116 results about "Magnetic leakage" patented technology

The utility model discloses a kind of stator slot wedge, stator module and disc type motor, and stator slot wedge includes base piece and magnetically conductive part.Base piece is made of non-magnetic material, and base piece includes the main body section of being arranged in the slot of stator core and the inner edge section of being protrudingly arranged at the radial inner end of main body section;Magnetic conductive part is made of magnetic material, and magnetic conductive part is at least assembled in main body section and is inserted with the side slot wall of slot;The part of inner edge section away from main body section along radial direction is provided with main insertion part, main insertion part is used to and is inserted with the main matching part of being arranged in inner ring oil seal plate, and insertion is fixed by colloid adhesion, and the surface of insertion at least part is relatively axial and is inclined to extend.The utility model eliminates magnetic leakage hidden danger as far as possible, optimizes magnetic circuit, improves the operation reliability of complete machine and improves the operation efficiency of complete machine.

The application relates to the technical field of function test, and discloses a stress measurement system for spring fatigue state, which comprises an excitation unit, a sensing unit and a signal processing unit. The excitation unit applies an alternating excitation magnetic field to the spring to generate a stress-modulated induced electromotive force signal. The sensing unit collects magnetic characteristic parameters by using a quadrature differential sensing structure. The signal processing unit obtains phase components in a tangential signal and a radial reference signal, calculates a dynamic spiral angle deflection based on a phase difference, determines a dynamic differential compensation coefficient to extract a tangential principal stress component and compensate for a magnetic flux leakage vector deviation. Through a space posture modulation and lift gap fluctuation suppression mechanism, the application realizes dynamic alignment of a sensor measurement main shaft and a spring stress tensor main shaft, effectively eliminates geometric deflection errors caused by large amplitude deformation, and ensures that the system has high signal-to-noise ratio and baseline stability under cyclic load.

This invention provides an intelligent detection and classification method for oil and gas pipeline defects based on pseudo-color images, belonging to the field of pipeline safety inspection. First, multi-dimensional magnetic flux leakage data of the oil and gas pipeline in the axial, circumferential, and radial directions are obtained through a tensile experiment. The detection data is converted into visualized pseudo-color images, and image defect annotation is completed to construct a standardized pipeline defect dataset. In the detection stage, the dataset is input into a pre-trained YOLOv11 model to achieve accurate identification and location of potential pipeline defect areas. In the multi-view fusion stage, the defect bounding box output by the model is used to extract the target area of ​​the original pseudo-color image. Images of the same defect from multiple directions are stitched together to generate a multi-view pseudo-color image of the defect. In the classification stage, the Patch preprocessing module is used to complete image resizing and filling, and then the image is fed into a finely tuned DINOv3 classification model to efficiently complete the intelligent identification and classification of various pipeline defects.

This invention discloses a non-destructive testing method and system for steel wire ropes based on the fusion of sensing and physical features, belonging to the field of non-destructive testing technology for steel wire ropes. The method first saturates the steel wire rope with an axial Gaussian difference excitation probe to improve the signal-to-noise ratio of the defect leakage magnetic field signal; simultaneously, an inertial measurement unit synchronously acquires instantaneous acceleration. A velocity-signal model is established based on the law of electromagnetic induction to dynamically compensate the original voltage signal of the leakage magnetic field. Then, characteristic parameters with clear physical meaning, such as peak voltage, maximum gradient, and full width at half maximum (FWHM), are quantized and extracted from the standardized leakage magnetic field signal, and fused with deep features extracted by a deep learning model. The fused feature vector is input into a fully connected neural network and a classifier to achieve defect type identification and severity assessment. This invention enables high-precision, interpretable intelligent detection and remaining life prediction of steel wire rope defects, significantly improving detection reliability and supporting predictive maintenance.

An automatic variable flux axial liquid-cooled motor, relating to the field of motor technology, aims to solve the problems of complex and costly weak flux control in existing motors. The motor includes an upper cover and a lower housing with water channels. The stator is installed inside the lower housing, with its core tightly fitted to the water channels for efficient heat dissipation. The rotor is located above the stator and is slidably connected to the output shaft via a spline, allowing axial sliding and stable torque transmission. Four evenly distributed flyweights are arranged on the upper side of the rotor. A return spring is mounted above each flyweight, and a push rod is attached below. The other end of the push rod rests against a shoulder at the spline end of the output shaft (the shoulder serves both positioning and support functions). During operation, as the rotor speed increases, the centrifugal force of the flyweights increases, and the unfolding angle widens, pushing the push rod downwards and causing the rotor to slide upwards. This increases the air gap between the stator and rotor, increasing leakage flux, reducing magnetic flux linkage and back electromotive force, thereby widening the speed range and improving efficiency. When the speed decreases, the return spring resets the flyweights, and the air gap recovers. This structure integrates automatic flux adjustment and axial liquid cooling functions, offering a simple structure and high efficiency.

