What is the rewind scenario if a motor fails Increasing Motor Efficency. Unlike an initial motor purchase where your decision is limited to procuring a standard versus a premium efficiency motor, a motor failure or burnout produces three alternatives. Your options are to rewind the failed motor, purchase a new standard efficiency motor, or purchase an energy efficient replacement motor. What is the rewind scenario if a motor fails For this scenario, motor installation labor costs are again not included as the existing motor must be removed and reinstalled anyway. MRD4-RewindDataWindow.png' alt='3 Phase Motor Rewinding Software Testing' title='3 Phase Motor Rewinding Software Testing' />Threephase motors have fewer components that may malfunction than other motor types. My Maps Google Maps Ipad 2 there. Assuming that the failed motor can be rewound, the baseline or lowest initial cost approach is to rewind the motor to its original specifications. As some older U Frame motors were built with oversized slots, it is sometimes possible to perform a high efficiency rewind and slightly increase the efficiency of the motor by adding more copper to reduce I2. R losses. 5. 0 HP Emergency Motor Rewind Seized motor under repair. If the original unit was wound with aluminum wire, it should be replaced with copper. A motor should be rewound with the same or larger winding wire size and configuration. If a repair shop does not have the correct wire size in stock and uses a smaller diameter wire, stator I2. R losses will increase. While a decrease in the number of turns in a stator winding reduces the winding resistance, it also shifts the point at which the motors peak efficiency occurs toward higher loads and increases the motors mag netic field, starting current, locked rotor, and maximum torque. A change from 1. In a typical rewind, the stator is heated to a temperature high enough to bum out its winding insulation. Department of Civil Engineering was started in the year 2005. The department of Civil Engineering has highly qualified, committed and research oriented faculty. The windings are then removed and replaced. In the past, many rewind shops emphasized speed High temperatures were used to shorten repair times and get the motor back in service quickly. There are several methods to operating a threephase motor using singlephase power to make what would be an otherwise expensive and arduous process a little easier. The following list of contracts is being made available to help ensure that the public has access to government information and policymaking information. The list. Hand held torches were sometimes used to soften varnish for easier coil removal. The resulting higher temperatures increase losses by changing the electrical characteristics of the motors core. For both standard and high efficiency motors, the rewind shop should follow the motor manufacturers rec ommended burnout temperature specifications. When stripping out the old windings, it is essential to keep the stator core below 7. F. If the stator core gets too hot, the insulation between the stator laminations will break down, increasing eddy current losses and lowering the motors operating efficiency. After being damaged, the lamination insulation cannot be repaired nor the efficiency loss restored without under going a major repair such as restacking the iron. The motor also becomes less reliable. Insulation removal techniques vary between rewind shops and should be investigated prior to deciding where to have the motor rewound. Always choose a shop with a controlled temperature winding burnout oven to minimize core loss. Some shops have core loss testers and can screen motors determine if they are repairable prior to stripping. The repair shop should also determine and eliminate the cause for a motors failure. Aside from proper strip ping procedures, the motor owner should ensure that the rewind shop does the following Uses proper methods of cleaning. Installs Class F or better insulation. Uses phase insulation between all phase junctions. Uses tie and blocking methods to ensure mechanical stability. Brazes rather than crimps connections. Uses proper lead wire and connection lugs. Applies a proper varnish treatment. As motor design characteristics such as slot geometry and configuration, failure modes, rewind practices, and materials specifications and treatments vary, it is impossible to identify a typical rewind cost for a motor with a given horsepower, speed, and enclosure. Motor efficiency losses after rewinds also vary considerably. While dynamometer tests conducted by the Electrical Apparatus Service Association indicate that new motors, when properly stripped and rewound, can be restored to their original efficiency, field tests on motors from a variety of manufacturing plants indicate that losses are typically higher in motors that have been rewound perhaps because of thermal shock suffered during the motor failure. An analysis of core loss tests taken over a 1 year period in General Electric repair facilities indicates that average core losses are 3. General Electric also conducted a test of 2. The test indicates that total losses increased by 1. An 1. 