Feed Drive Design for Numerically Controlled Machine Tools
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Stepper Motor Or Servo Motor: Which Should It Be?
Stepper Motor or Servo Motor: Which Should It Be? Engineer the Exceptional ENGINEER THE EXCEPTIONAL ENGINEER THE EXCEPTIONAL Stepper Motor or Servo Motor: Which Should It Be? Engineer the Exceptional ENGINEER THE EXCEPTIONAL Each technology has its niche, and since the selection of either stepper or servo ENGINEER THE EXCEPTIONAL technology affects the likelihood of success, it is important that the machine designer consider the technical advantages and disadvantages of both to select the best motor-drive system for an application. Machine designers should not limit utilization of steppers or servos This article presents an overview of stepper according to a fixed mindset or comfort level, but should learn where and servo capabilities to serve as selection each technology works best for controlling a specific mechanism and criteria between the two technologies. process to be performed. A thorough understanding of these technologies will help you achieve optimum Today’s digital stepper motor drives provide enhanced drive features, mechatronic designs to bring out the full option flexibility and communication protocols using advanced capabilities of your machine. integrated circuits and simplified programming techniques. The same is true of servo motor systems, while higher torque density, improved electronics, advanced algorithms and higher feedback resolution have resulted in higher system bandwidth capabilities as well as lower initial and overall operating costs for many applications. STEPPER MOTOR SYSTEM OVERVIEW Stepper motors have several major advantages over servo systems. They typically cost less, have common NEMA mountings, offer lower-torque options, require less-costly cabling, and their open-loop motion control simplifies machine integration and operation. -
Stepping Motors Fundamentals
AN907 Stepping Motors Fundamentals Author: Reston Condit TYPES OF STEPPING MOTORS Microchip Technology Inc. There are three basic types of stepping motors: Dr. Douglas W. Jones permanent magnet, variable reluctance and hybrid. University of Iowa This application note covers all three types. Permanent magnet motors have a magnetized rotor, while variable reluctance motors have toothed soft-iron rotors. Hybrid INTRODUCTION stepping motors combine aspects of both permanent Stepping motors fill a unique niche in the motor control magnet and variable reluctance technology. world. These motors are commonly used in measure- The stator, or stationary part of the stepping motor ment and control applications. Sample applications holds multiple windings. The arrangement of these include ink jet printers, CNC machines and volumetric windings is the primary factor that distinguishes pumps. Several features common to all stepper motors different types of stepping motors from an electrical make them ideally suited for these types of point of view. From the electrical and control system applications. These features are as follows: perspective, variable reluctance motors are distant 1. Brushless – Stepper motors are brushless. The from the other types. Both permanent magnet and commutator and brushes of conventional hybrid motors may be wound using either unipolar motors are some of the most failure-prone windings, bipolar windings or bifilar windings. Each of components, and they create electrical arcs that these is described in the sections below. are undesirable or dangerous in some environments. Variable Reluctance Motors 2. Load Independent – Stepper motors will turn at Variable Reluctance Motors (also called variable a set speed regardless of load as long as the switched reluctance motors) have three to five load does not exceed the torque rating for the windings connected to a common terminal. -
Stepper Motor
STEPPER MOTOR Stepper motors are used in a wide variety of applications, including computer peripherals like printers, scanners, CD drives, camera lenses, etc. In this first article, in a series of articles on stepper motors, we will introduce the reader to the theory behind the working and control of a stepper motor. Stepper Motor Basics A Stepper Motor just like any other motor, converts electrical energy into mechanical energy. A stepper motor consists of the following parts: Stator The stationary part of the motor. In a stepper motor, the stator is a set of electromagnets. Rotor The non-stationary part of the motor. In a stepper motor, the rotor is a permanent magnet. The arrangement of the electromagnets and the permanent magnets in a simple stepper motor is shown in the following diagram. Stepper Motor Construction Stepper Motor Operation Stepper Motor Operation When each of the electromagnet pairs is energized successively, the permanent magnet is attracted to the electromagnet, and aligns with it. This results in rotation of the permanent magnet. This is illustrated in “Stepper Motor Operation” diagram. The stepper motor gets its name from the fact that the rotor rotates in discrete step increments. The simple stepper motor has a step angle of 90 degrees. More complex stepper motors can have step angles as low as 3.6 degrees. These stepper motors have more no. of poles in the rotor. A complex stepper motor is shown in below diagram. The dark grey areas on the rotor are South poles and light grey areas on the rotor are North poles. -