This application belongs to the field of robotics technology, providing a modular pipeline inspection robot and its control method suitable for pressurized water-filled pipe networks. It includes a head-mounted vision acquisition mechanism, a magnetic flux leakage (MF) detection mechanism, and a propulsion mechanism. The head-mounted vision acquisition mechanism acquires images of the inner surface of the pipe and is rotatably and sealingly connected to the MF detection mechanism. The MF detection mechanism includes a folding mechanism and a MF detection sensor. The folding mechanism is configured to be driven to control the MF detection sensor to be in contact with or away from the inner surface of the pipe. The MF detection sensor is used to acquire pipeline defect data. The MF detection mechanism is rotatably and sealingly connected to the tail-mounted main propeller. The control motherboard adjusts the thrust of each vertical propeller in real time through closed-loop control, controlling the robot to travel along the centerline of the pipe. This robot has a compact structure, flexible movement, can adapt to water-filled and certain pressure environments, and integrates multiple detection methods, improving the reliability and applicability of pipeline inspection.

The application discloses a magnetic assembly of a motor, the motor, a suspension system and a vehicle. The magnetic assembly of the motor comprises a shielding member, the shielding member comprises a plurality of split members, the plurality of split members are matched to define a hollow cylindrical shape, and each split member is a magnetic conductive material piece. A first magnetic exciting member is arranged in the interior of the shielding member, and the first magnetic exciting member is adapted to be coupled with a second magnetic exciting member of the motor to cause relative movement of the first magnetic exciting member and the second magnetic exciting member. The magnetic assembly of the motor according to the embodiment of the application utilizes a plurality of split members to form a shielding member, utilizes the shielding member to reduce magnetic leakage, has the advantages of improving the utilization rate of magnetic force, improving the efficiency and power density of the motor and the like.

The application discloses a transformer adaptive closing method and device, equipment and storage medium, and relates to the technical field of transformer control. The method comprises the following steps: obtaining a winding transient voltage signal in a tripping process of a target transformer, performing numerical integration on the winding transient voltage signal, and obtaining an initial residual magnetism value of the target transformer; obtaining a core leakage flux signal of the target transformer, performing complementary calibration on the initial residual magnetism value based on the core leakage flux signal, and obtaining a dynamic residual magnetism value of the target transformer; determining a target closing time based on the dynamic residual magnetism value of the target transformer, the type of the target transformer and the type of a circuit breaker corresponding to the target transformer; and controlling the circuit breaker to close the target transformer at the target closing time. Through the above method, accurate dynamic measurement of residual magnetism is realized, the ideal closing time with the minimum core residual magnetism and post-closing magnetic flux deviation is adaptively determined according to different transformer types and circuit breaker characteristics, and the magnetic field current surge is effectively inhibited.

This application discloses a BIM-based automatic optimization method and system for substation cable laying paths. The method includes: acquiring a building information model; extracting equipment spatial information, equipment operation information, building structural spatial information, and target cable information; constructing the equipment thermal radiation potential energy field and power frequency magnetic leakage potential energy field; determining the cable type and, based on the cable type, determining the magnetic field repulsion response coefficient, thermal radiation repulsion response coefficient, and bending stiffness coefficient; constructing a virtual cable model; constructing an energy coupling function based on the equipment thermal radiation potential energy field, power frequency magnetic leakage potential energy field, magnetic field repulsion response coefficient, thermal radiation repulsion response coefficient, and bending stiffness coefficient; determining the optimal laying path using the energy coupling function; generating a cable spatial constraint potential energy distribution based on the optimal laying path; and determining all optimal laying paths based on the cable spatial constraint potential energy distribution. This application can effectively improve the accuracy of substation cable laying path optimization.

