Electromagnetic Hammer Research Articles

Study of operating modes of electromagnetic hammer with adjustable impact energy and blow frequency

The current work was designed to study the operating modes of electromagnetic impact mechanism (electromagnetic hammer) comprising idle and working stroke windings that are enclosed in magnetic conductor, and reciprocating ferromagnetic striker. Investigation was conducted by modelling in MATLAB environment and performing verification tests with different hammers. Simulation model of the hammer was derived using experimentally obtained static characteristic curves of flux linkage and thrust force for each of the windings. Results revealed that at maximum working stroke winding voltage-varying idle stroke winding voltage, the impact energy did not change, but the impact frequency varied between 0-187 bpm. At maximum idle stroke winding voltage and working stroke winding voltage ranging between 0 to maximum value, the impact energy varied between 84-360 J, the impact frequency varied between 96-187 bpm. Maximum losses over the working cycle were associated with electric losses in the hammer windings and can be reduced by reducing winding currents through increasing the striker speed. The mathematical model of the current study allowed quantifying energy parameters of the electromagnetic hammer. The impact machine cycle includes three operating modes, each determines the main energy parameters: efficiency, impact energy, and cycle time.

RESEARCH OF DYNAMICS OF MOVEMENT OF ELECTROMAGNETIC HAMMER BATTLE IN VISCOUS LIQUID

Many Russian oil fields enter the final stage of development. They implement enhanced oil recovery methods (EOR). Promising EOR include wave effect on the formation by a downhole vibration source based on an electromagnetic hammer. The paper presents the results of a numerical study of the dynamics of striker movement in transformer oil. The dependences of striking speed on oil viscosity, configuration and area of a bypass hole are determined.

Knocking and Listening: Learning Mechanical Impulse Response for Understanding Surface Characteristics

Inspired by spiders that can generate and sense vibrations to obtain information regarding a substrate, we propose an intelligent system that can recognize the type of surface being touched by knocking the surface and listening to the vibrations. Hence, we developed a system that is equipped with an electromagnetic hammer for hitting the ground and an accelerometer for measuring the mechanical responses induced by the impact. We investigate the feasibility of sensing 10 different daily surfaces through various machine-learning techniques including recent deep-learning approaches. Although some test surfaces are similar, experimental results show that our system can recognize 10 different surfaces remarkably well (test accuracy of 98.66%). In addition, our results without directly hitting the surface (internal impact) exhibited considerably high test accuracy (97.51%). Finally, we conclude this paper with the limitations and future directions of the study.

Development and bench tests of a programmable logic controller “Simens Logo” based control system of an electromagnetic hammer for destruction of boulders

The development a programmable logic controller (PLС) based control system of electromagnetic hammer for destruction of boulders is described in the article. During bench tests of the control system, the possibility of using a PLC“Simens Logo” for multi-mode control of electromagnetic actuators of hammer is demonstrated.

Network high-performance grinding devices for ferromagnetic materials

The design features of the grinding devices that implement the impact destruction of the ferromagnetic materials particles in a magneto vibrating layer formed in a non-uniform magnetic field are considered. It is shown that when a magnetizable powder is affected by an alternating magnetic field with certain parameters, a magneto vibrating layer is formed, under the conditions of which, a random perturbing factor occurs. It is caused by the dipole particles clusters interactions and provides highefficient finish powder grinding. Methods for producing metal powders, which are distinguished according to the operating principle and to the requirements for the technological properties of the powders obtained, are analyzed. For coarse grinding, jaw, roller and cone crushers and mullers are used; at this, particles of 1-10 mm in size, which are the source material for fine grinding, are obtained. The finish grinding of the material obtained is carried out on the ball rotating, vibrating or planar centrifugal, vortex and hammer mills. The main drawback of these techniques of metal powder grinding is sticking of grinding body residue on the powder particles, which reduces the quality and operational properties of the powder. A relation to calculate the dependence of the fineness number of ferromagnetic materials on the induction gradient of an external variable magnetic field is proposed. The design features of an electromagnetic mill based on a screw drum that, due to the spatial orientation of its walls, ensures an effective movement of powder flows inside it, such as mixing, rotation, oncoming movement, translational motion and simultaneous advancement through the drum are presented. The concept and technological options of grinding powders in an electromagnetic mobile hammer mill are revealed, which enables to obtain a powder of a given particle size distribution with high uniformity. It is established that mills in which a magneto vibrating layer is implemented are more effective than mechanical ones: grinding of ferromagnetic powders in a magneto vibrating layer increases drastically the performance of the grinding process. Changing the parameters of the electromagnetic field, you can set an average particle size and the degree of homogeneity of the powder.