Stepper Motors
Stepper Motors By Brian Tomiuk, Jack Good, Matthew Edwards, Isaac Snellgrove November 14th, 2018 1 What is a Stepper Motor? ● A motor whose movement is divided into discrete “steps” ○ “Turn 10 steps clockwise” ● Holds its position without additional control ○ No sensor or feedback loop 2 Parts of a Stepper Motor Stator - Stays Static Rotor - Rotates the motor shaft https://phidgets.files.wordpress.com/2014/06/stepper_back_web.jpg 3 Different Types of Torque Holding torque - How much load can the motor hold in place when the coils are energized Detent torque - The torque the motor produces when the windings are not energized, sometimes call residual torque 4 Advantages of Stepper Motors ● Has high holding torque (maintains its position) ● Moves in discrete amounts ● Inexpensive ● Brushless (can last longer than brushed motors) 5 Disadvantages of Stepper Motors ● Uses the same amount of power regardless of load ○ Lower power efficiency ● Torque decreases rapidly as speed increases ● No internal feedback ○ Cannot tell when a step was missed ○ Must step slowly to ensure accuracy ● Low torque to inertia ○ Cannot accelerate loads very rapidly 6 How Stepper Motors Work 7 How a Stepper Motor Works Unpowered Electromagnets Bar with magnetic ends A basic stepper motor consists of a series of electromagnets surrounding a magnetically charged bar 8 How a Stepper Motor Works S Powering a pair of the electromagnets causes the middle bar to align with the electromagnets S 9 How a Stepper Motor Works Changing which electromagnets are powered and unpowered -
Course Description Bachelor of Technology (Electrical Engineering)
COURSE DESCRIPTION BACHELOR OF TECHNOLOGY (ELECTRICAL ENGINEERING) COLLEGE OF TECHNOLOGY AND ENGINEERING MAHARANA PRATAP UNIVERSITY OF AGRICULTURE AND TECHNOLOGY UDAIPUR (RAJASTHAN) SECOND YEAR (SEMESTER-I) BS 211 (All Branches) MATHEMATICS – III Cr. Hrs. 3 (3 + 0) L T P Credit 3 0 0 Hours 3 0 0 COURSE OUTCOME - CO1: Understand the need of numerical method for solving mathematical equations of various engineering problems., CO2: Provide interpolation techniques which are useful in analyzing the data that is in the form of unknown functionCO3: Discuss numerical integration and differentiation and solving problems which cannot be solved by conventional methods.CO4: Discuss the need of Laplace transform to convert systems from time to frequency domains and to understand application and working of Laplace transformations. UNIT-I Interpolation: Finite differences, various difference operators and theirrelationships, factorial notation. Interpolation with equal intervals;Newton’s forward and backward interpolation formulae, Lagrange’sinterpolation formula for unequal intervals. UNIT-II Gauss forward and backward interpolation formulae, Stirling’s andBessel’s central difference interpolation formulae. Numerical Differentiation: Numerical differentiation based on Newton’sforward and backward, Gauss forward and backward interpolation formulae. UNIT-III Numerical Integration: Numerical integration by Trapezoidal, Simpson’s rule. Numerical Solutions of Ordinary Differential Equations: Picard’s method,Taylor’s series method, Euler’s method, modified -
Power Processing, Part 1. Electric Machinery Analysis
DOCONEIT MORE BD 179 391 SE 029 295,. a 'AUTHOR Hamilton, Howard B. :TITLE Power Processing, Part 1.Electic Machinery Analyiis. ) INSTITUTION Pittsburgh Onii., Pa. SPONS AGENCY National Science Foundation, Washingtcn, PUB DATE 70 GRANT NSF-GY-4138 NOTE 4913.; For related documents, see SE 029 296-298 n EDRS PRICE MF01/PC10 PusiPostage. DESCRIPTORS *College Science; Ciirriculum Develoiment; ElectricityrFlectrOmechanical lechnology: Electronics; *Fagineering.Education; Higher Education;,Instructional'Materials; *Science Courses; Science Curiiculum:.*Science Education; *Science Materials; SCientific Concepts ABSTRACT A This publication was developed as aportion of a two-semester sequence commeicing ateither the sixth cr'seventh term of,the undergraduate program inelectrical engineering at the University of Pittsburgh. The materials of thetwo courses, produced by a ional Science Foundation grant, are concernedwith power convrs systems comprising power electronicdevices, electrouthchanical energy converters, and associated,logic Configurations necessary to cause the system to behave in a prescribed fashion. The emphisis in this portionof the two course sequence (Part 1)is on electric machinery analysis. lechnigues app;icable'to electric machines under dynamicconditions are anallzed. This publication consists of sevenchapters which cW-al with: (1) basic principles: (2) elementary concept of torqueand geherated voltage; (3)tile generalized machine;(4i direct current (7) macrimes; (5) cross field machines;(6),synchronous machines; and polyphase -
Piezoelectric Inertia Motors—A Critical Review of History, Concepts, Design, Applications, and Perspectives