8 percent increase in losses corresponds to an approximate 1. Rewound motors can exhibit severe efficiency losses, especially if they were rewound more than 1. Rewind losses of 5 percent or more are possible. When should a energy efficient motor be purchased in lieu of rewinding a failed standard efficiency motor This decision is quite complicated as it depends on such variables as the rewind cost, expected rewind loss, energy efficient motor purchase price, motor horse power and efficiency, load factor, annual operating hours, electricity price, and simple payback criteria. At least some of the time, rewinding will be the best decision. The prospects for a good rewind are greatly im proved if you keep good records on your motors and provide them to the repair shop. Repair shops often cant get complete specifications from manufacturers. They must reverse engineer motors, counting winding turns, noting slot patterns, measuring wire size, etc. Sometimes a motor has failed repeatedly in the past because of a previous non standard rewind. The same error can be repeated unless the shop knows the motor is a repeat offender and di agnoses the problem. Similarly, a motor is sometimes subjected to unusual service requirements, e. Most shops know how to modify original specifications to adjust to such conditions. Rules Of Thumb. Here are several rewind rules of thumb Always use a qualified rewind shop. A quality rewind can maintain original motor efficiency. However, if a motor core has been damaged or the rewind shop is careless, significant losses can occur. Motors less than 1. It is usually best to replace them. If the rewind cost exceeds 6. In creased reliability and efficiency should quickly recover the price premium. If your energy costs average 0. Wh or more, and a motor is operated for at least 4,0. The higher purchase price will usually be repaid through energy savings within 2 years. Here is a chart to help decide when to select an energy efficient motor Choose a new energy efficient motor if Your energy costs are Annual hours of use equals or exceeds 0. Wh. 6,0. 000. 0. Wh. Wh. 3,0. 000. 0. Wh. Table 1 indicates how breakeven rewind costs vary with respect to motor operating hours and simple payback criteria. The breakeven cost is expressed as a percentage of a replacement energy efficient motor price. A new energy efficient motor should be purchased if the rewind cost exceeds the stated breakeven point. Table 1 may be used for NEMA Design B motors in the 5 to 1. Assumptions used in the preparation of this table include an expected 2 percent loss in an average standard motor efficiency due to rewinding, replacement with an average energy efficient motor operated at a 7. Table 1  Breakeven Rewind Cost as a Percentage of an Energy Efficient Motor Price. Simple Payback Criteria YearsAnnual Operating Hours. You can easily complete a cost effectiveness analysis for a rewinding. If you can be assured that the past and prospective rewinds comply with all the foregoing recommended practices, the original efficiency could be maintained. Otherwise, two points should be subtracted from your standard motor efficiency to reflect expected rewind losses. Annual energy and cost savings are determined by inputting the appropriate energy efficient motor performance, operating hours, electricity price, and load factor into Equations below. Moto. Calc. Version 8. This document is Copyright 1. Capable. Computing, Inc. All rights reserved. Unauthorized duplication or publication is. This document may be freely downloaded and printed for. Getting Started. Introduction. Getting Started with Moto. Calc. Whats New. Whats New in Moto. Calc 8 The Moto. Wizard. Using the Moto. Wizard. Making a Performance Prediction. The Moto. Calc Workbench. Specifying Motor Information. Specifying Battery Information. Specifying a Drive System. Specifying a Speed Control. Specifying Airframe Information. Specifying Restrictions. Options. Examining the Results. Generating the Predictions. Sorting the Results. Saving or Printing the Results. Making a Side by side Comparison. Getting an Opinion. Graphing the Results. Displaying Graphs. Graph Controls. Saving or Printing the Graph. Projects. What is a Project Saving a Project. Retrieving a Project. Starting a New Project. Sharing a Project. The Wiring Wizard. How Do I Wire My Plane Wiring Options. Saving or Printing the Diagram. Using the Database Browsers. What is a Database Browser Finding an Item. Selecting an Item. Finding a Similar Item. Deleting an Unwanted Item. Printing a Database Table. Exporting a Database Table. Importing into a Database Table. Updating a Database Table. Obtaining Database Updates. The Update Menu. Updating one Database Table. Updating the Entire Database. Getting User Contributed Data. Contributing Your Data. Tips and Tricks. Finding the Maximum Efficiency Point of a Motor. Gearing and Propping for Maximum Efficiency. Gearing for Maximum Thrust. Choosing an Alternate Motor. Making Use of the Color Coding. Frequently Asked Questions. Caveats. Moto. Calc is a Simulator. All Propellers are not Created Equal. Motor Characteristics can Vary. Static Thrust can be Misleading. Consider the Pitch Speed. Catalog Data can be Sloppy. All Ducted Fans are not Created Equal. Motor Temperature Estimates are Only a Guide. Registration Information. Free 3. 