Free Essays on Stepping Motor

Construction Stepping motors are electromagnetic, rotary, incremental devices which convert digital pulses into mechanical rotation. The amount of rotation is directly proportional to the number of pulses and the speed of rotation is relative to the frequency of those pulses. Stepping motors are simple to drive in an open loop Static or holding torque - displacement characteristic The characteristic of static (holding) torque - displacement is best explained using an electro-magnet and a single pole rotor (fig. 12). In the example the electro-magnet represents the motor stator and is energized with it's north pole facing the rotor Figure 12 Curve illustrating static torque verses rotor position Assuming there are no frictional or static loads on the rotor, fig. 11 illustrates how the restoring torque varies with rotor position as it is deflected from it's stable point. As the rotor moves away from it's stable position, the torque steadily increases until it reaches a maximum. This maximum value is called the holding torque and represents the maximum load that can be applied to the shaft without causing continuous rotation. If, the shaft is deflected beyond this point, the torque will fall until it is again at zero. However, this zero point is unstable and the torque reverses immediately beyond it back to the stable point. A pendulum (fig. 13) can also be used to demonstrate the effects we observe. Figure 13 Pendulum effect of static torque verses rotor position Depending on the number of phases, the cycle in figures 11 and 12 would be equivalent to the following number of full steps: 2 phase 4 steps 3 phase 6 steps 5 phase 10 steps The torque required to deflect the shaft by a given angle can be calculated using the formula: Although this static torque characteristic is not a great deal of use on it's own, it does explain some of the effects we observe. For example, it dictates ... Free Essays on Stepping Motor Free Essays on Stepping Motor Construction Stepping motors are electromagnetic, rotary, incremental devices which convert digital pulses into mechanical rotation. The amount of rotation is directly proportional to the number of pulses and the speed of rotation is relative to the frequency of those pulses. Stepping motors are simple to drive in an open loop Static or holding torque - displacement characteristic The characteristic of static (holding) torque - displacement is best explained using an electro-magnet and a single pole rotor (fig. 12). In the example the electro-magnet represents the motor stator and is energized with it's north pole facing the rotor Figure 12 Curve illustrating static torque verses rotor position Assuming there are no frictional or static loads on the rotor, fig. 11 illustrates how the restoring torque varies with rotor position as it is deflected from it's stable point. As the rotor moves away from it's stable position, the torque steadily increases until it reaches a maximum. This maximum value is called the holding torque and represents the maximum load that can be applied to the shaft without causing continuous rotation. If, the shaft is deflected beyond this point, the torque will fall until it is again at zero. However, this zero point is unstable and the torque reverses immediately beyond it back to the stable point. A pendulum (fig. 13) can also be used to demonstrate the effects we observe. Figure 13 Pendulum effect of static torque verses rotor position Depending on the number of phases, the cycle in figures 11 and 12 would be equivalent to the following number of full steps: 2 phase 4 steps 3 phase 6 steps 5 phase 10 steps The torque required to deflect the shaft by a given angle can be calculated using the formula: Although this static torque characteristic is not a great deal of use on it's own, it does explain some of the effects we observe. For example, it dictates ...

Complete List of FREE ACT Math Practice Questions

Complete List of FREE ACT Math Practice Questions SAT / ACT Prep Online Guides and Tips Whether you're on a budget or just want to see what kinds of ACT Math study materials you can access for free, you've come to the right place. Though the internet is chock-full of ACT resources of dubious quality, we've collected and put together only the highest quality free ACT Math study materialavailable. So let's jump right in! Note: For guides and reviews of the best for-pay ACT study, check out our list of ACT study links, which includes all official practice tests, and our top picks for ACT prep books. Why You Must Use High-Quality ACT Math Materials Because the ACT is a very specific type of standardized test, it's crucial that you study using the right sources. Studying with the wrong materials is about as bad as not studying at all,and there are, unfortunately, a lot of poorly designed ACT prep materials floating around. So don’t be tempted by the many websites and programs, both free and paid, that provide ACT prep materials of poor quality. If you spend your time studying from inferior materials, you will not have a clear sense of how you’ll perform on the ACT.Proper test prep is about assessing your current level and improving upon it, but you won’t be able to do this if you get a false sense of your skill level (either higher or lower) based on low-quality study materials. In short, any practice problems that don't properly reflect the types of questions you’ll see on the ACT aren't worth your time! Knowing this, the absolute best study strategy is to use official ACT materials.The test is designed by ACT, Inc., and their free materials are far and away the best place to start. From here, you can then branch off to programs and resources that utilize (or closely resemble) this official material. Because you should only be studying from websites and programs that are as close to the source (i.e., the official ACT) as possible, there sadly aren't a