Review Piezoelectric Inertia Motors—A Critical Review of History, Concepts, Design, Applications, and Perspectives Matthias Hunstig Grube 14, 33098 Paderborn, Germany; [email protected] Academic Editor: Delbert Tesar Received: 26 November 2016; Accepted: 18 January 2017; Published: 6 February 2017 Abstract: Piezoelectric inertia motors—also known as stick-slip motors or (smooth) impact drives—use the inertia of a body to drive it in small steps by means of an uninterrupted friction contact. In addition to the typical advantages of piezoelectric motors, they are especially suited for miniaturisation due to their simple structure and inherent fine-positioning capability. Originally developed for positioning in microscopy in the 1980s, they have nowadays also found application in mass-produced consumer goods. Recent research results are likely to enable more applications of piezoelectric inertia motors in the future. This contribution gives a critical overview of their historical development, functional principles, and related terminology. The most relevant aspects regarding their design—i.e., friction contact, solid state actuator, and electrical excitation—are discussed, including aspects of control and simulation. The article closes with an outlook on possible future developments and research perspectives. Keywords: inertia motor; stick-slip motor; smooth impact drive; piezeoelectric motor; review 1. Introduction Piezoelectric actuators have long been used in diverse applications, especially because of their short response time and high resolution. The major drawback of these solid state actuators in positioning applications is their small stroke: actuators made of state-of-the-art lead zirconate titanate (PZT) ceramics only reach strains up to 2 . A typical piezoelectric actuator with 10 mm length thus reaches a maximum stroke of only 20 µm.h Bending actuator designs [1] and other mechanisms [2] can increase the stroke at the expense of stiffness and actuation force ([3]; [4] (pp. -
Simple Torque Control Method for Hybrid Stepper Motors Implemented in FPGA
electronics Article Simple Torque Control Method for Hybrid Stepper Motors Implemented in FPGA Stefano Ricci * and Valentino Meacci Information Engineering Department (DINFO), University of Florence, 50139 Florence, Italy; valentino.meacci@unifi.it * Correspondence: stefano.ricci@unifi.it; Tel.: +39-0552758585 Received: 12 September 2018; Accepted: 4 October 2018; Published: 7 October 2018 Abstract: Stepper motors are employed in a wide range of consumer and industrial applications. Their use is simple: a digital device generates pulse-bursts and a direction bit towards a power driver that produces the 2-phase currents feeding the motor windings. Despite its simplicity, this open-loop approach fails if the torque load exceeds the motor capacity, so the motor and driver should be oversized at the expense of efficiency and cost. Field-Oriented closed-loop Control (FOC) solves the problem, and the recent availability of low cost electronics devices like Digital Signal Processors, Field Programmable Gate Arrays (FPGA), or even Microcontrollers with dedicated peripherals, fostered the investigation and implementation of several variants of the FOC method. In this paper, a simple and economic FOC torque control method for hybrid stepper motors is presented. The load angle is corrected accordingly to the actual shaft position through pulse-bursts and direction commands issued towards a commercial stepper driver, which manages the 2-phase winding currents. Thanks to the FPGA implementation, the control loop updates the electrical position every 50 µs only, thus allowing a load angle accuracy of −1/100 rad for a rotor velocity up to 750 rev/min, as shown in the reported experiments. Keywords: stepper motor; torque control; closed-loop control; Field Programmable Gate Array (FPGA) 1. -
Brushless DC Electric Motor
Please read: A personal appeal from Wikipedia author Dr. Sengai Podhuvan We now accept ₹ (INR) Brushless DC electric motor From Wikipedia, the free encyclopedia Jump to: navigation, search A microprocessor-controlled BLDC motor powering a micro remote-controlled airplane. This external rotor motor weighs 5 grams, consumes approximately 11 watts (15 millihorsepower) and produces thrust of more than twice the weight of the plane. Contents [hide] 1 Brushless versus Brushed motor 2 Controller implementations 3 Variations in construction 4 AC and DC power supplies 5 KM rating 6 Kv rating 7 Applications o 7.1 Transport o 7.2 Heating and ventilation o 7.3 Industrial Engineering . 7.3.1 Motion Control Systems . 7.3.2 Positioning and Actuation Systems o 7.4 Stepper motor o 7.5 Model engineering 8 See also 9 References 10 External links Brushless DC motors (BLDC motors, BL motors) also known as electronically commutated motors (ECMs, EC motors) are electric motors powered by direct-current (DC) electricity and having electronic commutation systems, rather than mechanical commutators and brushes. The current-to-torque and frequency-to-speed relationships of BLDC motors are linear. BLDC motors may be described as stepper motors, with fixed permanent magnets and possibly more poles on the rotor than the stator, or reluctance motors. The latter may be without permanent magnets, just poles that are induced on the rotor then pulled into alignment by timed stator windings. However, the term stepper motor tends to be used for motors that are designed specifically to be operated in a mode where they are frequently stopped with the rotor in a defined angular position; this page describes more general BLDC motor principles, though there is overlap. -