The application discloses a rotor, a permanent magnet synchronous reluctance motor and a vehicle, and relates to the technical field of rotor design. The rotor comprises a rotor core, and the rotor core is uniformly provided with a plurality of magnetic barrier groups in the circumferential direction; each magnetic barrier group comprises a third group of magnetic steel grooves, a second group of magnetic steel grooves and a first group of magnetic steel grooves which are sequentially and spacedly arranged along the radial direction outward. The first group of magnetic steel grooves is composed of two first magnetic steel groove rows which are symmetric about the d-axis and arranged in a V shape; each first magnetic steel groove is internally provided with a rectangular magnetic steel. The second group of magnetic steel grooves is composed of two second magnetic steel groove rows which are symmetric about the d-axis and arranged in a V shape; each second magnetic steel groove is internally provided with a rectangular magnetic steel. The third group of magnetic steel grooves is composed of two third magnetic steel groove rows which are symmetric about the d-axis and arranged in a U shape; the third magnetic steel groove is a V-shaped groove which is formed by the communication of a magnetic steel groove I section and a magnetic steel groove II section; the magnetic steel groove I section and the magnetic steel groove II section are each internally provided with a rectangular magnetic steel. The rotor of the application can increase the magnetic aggregation capacity, optimize the air gap magnetic flux density waveform, reduce the magnetic flux leakage and improve the magnetic saturation phenomenon.

This utility model discloses a core structure for a high-energy ignition coil used in automobiles, including a core structure installed inside the ignition coil housing. The core structure comprises a magnetic sheet, a primary coil, a secondary coil, and a toroidal core. The magnetic sheet is embedded in the primary coil, which is interference-fitted into the secondary coil. The toroidal core simultaneously surrounds both the primary and secondary coils and is tightly fitted to the magnetic sheet. The end of the primary core furthest from the magnetic sheet is tightly fitted against the toroidal core. The closed magnetic circuit structure of the toroidal core concentrates the magnetic field almost entirely within the core, resulting in minimal magnetic leakage, uniform magnetic field distribution, low magnetic reluctance, and high magnetic flux density. This leads to high energy conversion efficiency, minimal energy loss, and the efficient energy conversion capability enables the ignition coil to generate higher secondary voltage and stronger spark energy. It is suitable for lean-burn and high-performance engines, ensuring reliable ignition and better fuel economy.

This utility model relates to a magnetic isolation slot that effectively reduces motor torque ripple, belonging to the field of motor technology. It includes a protective housing, within which a rotating shaft extends from both ends of the housing. A stator core, nested and fixedly connected to the housing, is located between the rotating shaft and the housing. A rotor, inserted and connected to the rotating shaft, is located between the rotating shaft and the stator core. The stator core includes a core shaft, and its inner wall has several equally spaced, annularly distributed winding posts integrated with the core shaft. Magnetic isolation slots penetrating the front sides of each winding post are provided. It features a simple structure and good operational performance. The magnetic saturation effect of the magnetic isolation bridge or slots limits magnetic leakage, thereby improving the uniformity of the magnetic field distribution and reducing torque fluctuations. The magnetic isolation slots adjust armature reaction, improving commutation performance and reducing the risk of sparking.

The application discloses a kind of surface-mounted permanent magnet motor end effect calculation methods, including steps as follows: S1, under given conditions, define the ratio of magnetic density at the end and center length as leakage magnetic coefficient, and propose the expression of leakage magnetic fitting function to calculate leakage magnetic coefficient;S2, extract the permanent magnet thickness H of sample machine, stack length L and air gap length g as the variable of leakage magnetic fitting function;S3, multiply leakage magnetic coefficient Gl and air gap magnetic density, obtain the magnetic density considering end leakage magnetic in three-dimensional situation;The torque considering end effect is obtained by Maxwell tensor method;The weighted factor G is obtained by integrating leakage magnetic coefficient Gl, and the quasi-three-dimensional result is obtained by multiplying the weighted factor G and two-dimensional model result.The present application has short calculation time, and does not need additional three-dimensional finite element model, realizes the end effect calculation of surface-mounted permanent magnet motor.