whole lot of free materials available. That said, we've found a couple of solid free ACT Math resources you can use in your prep. Read on to see what these are! The 4 Best Resources for Free ACT Math Practice Here are four super helpful websites you can use to help you make the most of your ACT Math studies- and you don't have to pay a cent for any of them! #1: ACT, Inc. The creator of the test itself, ACT, Inc., should always be your first go-to website for any and all ACT matters. Luckily, they also have a good deal of free study resources, offeringboth complete ACT practice tests and individual Math practice materials. Free Official Full-Length ACT Practice Tests The five tests linked below are the only free tests available from the past 10+ years.Each ACT test includes an optional Writing section and answer key: ACT Practice Test 2015-16 ACT Practice Test 2014-15 ACT Practice Test 20-12 ACT Practice Test 2008-09 ACT Practice Test 2005-06 You might notice that there are missing years here (2006-07, 2007-08, etc.). This is because the ACT repeats tests for different years, meaningthatthe tests for missing years are actually duplicates of the ones above. Note: If you buy the third edition of theACT Red Book, you'll have access to five more official ACT practice tests, but this is obviously not free (around $30 on Amazon).You can also buy the more recent 2017-18 edition of the ACT Red Book, but this oneonlyincludes three practice tests whose questions often overlap with those in the practice tests above. Free Official ACT Math Practice In addition to complete practice tests, the official ACT website providessample math questions with answer choice feedback. These are a full 60 questions in ascending order of difficulty, just like a real ACT Math section. It's essentially another free complete ACT Math test with which you can study! We recommend solving all your questions on paper and then checking your work at the end, rather than checking your accuracy after each question. This method will give you a better sense of how you’ll do on the ACT (remember, you won’t get immediate feedback while you’re taking the actual test!). No need to worry about bills here- most of your ACT studying can be done for free. #2: PrepScholar ACT Blog At PrepScholar, we've compiled tons offree resources for all your ACT Math needs, including detailed guides on every ACT math topic. Our articles give definitions and explanations for major math concepts, offer examples of how you’ll see each topic on the test, and provide ACT practice questions with detailed answer explanations. Below are some of our most helpful content-related resources for the ACT Math section: Numbers Integers (Basic) Integers (Advanced) Fractions, Ratios, Rational Numbers, and Proportions Statistics (Mean, Median, Mode) Probability Sequences Algebra Single Variable Equations Systems of Equations Operations Functions Coordinate Geometry Lines and Slopes Reflections, Translations, and Rotations Plane and Solid Geometry Lines and Angles Circles Triangles Polygons Solid Geometry Trigonometry Trigonometry Formulas The 31 Critical ACT Math Formulas You MUST Know In addition, we have strategy guides to help you solve numerous ACT Math problems across the board: Plugging in Answers Plugging in Numbers You can also sign up for a free five-day trialforour online ACT prep program. This customizable program assesses your current strengths and weaknesses and adapts to your needs based on your progress. It also gives you practice questions tailored to your areas that need improvement and provides expert answer explanations for all questions. The questions we use in our program are all based on real ACT test questions,and, though the full program is not free, we guarantee you your money back if you don't improve your ACT score by 4 points. #3: Ivy Global ACT Practice Test This company offers afree unofficial ACT practice test. Although the math content overall is solid, some questions are slightly easier than those on the actual ACT. In addition, there are no answer explanations, making it hard to determine how to effectively solve questions you got wrong. Otherwise, this PDF offers helpful practice and is a great option if you've already used up all official resources. I recommend using itmainly to digintoextra math questions (instead of taking it as a full-length test). This will help you develop a clearer picture of what math concepts and question types are especially difficult for you. It should also be noted that unlike other ACT websites, Ivy Global does not require you to make an account in order to access its ACT practice material. #4: Khan Academy A partner of the College Board (the creators of the SAT- not ACT), Khan Academy is a great website to use forACT Math practice and review, as long as you know how to use it effectively. I say that because this free prep website only offers a program for the SAT, so you won't find any official ACT practice questions here. That said, you can still use Khan Academy to drill relevant ACT Math concepts and practice those you've learned. Since the ACT, like the SAT, has a big emphasis on algebra, you can use the SAT's Heart of Algebra and Passport to Advanced Math sections for relevant practice. For geometry (which makes up 35-45% of ACT Math), use the High School Geometry page to choose specific concepts and watch videos on them. Finally, for trigonometry, go with the trigonometry and SAT Additional Topics sections. OK, so you've got your study material. Now how do you best use it? How to Use ACT Math Resources Effectively: 6 Key Tips In addition to knowing what material to actually use (and what to avoid) for your ACT Math prep, it's important to know how to best utilize the resources you find. The following six tips will help you achieve your highest ACT Math score using the free prep materials available. #1: Take a Complete Practice Test in One Sitting Though you're