, reported component by component.
Permanent magnets
Magnet grade, shape and magnetisation direction compared on flux, force and torque, with the field inside the magnet shown where demagnetisation is a concern.
Coupled electromagnetic-thermal
Losses mapped into a thermal model as heat sources, so winding, core and magnet temperatures are predicted alongside electromagnetic performance.
Before you start
What to send us
- CAD of the device: core, coils, magnets, armature or rotor, and housing
- Winding details: turns, conductor size, and current or voltage
- Excitation: DC, or AC with frequency and amplitude
- Materials: steel grade or B-H curve, magnet grade, conductor material
- Positions of interest, such as armature stroke or rotor angles
- The target: required force, torque, inductance or loss limit
Do you need detailed winding geometry?
Usually not. A coil is normally represented as a region carrying the right number of ampere-turns, rather than as individual wires, unless the current distribution inside the winding is itself the question.
Can you simulate AC devices?
Yes. Time-harmonic studies represent sinusoidal excitation at a fixed frequency. At 50 Hz the skin depth in copper is about 9 mm, so it already affects current distribution in thick busbars and large conductors.
What material data do you need?
For steel, a B-H curve and, for AC work, loss data at the working frequency. For magnets, the grade, or its remanence and coercivity. Supplier datasheets are usually enough to start.
Can the losses be used in a thermal study?
Losses from the electromagnetic model become heat sources in a thermal or conjugate heat transfer model, and that is how winding and magnet temperatures are predicted.
How high can the electric field safely be?
It depends on the insulating medium and the margin you specify. As a reference, dry air at sea level breaks down at roughly 3 kV/mm in a uniform field, and sharp edges concentrate the field locally, which is why electrostatic studies focus on radii and gaps.
Send us your coil, core or magnet