Future development of mechanical rocks destruction methods without blasting

Currently, the mining industry is undergoing certain difficulties related to the mining and geological conditions became more complicated such as: to start mining at a great depth; the need to involve ores with the low valuable components into the processing; the specific gravity increase of ores mining out of low and extremely low bed seams requiring selective extraction of valuable ores. Under the circumstances the efficiency of ores mining by blasting and drilling methods decreases and the other methods and technologies of deposits development are to be worked out. To enlarge rocks destruction efficiency by powerful percussive machines claims increasing the technological and functional capabilities of this like machines, and expanding application range of technologies without blasting. Hydraulic hammers have become widespread as the attachments, however, their operating efficiency slows down at low temperatures, and they are not able to adapt to the rocks hardness change. The article proposes the design of an electromagnetic hammer developed at the Mining Institute after D.A. Kunayev, having no shortcomings as described above one. The descriptions and test results of the electromagnetic hammer are given which confirmed the possibility to manufacture it at the local factories since it is simple to manufacture and, at the same time, this design operates steadily at minus 40 ° С to plus 40 ° С temperatures, and also regulates energy of a single impact in a wide range. The arrangement of electromagnetic hammers manufacture is established to be one of the steps aimed at implementing the development program of non-commodity sectors of the economy.

Estimated impact force for an electromagnetic hammer

This paper presents a force estimation of an electromagnetic hammer based on the principle of the magnetic force generated by the field of a solenoid that displaces its metal core to strike a structure under analysis. This technique known as the Hammer Impact Test is used as a method for vibration analysis. For the correct electronic system design a mathematical model for the hammer is needed to estimate impact force based on the input electrical current the hammer physical parameters.

Development of an electronic control module and research of dynamic and power characteristics of an electromagnetic hammer for destruction of boulders.

The developed electronic control module of an electromagnetic hammer for destruction of boulders is described and studied in the article. The possibility of using an inductive slot sensor for both controlling electromagnets and for measuring dynamic and energy characteristics is demonstrated. During the research of the possibility of controlling the impact energy of an electromagnetic hammer, the advantage of the method of adjusting the height of the lifting of the armature in relation to the method for controlling the magnitude of the electric current of the electromagnets is clarified.

Influence of the machine hammer peening technology on the surface near material structure of stainless steel X5CrNi18-10

Machine hammer peening (MHP) is a mechanical surface treatment process that leads to increased hardness and induces compressive residual stresses in surface-near layers of the peened workpiece. This fact, in combination with the possibility of phase transformation of the crystal lattice of a processed metastable austenitic to martensitic structure by the application of machine hammer peening, contains great potential. For this purpose, the present study deals with the investigation of the effects of plastic deformation in steel material according to increase the hardness as well as to influence the material structure in near-surface regions by the use of an electromagnetic hammer peening device. The deformation-induced processes of an austenitic stainless steel X5CrNi18-10 (1.4301) at room temperature were investigated.

Design and analysis of a new down‐the‐hole electromagnetic hammer driven by tube linear motor

Percussive-rotary drilling is an effective method for the hard rock drilling. As hydraulic and pneumatic hammers have many problems especially in the deep core drilling, a new electromagnetic hammer driven by a tube linear motor is introduced in this study. The study mainly covers the mechanical structure and electromagnetic design of the hammer, respectively. Due to the direct use of electric power, the electromagnetic hammer has the advantage of high efficiency while it must meet the minimal percussive energy requirement under the limitation of drill pipe diameter. In this study, the validity of electromagnetic design is verified through the finite-element analysis software Ansoft/Maxwell 2D and numerical calculation of electromagnetic force. The working temperature in deep down-hole is relatively high, the influence of high temperature in deep hole on the electromagnetic thrust of the linear motor is then analysed. A motion model of linear motor hammer is established to calculate and analyse the impact power and frequency under different conditions. The results show that the performance of linear motor hammer can reach or even exceed the one of same diameter hydraulic hammer, especially in the low-frequency range. The prototype test also confirms the validity of the design.