0 day Evaluation. Why Register How to Register. Registering the CD Version. Registering the Evaluation Version. If You Cant Print the Registration Form. If You Dont Want to Register. If You Lose Your Registration. Using Moto. Calc on More than One Computer. More Information. Suggested Reading. Glossary. Electric Flight Terminology. Introduction. Moto. Calc is a program for predicting the performance. You can specify a range for the number of cells, gear. Moto. Calc will. produce a table of predictions for each combination. Moto. Calc will predict weight, current, voltage at. RPM, power loading, electrical efficiency, motor. RPM, propeller or fan RPM, static thrust, pitch speed, and run. By producing a table of predictions, Moto. Calc lets you determine. Moto. Calc can also do an in flight analysis for a. RPM, thrust. pitch speed, propeller and overall efficiency, and run time at. It will also predict stall speed, hands off. Moto. Calcs graphing facility can plot any two parameters. If you have particular requirements, such as a minimum. Moto. Calcs filter facility to filter out. To reduce the amount of information you have to deal with, Moto. Calc. comes with a database of motors, cell types, gearboxes and. For example, the database. Actro, Astro, Aveox, AXI, Graupner, Hacker, Jeti, Kontronik, Kyosho, Max. Cim, Plettenberg, Scorpion, and Turnigy lines, and. If the motor you are using is not included in the. Moto. Calc will help you figure out its parameters from. And if you dont know the aerodynamic characteristics of. Moto. Calcs lift and drag coefficient estimator will. If you are a newcomer to electric flight, Moto. Calcs. Moto. Wizard will ask you a few simple questions about your model. You can then use the. Moto. Calc to investigate one or more of the suggestions. Moto. Calcs Mot. Opinion feature to get a. English analysis telling you how the power system, and your. If you are a bit more experienced, and know some. Moto. Wizard this. Printing This Manual. If you prefer a printed version of this manual, we. Adobe PDF version, which can be found on. Moto. Calc CD as of version 8. Moto. Calc. pdf. A copy can also be found on the Moto. Calc web site at. The manual is about 1. If you dont wish to print it on. They may. ask for proof that you have the right to print it, in which case. PDF file You are hereby. PDF version of. this document for personal use. There are many different ways to use Moto. Calc. This. brief tutorial assumes that you have a model that you are intending. For a more in depth tutorial, please visit. The following is an overview of the steps that will. Moto. Calc to help choose a power. Ask the Moto. Wizard to suggest several. Select one of the Moto. Wizards suggestions, and copy it. Moto. Calc Workbench. Save this as a. Click the Compute Report. Click the Opinion. Mot. Opinion report to help you interpret the. Based on the results above, either go. These five steps are described in more detail below. Step 1. Ask the Moto. Wizard. The Moto. Wizard is described in great detail in its. Instead, well give a brief overview. The Moto. Wizard consists of a number of pages on which. The pieces of information you need to supply are. Ni. Cd, Ni. MH, Li. Po, Li. NP. Based on these specification, the Moto. Wizard will. consider hundreds or thousands of possible electric power systems. Moto. Wizard. and go straight to the Moto. Calc Workbench. Examine the suggestions made by the Moto. Wizard. If. you are unhappy with them for example, suggestions involving. Moto. Wizards option pages. At this point, you can also print the Moto. Wizards. suggestions by clicking the Print. HTML, or comma separated values CSV file by clicking. Save., or copy one or more of the suggestions to the. Windows clipboard to paste into an e mail, for example by clicking. Copy One Result. or Copy All Results. Step 2. Select and Copy to the Moto. Calc Workbench. When you are happy with the Moto. Wizards suggestions. Accept. button. This will fill in the Moto. Calc Workbench window. At this point, you can modify any of the parameters. For example, if the Moto. Wizard is suggesting a. You may also want to specify ranges. Moto. Wizard suggested. Select Save As. from the Project. OK. Step 3. Generate an In flight Analysis. Click the Compute Report. In flight. button. A summary of the project motor, battery, speed control. The last line. of the summary, labeled Stats, summarizes the predicted. Below this you will see a table of predictions at. Using color coding. Step 4. Get Moto. Calcs Opinion. Click the Opinion. Mot. Opinion page. English description of how your plane. Step 5. Revise, Refine, or Fly. Based on the information in the in flight analysis. Mot. Opinion report, you may wish to revise. One way to do this is to return to. Moto. Wizard select Moto. Wizard. from the Project. Moto. Calc Workbench window and either select another. Moto. Wizards suggestions step 1. Moto. Wizard generate. Alternatively, you might just slightly revise the. Moto. Calc Workbench. Or, if you had specified any ranges in step 2, you can select. After a few iterations, you should have narrowed. At this point, its time to install some. Because of variations between simulation. For a much more detailed tutorial, please visit. If you purchased Moto. Calc on a CD, a copy of this in depth tutorial. Tutorial. pdf. Moto. Calc 8 continues the tradition of being the most. Here is a brief summary of. A More Versatile Moto. Wizard. The Moto. Wizard, introduced in Moto. Calc 6, made it easy to choose. In Moto. Calc. 7, the Moto. Wizard became both smarter and faster, looking at more. Now in Moto. Calc 8, it has become more versatile. For example, you might want to use that trusty. Ni. MH battery and Astro Cobalt 0. G motor you have on hand. Now you can tell the Moto. Wizard this, and it will try to find. Or perhaps you have just put the finishing touches. Tell the Moto. Wizard the desired diameter. The list of cell types used by the Moto. Wizard has. also been updated to reflect the changing times. There are more. Lithium Polymer cells, and newer Ni. MH cells. You also have the.