Magnet Knowledge! How Much Do You Know?

1, Remanent Magnetic Induction Intensity The Magnetic Induction Intensity Value Of Permanent Magnet Material When The External Magnetic Field Is Zero After Magnetization To Saturation. This Index Data Is Directly Related To The Magnetic Density Of The Air Gap In The Motor. The Higher The Magnetic Induction Intensity Value Is, The Higher The Air Gap Magnetic Density Of The Motor May Be, And The Main Indicators Of The Motor Such As Torque Constant And Back Potential Coefficient Will Reach The Optimal Value. Only When The Value Relationship Between The Electric Load And The Magnetic Load Of The Motor Is The Most Reasonable, Can The Efficiency Reach The Best.
2, Coercivity Hc, (magnetic Induction Coercivity Hc B) In The Case Of Saturated Magnetization Of Permanent Magnet Materials, When The Remanent Magnetic Induction Br Is Reduced To Zero, The Required Strength Of The Reverse Magnetic Field. This Index Is Related To The Demagnetization Ability Of The Motor, Such As Overload Multiple And Gap Magnetic Density. The Larger The Hc Value Is, The Stronger The Anti-demagnetization Ability Of The Motor, The Larger The Overload Multiple Is, And The Stronger The Adaptive Ability To The Dynamic Working Environment Of Strong Demagnetization Is. At The Same Time, The Air Gap Magnetic Density Of The Motor Will Be Improved.
3. Maximum Magnetic Energy Product Indicates The Maximum Magnetic Field Energy Provided By Bhmax Permanent Magnet Material To The External Magnetic Circuit. This Index Is Directly Related To The Amount Of Permanent Magnet Material In The Motor. The Larger Bhmax Is, The Greater The Magnetic Field Energy That The Permanent Magnet Material Can Provide To The External Magnetic Circuit, That Is, The Less Permanent Magnet Material Is Used In The Motor With The Same Power.
4. Intrinsic Coercivity Hc I Refers To The Magnetic Field Strength Value When The Remanent Magnetization M Drops To Zero. The Hc B Value Corresponding To B=0 On The Demagnetization Curve Only Means That The Permanent Magnet Cannot Provide Energy To The External Magnetic Circuit At This Time, But It Does Not Mean That The Permanent Magnet Does Not Have Energy Itself. However, When M=0, The Corresponding Value Of Hc I Indicates That The Permanent Magnet Has Been Truly Demagnetized And There Is No Magnetic Field Energy Stored. Although Hc I Is Not Directly Related To The Operating Point Of The Motor, It Is The Real Coercivity Of The Permanent Magnet Material, Representing That The Permanent Magnet Material Has Magnetic Field Energy And The Ability To Resist Demagnetic Field. The Intrinsic Coercivity Is Closely Related To The Temperature Stability Of Permanent Magnet Materials. The Higher The Intrinsic Coercivity, The Higher The Operating Temperature Of The Permanent Magnet Material May Be.
5. Temperature Coefficient α Temperature Is One Of The Main Factors Affecting The Magnetic Properties Of Permanent Magnet Materials. When The Temperature Changes By 1℃, The Percentage Of Reversible Magnetic Properties Is Called The Temperature Coefficient Of Magnetic Materials. The Temperature Coefficient Can Be Divided Into Remanent Magnetic Induction Temperature Coefficient And Coercivity Temperature Coefficient. This Index Has A Great Influence On The Performance And Stability Of The Motor. The Higher The Temperature Coefficient, The Greater The Change Of The Index When The Motor Runs From The Cold State To The Hot State, Which Directly Limits The Operating Temperature Range Of The Motor. It Indirectly Affects The Power Volume Ratio Of The Motor.
1. The Actual Magnetic Properties Of Permanent Magnet Materials Are Related To The Specific Manufacturing Process Of The Manufacturer, And There Is Often A Certain Deviation Between The Values And The Data Specified In The Standard. The Same Brand Of Permanent Magnet Material, Different Factories Or Different Batches Of The Same Factory Will Have A Certain Difference In Magnetic Properties. For The Shape And Size Of The Permanent Magnet Actually Used In The Motor, There Will Be Some Differences Between Its Magnetic Properties And The Standard Data.
In Addition, The Capacity Of The Magnetizer And The Magnetization Method Will Affect The Uniformity Of The Magnetization State And Magnetic Properties Of The Permanent Magnet. Therefore, In Order To Improve The Accuracy Of Motor Design Calculation, It Is Necessary To Obtain The Measured Demagnetization Curve Of The Batch Number Of The Actual Size Permanent Magnet At Room Temperature And Working Temperature From The Manufacturer. It Is Better To Directly Measure The Demagnetization Curve By Sampling When Conditions Are Available, Which Is More Reliable. For The Motor With High Consistency Requirement, It Is Necessary To Detect The Permanent Magnet Material Piece By Piece.
The Magnetic Properties Of Permanent Magnet Materials Are Related Not Only To The Alloy Composition And Manufacturing Process, But Also To The Magnetic Field Heat Treatment Process. Magnetic Heat