London Electricity Companies Had Already Supply Co
printed LONDON AREA POWER SUPPLY A Survey of London’s Electric Lighting and Powerbe Stations By M.A.C. Horne to - not Copyright M.A.C. Horne © 2012 (V3.0) London’s Power Supplies LONDON AREA POWER SUPPLY Background to break up streets and to raise money for electric lighting schemes. Ignoring a small number of experimental schemes that did not Alternatively the Board of Trade could authorise private companies to provide supplies to which the public might subscribe, the first station implement schemes and benefit from wayleave rights. They could that made electricity publicly available was the plant at the Grosvenor either do this by means of 7-year licences, with the support of the Art Gallery in New Bond Street early in 1883. The initial plant was local authority, or by means of a provisional order which required no temporary, provided from a large wooden hut next door, though a local authority consent. In either case the local authority had the right supply was soon made available to local shopkeepers. Demand soon to purchase the company concerned after 21 years (or at 7-year precipitated the building of permanent plant that was complete by intervals thereafter) and to regulate maximum prices. There was no December 1884. The boiler house was on the south side of the power to supply beyond local authority areas or to interconnect intervening passage called Bloomfield Street and was connected with systems. It is importantprinted to note that the act did not prevent the generating plant in the Gallery’s basement by means of an creation of supply companies which could generate and distribute underground passage. -
Electrical Engineering
DEPARTMENT OF ELECTRICAL ENGINEERING Syllabus for M. Tech. Power Electronics & Drives MEE-101 Advance Microprocessors and Applications Max. Marks: 100 (Credit=5) L T P 3 1 2 UNIT I (9 Lecture) Introduction to Microprocessors and Microcontrollers: Review of basics microprocessor,architecture and instruction set of a typical 8-bit microprocessor.Overview of 16 bit and 32 bit microprocessors, arithmetic and I/O coprocessors. Architecture, register details, operation, addressing modes and instruction set of 16 bit 8086 microprocessor, assembly language programming, introduction to multiprocessing, multi-user, multitasking operating system concepts, Pentium-1,2,3 and 4 processors, Motorola 68000 processor.Concepts of micro controller and microcomputer, microcontroller (8051/8751) based design, applications of microcomputer in on line real time control UNIT II (9 Lecture) Input/Output,Memory Interfacing: Parallel and series I/O, Interrupt driven I/O, single and multi-interrupt levels, use of software polling and interrupt controlling for multiplying interrupt levels, programmable interrupt controller, DMA controller, programmable timer/counter, programmable communication and peripheral interface, synchronous and asynchronous data transfer, standard serial interfaces like Rs.232. Types of Memory, RAM and ROM interfacing with timing considerations, DRAM interfacing UNIT III (9 Lecture) Programmable Support Chips: Functional schematic, operating modes, programming and interfacing of 8255, 8251, 8259 and 8253 with microprocessor UNIT IV (9 Lecture) Analog Input & Output: Microprocessor compatible ADC and DAC chips, interfacing of ADC and DAC with microprocessor, user of sample and hold circuit and multiplexer with ADC. Microprocessor Applications: Design methodology, examples of microprocessor applications. Lists of experiments 1. Simple arithmetic operations: Multi precision addition / subtraction / multiplication / division. -
Stepper Motor Basics
Industrial Circuits Application Note Stepper Motor Basics A stepper motor is an electromechanical Disadvantages device which converts electrical pulses into 15° discrete mechanical movements. The shaft 1. Resonances can occur if not A or spindle of a stepper motor rotates in properly controlled. D' discrete step increments when electrical 2. Not easy to operate at extremely B command pulses are applied to it in the high speeds. 1 proper sequence. The motors rotation has 6 several direct relationships to these applied 2 C' C input pulses. The sequence of the applied Open Loop Operation 5 pulses is directly related to the direction of One of the most significant advantages 3 motor shafts rotation. The speed of the of a stepper motor is its ability to be 4 B' motor shafts rotation is directly related to accurately controlled in an open loop D the frequency of the input pulses and the system. Open loop control means no length of rotation is directly related to the feedback information about position is A' number of input pulses applied. needed. This type of control eliminates the need for expensive Figure 1. Cross-section of a variable- sensing and feedback devices such as reluctance (VR) motor. Stepper Motor Advantages optical encoders. Your position is and Disadvantages known simply by keeping track of the input step pulses. Advantages 1. The rotation angle of the motor is Stepper Motor Types proportional to the input pulse. There are three basic stepper motor types. They are : 2. The motor has full torque at stand- N N S N S N still (if the windings are energized) • Variable-reluctance 3.