The application discloses a kind of based on multi-feature fusion and model learning's electromagnetic detection defect qualitative and quantitative method, builds multi-modal electromagnetic detection system, acquires the multi-frequency eddy current of measured component / multi-channel magnetic flux leakage signal and lift-off data, after adaptive denoising, interference suppression and normalization preprocessing, extract four categories 44-dimensional multidimensional features, obtain optimal feature subset by three-level screening strategy;Adopt channel attention and cross attention mechanism to realize multi-feature adaptive fusion, build "shared backbone+double branch" dual-task joint learning model, complete transfer pre-training, fine-tuning and lightweight compression;Finally output defect qualitative and quantitative results, support dual-technology result fusion and risk rating.The application realizes the full-depth coverage detection of special equipment metal components from surface to middle-deep defects, qualitative classification accuracy is greater than or equal to 98%, depth quantitative average relative error is less than or equal to 5%, single-frame inference time is less than or equal to 10ms, which can be directly deployed on handheld devices to realize real-time detection on site.

This invention provides a dual-layer hybrid structure hybrid magnetic flux-modulated motor, relating to the field of motor design and manufacturing technology. It includes a stator and a rotor disposed inside the stator and rotating relative to it. The stator has an armature winding, and an air gap exists between the rotor and stator. Multiple magnetic pole assemblies are evenly distributed circumferentially inside the rotor. Each magnetic pole assembly includes a first permanent magnet layer and a second permanent magnet layer. The first permanent magnet layer includes a first high-coercivity permanent magnet, and the second permanent magnet layer includes a second high-coercivity permanent magnet and a low-coercivity permanent magnet. The first high-coercivity permanent magnet and the low-coercivity permanent magnet in the second permanent magnet layer form a series structure, while the second high-coercivity permanent magnet and the low-coercivity permanent magnet form a parallel magnetic circuit structure. This invention organically combines "controllable leakage flux" and "memory magnetic flux modulation" through a dual-layer hybrid magnetic circuit structure, enabling the motor to simultaneously possess torque output capability under high load conditions and field weakening speed-enhancing capability under high speed conditions.

A metal magnetic flexible composite inductor conductor and a preparation method thereof; the preparation method of the metal magnetic flexible composite inductor conductor comprises the following steps: S1: taking metal and magnetic material; the magnetic induction intensity of the magnetic material is greater than or equal to 1.6 T; S2: continuously attaching the metal to the magnetic material to obtain a conductive and magnetically conductive composite conductor; S3: cutting the conductive and magnetically conductive composite conductor by using a femtosecond laser processing technology to obtain a spiral flexible composite inductor conductor. The flexible composite inductor conductor prepared by the scheme can obtain a larger self-inductance value under the same size, can effectively suppress leakage magnetic flux, reduce leakage magnetic coupling to the outside world and electromagnetic interference, and can realize a more compact spiral inductor layout by reducing the number of turns or reducing the coil geometric size, thereby solving the problem that high inductance density and low power consumption cannot be simultaneously achieved in the traditional inductor conductor.

This invention discloses a segmented motor stator core with low cogging torque, relating to the field of motor technology. It includes single stator core modules, with the segmented motor stator core composed of several groups of these modules assembled into a ring. Through a sawtooth structure, the magnetic field transition interface formed after the splicing of adjacent single stator core modules exhibits a non-linear, smooth, and gradual change, effectively weakening abrupt changes in magnetic reluctance and making the air gap magnetic field distribution closer to a sine wave. This significantly reduces cogging torque, directly improving the vibration and noise levels during motor operation. Furthermore, the precise semi-circular concave-convex positioning structure at the yoke ensures the accuracy and tightness of the splicing between single stator core modules, guaranteeing the continuity of the magnetic circuit, reducing magnetic leakage, and maintaining the high efficiency of the motor. Simultaneously, a dedicated process positioning groove on the outer diameter of the module provides a stable and reliable clamping reference for the winding process, greatly improving winding efficiency and consistency.

The present application relates to a kind of large-capacity energy-saving amorphous alloy transformer, including shell piece, winding assembly and heat dissipation piece, the outside of shell piece is sleeved with heat dissipation piece, the internal cavity of shell piece is provided with winding assembly, the internal cavity of shell piece contains insulating liquid, winding assembly is soaked in insulating liquid. By using 1K101 high permeability amorphous alloy core, the no-load loss is greatly reduced, the leakage magnetic is reduced, and the energy-saving effect is improved. Through the cooperation of rectangular core and coil cross-section structure, the weight of the core is reduced, the material is saved, and the operating noise is reduced.

This utility model discloses a stamping device, relating to the field of relay processing technology. The stamping device, used to mount a relay frame, includes a base, a pressure plate, and a punch. The base has a movable clamping seat for clamping the relay body. The pressure plate is movably mounted on the base and moves along a direction perpendicular to the base. The punch is located on the side of the pressure plate facing the base and can move closer to or further away from the clamping seat. In the technical solution provided by this utility model, the pressure plate drives the punch to descend and stamp the portion of the lower iron frame located above the upper iron frame. This causes the structure to deform upon impact, thereby pressing the hole that mates with the upper iron frame, thus achieving the installation of the upper and lower iron frames. This avoids the problems of surface blackening and gaps between iron frames, which can easily lead to magnetic leakage, that can occur with laser welding.

A handheld traction steel belt magnetic leakage detection device, belonging to the field of elevator steel belt detection, includes an outer frame, an inner frame, a magnetization module, a magnetic field detection module, and a roller positioning module. The inner frame is installed inside the middle of the outer frame and is divided into an upper inner frame and a lower inner frame. The U-shaped arc surface formed by the upper and lower inner frames fits into the inner U-shaped arc surface of the magnetization module. The magnetic field detection module is installed inside the upper and lower inner frames. The middle part between the upper and lower inner frames is a detection channel for the traction steel belt to be tested to pass through. The detection end of the magnetic field detection module is aligned with the detection channel. A roller frame is installed on each side of the outer frame. Roller positioning modules are installed on the upper and lower sides of the roller frames, respectively. The positioning station between the rollers of the two roller positioning modules is for the traction steel belt to be tested to pass through and be positioned. This invention achieves sensitive and reliable detection, while also possessing good portability and field applicability.

This utility model discloses a low-power water-cooled rectifier power supply, including a chassis with a heat sink installed inside. Transformer assemblies and synchronous rectifier modules are mounted on both sides of the heat sink. The transformer assembly includes a magnetic core, which is horizontally mounted above the synchronous rectifier module. Heat sinks are mounted on both the top and bottom of one end of the heat sink, and IGBT modules are mounted on both heat sinks. The heat sink and heat sinks form a gradient thermal bridging structure. This utility model uses an integrated magnetic core, which not only reduces the size but also reduces magnetic leakage by more than 10%. It also employs a copper-aluminum gradient thermal bridging structure, indirectly connecting the IGBT module and the heat sink via heat sinks, changing the heat conduction mode and making it unaffected by water temperature, thus solving the condensation problem. Simultaneously, the copper heat sink acts as a high thermal conductivity zone, making close contact with the IGBT module, while the aluminum heat sink expands the heat dissipation area, resulting in a 60% reduction in thermal resistance.

This application proposes a double-layer magnetic circuit salient-pole permanent magnet rotor and a semi-direct-drive permanent magnet generator including the same structure. The double-layer magnetic circuit salient-pole permanent magnet rotor includes a rotor core; an inner excitation assembly disposed on the outer wall of the rotor core, the inner excitation assembly containing a plurality of spaced radial permanent magnets and a fixing plate disposed between the radial permanent magnets, the magnetic poles of the radial permanent magnets being staggered; and an outer excitation assembly disposed on the outer wall of the inner excitation assembly, the outer excitation assembly containing a plurality of spaced magnetic pole cores, tangential permanent magnets, and a rotor slot wedge disposed at the radially outer end of the outer mounting slot, the magnetic poles of the tangential permanent magnets being staggered, and the tangential permanent magnets and the radial permanent magnets being staggered and aligned. The inner radial magnetic circuit of this rotor reduces the magnetic leakage coefficient, and the outer tangential magnetic circuit increases the magnetic flux per pole, generating a significant reluctance torque and improving the power factor and power density.

The application discloses a kind of probe devices for magnetic flux leakage detection equipment, it is related to nondestructive testing technical field, it includes probe device, two are symmetrically and oppositely arranged in probe device, each probe device includes bearing table, probe frame, probe limiting component and magnetic yoke component are set on bearing table, probe frame is provided with probe main body, probe limiting component is connected with probe frame, magnetic yoke component is C-shaped, its inside forms a C-shaped cavity, at least a part of probe main body is inserted into C-shaped cavity;Probe limiting component can actively adjust the position of probe main body, can also provide push-pull force for probe main body when working, so that probe main body always remains stable, it is favorable to improve the detection effect of probe main body, probe main body telescopic in the C-shaped cavity of magnetic yoke component, increase the response time of magnetization, detection, it is favorable to improve detection efficiency and detection accuracy.

Disclosed in the embodiments of the present invention is a short-circuit fault detection method for transformer windings. The method comprises: acquiring magnetic flux leakage data between transformer windings; on the basis of the magnetic flux leakage data, determining a short-circuit faulty region; constructing a transformer finite-element model; on the basis of the short-circuit faulty region, performing simulation on the transformer finite-element model, so as to acquire a short-circuit database; and collecting in real time the magnetic flux leakage data between the transformer windings, and on the basis of the short-circuit database, determining a short-circuit faulty position of the transformer windings. By means of acquiring magnetic flux leakage data, determining a short-circuit faulty region, constructing a finite element model, performing simulation to acquire a short-circuit database, and positioning a fault in real time, the present invention realizes the accurate detection of short-circuit faults of transformer windings. The method not only improves the accuracy and efficiency of fault detection, but also provides a strong guarantee for the safe operation of transformers.

This invention relates to the field of electronic component technology, and particularly to a low-loss assembled inductor and its preparation method. The inductor includes a first magnet, a second magnet, a third magnet, a first winding, a second winding, a third winding, and adhesive located at the gap between the magnets. The first winding and the second winding are fixed by the first magnet and the second magnet, respectively, forming a circuit. The magnets and windings define first to third magnetic circuit regions, wherein the area of ​​the second magnetic circuit region is not less than the sum of the areas of the first magnetic circuit region and the third magnetic circuit region, and not more than twice the sum of these areas. The magnets are formed of an alloy powder composite material, the surface of which is coated with mesoporous oxide and uses a coarse-fine particle size distribution. The adhesive is a composite adhesive of epoxy resin, polytetrafluoroethylene, and porous magnetic materials. This invention can balance magnetic flux, reduce leakage flux and high-frequency eddy current losses at the assembly gap, improve high-frequency quality factor, and reduce DC resistance.

This application discloses a stator-partitioned DC-biased hybrid excitation motor based on U-shaped permanent magnets, which can be widely used in the field of motor technology. By partitioning the outer and inner stators, this application ensures a reasonable spatial distribution of permanent magnets and armature windings, eliminating spatial conflicts between the armature windings and permanent magnets, and effectively improving the motor's torque density and operating efficiency. Simultaneously, the use of a U-shaped inner stator permanent magnet and a multi-excitation source hybrid excitation structure with DC components allows for flexible adjustment of the motor's air gap magnetic field, thereby effectively improving the motor's torque density and magnetic field regulation capability, and expanding the motor's speed range. Furthermore, the U-shaped stator permanent magnet structure enables magnetization and reduces magnetic leakage, effectively improving the motor's magnetic field regulation capability and torque density.

The present application relates to the technical field of oil online monitoring and electromechanical equipment state monitoring, in particular to a new energy vehicle electric drive assembly oil circuit abrasive particle detection device and method, comprising a clippable permanent magnet differential excitation assembly for establishing an axial background magnetic field in a detection area; an axial interval and detection area limiting assembly for limiting the axial position relationship of the magnet group relative to the center of the detection area; a six-channel radial induction coil array assembly for collecting the radial magnetic flux change caused by the abrasive particles passing through the detection area and outputting the corresponding channel induction voltage signal; a magnetic isolation assembly for suppressing external magnetic interference and reducing the influence of permanent magnet leakage on the non-detection area; a six-channel acquisition circuit and output assembly for signal conditioning and synchronous sampling of the six-channel induction voltage signal and outputting abrasive particle event information; the present application is suitable for long-term online monitoring of new energy vehicle electric drive assembly lubricating oil circuit and other scenes.

This invention discloses a magnetic flux leakage (MF) internal detection system and method for tee branch pipes, belonging to the field of pipeline inspection technology. It addresses at least one of the following problems with existing detection equipment: reliance on unidirectional fluid pressure drive, difficulty in operation within passive tee branch pipes or risers, difficulty in achieving tight adhesion between the magnetized structure and the pipe's inner wall, and difficulty in controlling the operating speed of the detection equipment. The MF internal detection system of this invention includes a MF detection module, a cable reel drive module, a mileage measurement module, and a control module. The MF detection module is fixedly connected to the cable reel drive module. The control module controls the movement of the MF detection module within the pipeline via the cable reel drive module. The mileage measurement module is fixed to one end of the cable reel drive module near the MF detection module and is used to calculate the MF detection module's speed within the pipeline and locate the position of defects within the pipeline. This invention can be used for defect detection on the inner wall of tee branch pipes.