# A Novel Approach on the Unipolar Axial Type Eddy Current Brake Model Considering the Skin Effect

^{1}

^{2}

^{3}

^{4}

^{5}

^{*}

## Abstract

**:**

## 1. Introduction

## 2. Working Principle

## 3. Governing Equation

^{2}). In this paper, the pole shoe used was rectangular, in which a represents the length (m), and b is the width (m), as shown in Figure 1b. Thus, the total power loss due to eddy current, ${p}_{d}$ (W), is calculated based on the volume of the affected conductor area, volume = S × d (m

^{3}).

^{2}), which is a variable and the value can be adjusted during operation. The eddy current value is proportional to the rotational speed and the magnetic field density. In the same magnetic field density, increasing the rotational speed will produce more eddy currents. While the magnitude of the magnetic field density, B, is the result of the division of the magnetic flux, ɸ (Wb), with a cross-section of the magnetic field area, S (m

^{2}), (B = ɸ/S). The strength of the magnetic flux acting on the surface of the conductor depends on the source of the magnetic field, where the source of the magnetic field can be obtained from a permanent magnet or electromagnet.

#### 3.1. Braking Torque using the Correction Factor

#### 3.2. Skin Effect Consideration

## 4. Methods

#### 4.1. Simulation

#### 4.2. Experimental Setup

## 5. Result and Discussion

#### 5.1. Braking Torque at Low-Speed Calculation Using a Correction Factor

#### 5.2. Braking Torque at Low-Speed Calculation with Skin Effect Consideration

#### 5.3. Braking Torque Performance Comparison

#### 5.4. Experimental Validation

## 6. Conclusion

## Author Contributions

## Funding

## Conflicts of Interest

## References

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**Figure 1.**Unipolar axial type eddy current brake (ECB): (

**a**) 3D model in general structure, (

**b**) eddy current and design variable and (

**c**) air gap in cross section area.

Variable | Unit | Value |
---|---|---|

Current (i) | A | 20 |

Number of turns (N) | − | 360 |

Length of pole shoe (a) | mm | 30 |

Width of pole shoe (b) | mm | 12.5 |

the total length of the winding core (l) | mm | 248 |

Distance from center to pole shoe center (r) | mm | 83.5 |

Air gap (t) | mm | 0.5 |

Disc thickness (d) | mm | 5 |

The radius of disk brake (R) | mm | 120 |

Relative permeability of aluminum (μ_{Al}) | − | 1.000022 |

Relative permeability of iron (μ_{Fe}) | − | 400 |

The conductivity of aluminum (α) | Ωm | 2.06 × 10^{−7} |

Torque Equation | Low Speed | All Speed | ||
---|---|---|---|---|

Average Error (Nm) | Root Mean Square Error (Nm) | Average Error (Nm) | Root Mean Square Error (Nm) | |

Equation (5) (correction factor) | −0.73 | 1.78 | 9.95 | 14.63 |

Proposed equation (skin effect) | −0.83 | 1.16 | 0.61 | 1.79 |

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**MDPI and ACS Style**

Waloyo, H.T.; Ubaidillah, U.; Tjahjana, D.D.D.P.; Nizam, M.; Aziz, M.
A Novel Approach on the Unipolar Axial Type Eddy Current Brake Model Considering the Skin Effect. *Energies* **2020**, *13*, 1561.
https://doi.org/10.3390/en13071561

**AMA Style**

Waloyo HT, Ubaidillah U, Tjahjana DDDP, Nizam M, Aziz M.
A Novel Approach on the Unipolar Axial Type Eddy Current Brake Model Considering the Skin Effect. *Energies*. 2020; 13(7):1561.
https://doi.org/10.3390/en13071561

**Chicago/Turabian Style**

Waloyo, Hery Tri, U Ubaidillah, Dominicus Danardono Dwi Prija Tjahjana, Muhammad Nizam, and Muhammad Aziz.
2020. "A Novel Approach on the Unipolar Axial Type Eddy Current Brake Model Considering the Skin Effect" *Energies* 13, no. 7: 1561.
https://doi.org/10.3390/en13071561