맥동파 전자해머 구동시스템의 개발

본 연구는 호퍼와 같은 공정에서 필연적으로 발생하는 스케일 또는 막힘 현상을 방지하기 위해 적용할 수 있는 저주파 전자해머 구동 시스템의 개발에 관한 것이다. 전자기계식 hammering 구동 방식은 진동과 충격량을 동시에 발생시키는 방식으로, 본 논문에서는 전자해머의 특성을 고찰하기 위하여 전자해머에 장착된 직/병렬 스프링 상수 해석을 하였고 발생에너지는 E코어에 부착된 스프링 상수가 모두 같을 경우에 계산된 등가 스프링 상수와 E코어와 I코어 사이의 동작 변위의 곱으로 계산할 수 있음을 보였다. 또한 전자해머의 충격량을 최대화하기 위하여 맥동파 구동 알고리즘을 적용하였으며, 이 알고리즘은 논리 AND 연산과 마이크로 콘트롤러(atmega128)의 타이머 인터럽트와 PWM 기능을 사용하여 구현하였다. 전자해머의 구동회로는 IGBT로 구성된 H-브리지 방식으로 설계하였고, 가속도계 측정법으로 개발한 전자 해머 시스템의 성능을 검증하였다. 실험 결과 제안한 시스템이 기계적 에너지를 양호하게 발생시킬 수 있으며, 호퍼와 같은 공정에 적용할 수 있음을 보였다. This paper proposes the development of a low frequency electronic hammer drive system that is used to prevent scaling or clogging in the hopper process. The electro-mechanical hammering driving method involves the generation of vibration and impact energy. The operation principles of the electromagnetic hammer were considered by parallel/series spring coefficient analysis and the amount of kinetic energy generated was calculated from the product of the equivalent spring constant, which is coupled with the E core and the gap of between the E core and I core. In addition, the Pulsation Driving algorithm was applied to the proposed electromagnetic hammer to obtain the maximizing kinetic energy. This algorithm was then implemented by a logical AND operation process and micro-controller (atmega128) built in functions with a timer interrupt and PWM generation function. The driving circuit of the electromagnetic hammer was designed using the H-bridge type IGBT circuit. The experimental test was performed by usefulness of the developed electromagnetic hammer systems with the acceleration measurement method. The experimental result showed that the proposed system has good kinetic energy generation performance and can be applied to the hopper process.

Experimental study of a vertical column of grains submitted to a series of impulses

We report physical phenomena occurring in a vertical Newton's cradle system. A dozen of metallic spheres are placed in a vertical tube. Therefore, the gravity induces a non-uniform pre-compression of the beads and a restoring force. An electromagnetic hammer hits the bottom bead at frequencies tuned between 1 and 14Hz. The motion of the beads are recorded using a high-speed camera. For low frequencies, the pulses travel through the pile and expel a few beads from the surface. Then, after a few bounces of these beads, the system relaxes to the chain of contacting grains. When the frequency is increased, the number of fluidized beads increases. In the fluidized part of the pile, adjacent beads are bouncing in opposition of phase. This phase locking of the top beads is observed even when the bottom beads experience chaotic motions. While the mechanical energy increases monotically with the bead vertical position, heterogeneous patterns in the kinetic energy distribution are found when the system becomes fluidized.