probably mostly concerned about your ACT Math score, you still need to know how you'll fare over the course of the full ACT. Answering one or two ACT questions might not be overly challenging, but the test is a marathon: if you aren't prepared, you'll likely find yourself exhausted by the end of it. And exhaustion can cause anyone to make mistakes! So before you dedicate your focus to ACT Math alone, see how your Math score fits into the larger test-taking picture. Plus, a bonus: by taking a full ACT practice test, you'll also be able to see how your Math score does over the course of the entire Math section (remember, questions get harder and harder over the course of the Math test!). #2: Use Proper Timing As you take your complete practice test and any math-specific sections, be sure to follow the proper timing used on the real ACT. Here's a brief overview of how much time you'll get on each ACT section as well as how much (estimated) time you should spend per question: ACT Section Total Time # of Questions Time per Question English 45 minutes 75 36 seconds Math 60 minutes 60 60 seconds Reading 35 minutes 40 53 seconds Science 35 minutes 40 53 seconds Writing (Optional) 40 minutes 1 40 minutes As you can see, you'll have an average of one minute to answer each Math question,and you'll need to know how well you fit into these parameters before test day. It's not worth much if you can answer every question correctly but can't complete the test in time! Don’t worry if you run out of time while taking your first practice test- this is completely normal and gives you a place from which to begin and improve. If the trend continues, however, consider checking out our guide on how to stop running out of time on ACT Math. #3: Review Your Mistakes Taking a practice test is merely the first step. Once you're done with this, focus on identifying any patterns in your correct and incorrect answers so that you can see what and how you need to improve. For example, do you tend to get the last few questions wrong on Math? Dofunction questions always throw you for a loop? Whatever your case, dig deep to examine your errors, andtailor your study plan to drill your most challenging areas. #4: Target Your Areas of Weakness Your goal is to answer as many questions as accurately as possible, so dedicate the majority of your time to improving your areas of weakness. For example, if you're struggling to understand a certain concept, such as systems of equations or coordinate geometry, take time to review it and then use practice questions and tests to ensure you're getting it down. In addition, make an effort to prioritize the first 40 questions or so on ACT Math.Though each question is worth the same number of points, they get more and more difficult as you go through the test. Therefore, it's more efficient in terms of your time and energy to solve two questions in the 20-range than it is to spend twice as much time solving question 60. #5: Pace Your Studying Don’t cram all your studying into one day before the test. With a busy schedule, cramming might seem like your only option, but real improvement happens over time. And yet don't despair, either! No matter how much time you have left before the test, you can make a balanced study program. Start by looking at the time you have before test day. We generally recommend giving yourself at leastthree to six months to study for the ACT; this should be enough time for you to identify your weaknesses, take several practice tests, and review key content. Next, assign yourself at least three full practice tests in addition to your normal studying time, spaced out over the course of your time until the test. This probably won’t be possible if you only have a week or two before the ACT, but it’s still important to fit in at least one practice test or twowherever you can. If you're on an accelerated or last-minute schedule, check out our guides to studying for the ACT in a month andimproving your ACT score in 10 days. #6: No Improvement? Consider Using a Tutor or Prep Program Some students want to do all their studying alone, but for others this method is impractical. If the material doesn't make sense to you and you need extra guidance (or something to get you to make time to study), a tutor or prep program (or both!) can give you the final push you need to do well on the ACT and maximize your score.At PrepScholar, we offer both expert tutoring and a fully customizable online ACT prep program. As you weigh your options, remember to consider how much you should pay for an ACT tutor and when your ACT test date isso you can come up with a surefire plan that works well for you! There are many different study paths, and you'll find the right one for your needs!(maramao/DeviantArt) What’s Next? Want to best make use of your ACT study materials? Now that you've gathered some ACT Math resources, check out how to get the most realistic ACT experience in your practice. Bitten by the procrastination bug? Time running out until test day? Check out how to beat the urge to procrastinate and learn how to balance your time for your ACT prep. Looking to get a perfect ACT score? Take a look at our guides to how many questions you can get wrong and still get a perfect scoreandhow to get a full 36 on ACT Math(written by a perfect scorer!). Want to improve your ACT score by 4 points? Check out our best-in-class online ACT prep program. We guarantee your money back if you don't improve your ACT score by 4 points or more. Our program is entirely online, and it customizes what you study to your strengths and weaknesses. If you liked this Math lesson, you'll love our program.Along with more detailed lessons, you'll get thousands ofpractice problems organized by individual skills so you learn most effectively. We'll also give you a step-by-step program to follow so you'll never be confused about what to study next. Check out our 5-day free trial: