Calculator
Formula Used
This calculator uses an engineering screening model for eddy current magnetic braking.
F = k × G × B² × A × t × v / ρ
Here, F is brake force. k is the geometry factor. G is the air gap factor. B is magnetic flux density. A is active pole area. t is conductor thickness. v is relative speed. ρ is electrical resistivity.
T = F × r
a = F / m
P = F × v
s = v² / (2a)
ΔT = Q / (mc)
How to Use This Calculator
- Enter the magnetic field strength in tesla.
- Add pole face length and width in meters.
- Enter conductor thickness in millimeters.
- Add relative speed, moving mass, and brake radius.
- Select the conductor material.
- Use custom material fields when needed.
- Adjust the geometry factor for magnet shape and flux coverage.
- Press calculate to view force, torque, heat, and stopping values.
- Use CSV or PDF buttons to save your result.
Example Data Table
| Material | B (T) | Area (m²) | Thickness (mm) | Speed (m/s) | Geometry Factor | Estimated Force |
|---|---|---|---|---|---|---|
| Aluminum | 0.80 | 0.0096 | 6 | 10 | 0.22 | Screening estimate |
| Copper | 0.60 | 0.0060 | 4 | 8 | 0.18 | Screening estimate |
| Brass | 0.90 | 0.0120 | 5 | 12 | 0.25 | Screening estimate |
Magnetic Brake Force Guide
What Magnetic Braking Means
Magnetic braking creates drag without direct contact. A conductor moves through a magnetic field. The changing field creates circulating currents. These are called eddy currents. Their magnetic reaction opposes motion. The result is a smooth braking force.
Why the Force Changes
The force rises when flux density increases. It also rises with active area, conductor thickness, and speed. Low resistivity materials create stronger eddy currents. Copper and aluminum often give strong braking action. Steel behaves differently because magnetic permeability can also affect flux paths.
Using the Geometry Factor
The geometry factor adjusts the simple formula. Real brakes have edge effects, slots, magnet spacing, leakage, and uneven flux. A small factor gives a conservative result. A larger factor is useful when the field covers the conductor well. Test data should be used for final calibration.
Air Gap Effect
The air gap is important. A larger gap weakens the field at the conductor. This calculator applies an exponential correction. It gives a practical estimate for early design work. Use measured flux density at the conductor face when available.
Torque and Stopping Values
Brake torque is found from force and radius. Deceleration is found from force and mass. Stopping time and distance assume constant braking force. In real systems, magnetic braking often drops at low speed. Final mechanical brakes may still be needed.
Heat Considerations
The kinetic energy removed by braking becomes heat. Much of it enters the conductor or rotor. Temperature rise depends on material mass and specific heat. Repeated braking needs thermal checks. Cooling, duty cycle, and safe material limits should be reviewed before production use.
FAQs
What is magnetic brake force?
It is the resisting force created when eddy currents oppose motion through a magnetic field. The force acts against the direction of movement.
Does magnetic braking work at zero speed?
No, eddy current braking needs relative motion. The force becomes very small near zero speed, so a holding brake may be needed.
Which material gives stronger braking?
Materials with low electrical resistivity usually give stronger eddy current braking. Aluminum and copper are common choices.
Why is the geometry factor needed?
Real magnetic fields are not perfectly uniform. The factor adjusts for leakage, edges, magnet shape, and flux coverage.
Can this calculator be used for final design?
Use it for early estimates and comparisons. Final brake designs should use testing, detailed simulation, and safety factors.
What happens when speed increases?
In this simplified model, force increases with speed. At high speeds, saturation, skin effect, and heating may change results.
How does air gap affect braking?
A larger air gap weakens the effective magnetic field. This usually reduces braking force and torque.
Why is temperature rise included?
Magnetic braking converts motion energy into heat. Temperature rise helps check thermal risk during braking events.