Transient deformation analysis by a carrier method of pulsed electronic speckle-shearing pattern interferometry

The introduction of a pulsed laser into an electronic speckle-shearing pattern interferometer allows high-speed transient deformations to be measured. We report on a computerized system that permits automatic data reduction by introducing carrier fringes through the translation of a diverging lens. The quantitative determination of the phase map that is due to deformation is carried out by the spatial synchronous detection method. Experimental results obtained for a metal plate transiently deformed by an electromagnetic hammer illustrate the advantages of the proposed system.

Experimental investigation of the dynamic characteristics of carbon fiber epoxy composite thin beams

The dynamic characteristics of high strength symmetrically laminated carbon fiber epoxy composite thin beams were experimentally investigated in a vacuum chamber equipped with a fiber optic vibrometer and the electromagnetic hammer. The measured dynamic characteristics were compared to those calculated by the macromechanical theory based on the anisotropic plate theory and the Bernoulli-Euler beam theory. From the comparison, it was found that the macromechanical theory could accurately predict the dynamic characteristics of the carbon fiber epoxy composite thin beams when the undirectional properties of the composite material were known.

The design of switched eddy-current ironless motors

Proposed herein is a new assembly for a large and low speed high power density electric motor. The new design scheme is conceptually relevant to the functional nature of the electromagnetic hammer. This motor is considered to be of the switched repulsion motor class. However, it is distinguished in its ironless core assembly that provides desirable high power density characteristics. Using advanced power electronics and dynamic feedback control schemes, the motor is configured in two spinning shafts: one for the load; and the other for controls. The concept of the new design is tested on a simulator for its functionality and validity of control schemes.

Improved Impulse-Frequency Response Techniques for Measurement of Dynamic Mechanical Properties of Composite Materials

Abstract The dynamic mechanical properties of composite material specimens are rapidly determined by using two new computer-aided impulse techniques. Small beam specimens are excited in either flexural or extensional vibration by an electromagnetic hammer with a force transducer in its tip, while specimen response is measured with an eddy current probe or accelerometer. A desktop computer/Fast Fourier Transform analyzer system is then used for rapid data acquisition and computation of the complex modulus by curve-fitting to the frequency response function.

Maximal efficiency of an electromagnetic drive

The authors derive an analytic expression for the maximum efficiency of an electromagnetic drive for which the inductance varies according to a hyperbolic law and they determine the conditions under which it is achieved.The equations for hammers, stamps, pumps, tampers, vibrator agitators, and other machines with an electromagnetic drive are shown. It is shown that at the initial instant the armature of an electromagnetic hammer with a drive of optimal efficiency should have the initial velocity 2.7 m/sec. As time passes, all the dynamic characteristics vary according to a parabola while the current in the magnetizing winding remains constant.

Mechanical work of magnetic field energyin electromagnetic machines

1. For improving significantly the utilization of the magnetic field energy to improve mechanical work and the energy characteristics of electromagnetic machines, one must reduce the magnetic resistivity in the idle and working gaps. This is attained by expanding the area of magnetic poles and reducing the idle gap to the minimum allowed by the design. 2. The relative performance of magnetic systems in terms of the conversion of the stored energy of the magnetic field into mechanical work can be evaluated by integral and relative power factors. 3. For electromagnetic machines with a shell-type electromagnet (such as hammer or perforator motor), a magnetic system with a ferromagnetic guide should be used with windows in areas situated under the winding (coils) (see Fig. 3). This guide design improves the efficiency of electromagnetic hammer IE4207 from 46 to 55% and increases the machine’s specific power. Better values of specific energy characteristics and efficiencies are obtained with an electromagnetic machine where expanded polar pieces are used as guides (variant 5, Fig. 4). This system has the integral relative power factor which is the highest among the other variants of magnetic systems studied.

An automatic null method recording manometer

A brief account is given of a simple method of maintaining the position of the mercury meniscus of a manometer within less than 1 mm when pressure across the meniscus occur at a rate of up to 1 cm of mercury per minute. The limits of movement of the meniscus are determined by electrical contacts inserted through the manometer wall. The balancing of a pressure change across the meniscus is effected by the movement of a mercury reservoir raised or lowered by the rotation of a bobbin controlled by an electromagnetic ratchet relay. Each movement of the reservoir is recorded by an electromagnetic hammer.