The process of motion sizing can, in a simplified way, be described as consisting of the steps listed in the table. The sequence of steps is not consecutive, but rather iterative. At any time, you can - or may have to - return to an earlier step. It may occur, for example, that you realize during the device selection phase (step 6) that the mechanic or motion profiles defined in steps 1 and 2 need to be optimized.
|
Step |
Action |
Tools |
|---|---|---|
|
1 |
Design and describe the mechanics of your machine application. |
You can use Motion Sizer to characterize the Mechanic. |
|
2 |
Design and describe the motion of your machine application. |
You can use Motion Sizer to characterize the Motion profile. |
|
3 |
Identify and describe the environmental conditions. |
You can specify the environment in Motion Sizer. Motion Sizer then considers appropriate derating for the selected hardware. |
|
4 |
Decide if you want to define a reserve. For further information on deciding whether to include a reserve, refer to the section How to Improve the Quality of Motion Sizing. |
You can specify a reserve in Motion Sizer which will automatically be observed in the calculations. |
|
5 |
Determine the following characteristics: oThe drive technology oServo motor oStepper motor oBrushless DC electric motor (BLDC) oVariable speed drive (VSD) oThe drive type oCabinet drive oIntegrated drive oDetached drive oSingle drive system oMulti drive system oFurther characteristics oCommunication interface oSafety-related functions oAnd others... Based on these selections, decide on suitable product families to consider in the next step. |
You can use the product catalog available at www.schneider-electric.com to get an overview of available products and their characteristics. |
|
6 |
Select a suitable combination of drive, motor, and gearbox. For further information, refer to the section Detailed Information on Step 6, Selecting A Suitable Combination of Drive, Motor, And Gearbox. |
Motion Sizer can be of help for selecting Lexium products because it compares possible product combinations (Device Selection) with the data you entered for your machine application. The results of the calculations are displayed in the Messages and Results editor (for further information, refer to the chapter Understanding Mechanical Calculation Results). |
|
7 |
Carefully validate the results calculated by Motion Sizer. |
Consult product data sheets and product manuals to validate the results for your machine application. |
|
8 |
Perform system planning concerning: oElectrical requirements oCables oCabinets oAnd others... |
You can consult the product manuals available at www.schneider-electric.com for information on system planning of the individual products. Motion Sizer can help you to define and optimize how braking energy is managed in your machine. It validates whether the solution you are considering will work for the application you specified: In the Power Circuits editor, the software compares the DC bus characteristics of the devices you selected with the corresponding requirements resulting from the application requirements modeled for you (for further information, refer to the chapter Understanding Electrical Calculation Results). |
|
9 |
Create a parts list. |
You can consult the product manuals and the Schneider Electric Product Catalog available at www.schneider-electric.com for the exact references as well as information about required or optional accessories. You can see in the Axis editor, which drive, motor, and gearbox you selected as a basis for the calculations. Consult the corresponding product catalogs and product manuals to determine the exact part numbers and required accessories. Refer to the results shown in the Power Circuits editor of Motion Sizer to help you in selecting suitably sized equipment, such as braking resistor, or capacitor modules, mains fuse, mains contactor, mains filter, mains line reactor (choke) (for further information, refer to the chapter Understanding Electrical Calculation Results). Consult the product manual of the selected drive for the specific requirements and compatibility. |
Detailed Information on Step 6, Selecting A Suitable Combination of Drive, Motor, And Gearbox
In order to select a suitable combination of drive, motor, and gearbox, the following technical criteria are often relevant:
oTorque and speed:
oCharacteristics of the motor and the drive, influenced by factors such as environmental derating, power supply, Pulse Width Modulation (PWM) frequency.
oTorque by speed curve, which displays the maximum torque at the given velocity.
oMaximum peak values and maximum effective values that are supported by the different hardware devices.
oInertia ratio
oRatio of load inertia and motor inertia
oThe good inertia ratio depends on different factors, such as the stiffness of the mechanical coupling, the dynamic of motion, and so on.
If the ratio is <1, then the motor may be oversized.
Typical destination values are within the ranges 1...10 or 1...100.
oThe inertia ratio can be determined at the motor shaft. (In this case, inertia of the load including gearbox is related to the inertia of the motor.)
oIf a gearbox is used in the application, it is often more interesting to determine the inertia ratio at the gearbox output shaft because the mechanical coupling is often less stiff at this point in the machine. (In this case, the inertia of the gearbox is considered to be part of the motor inertia.)
oFurther criteria, such as prices, delivery times, size, spare part optimization, and so on.
How to Improve the Quality of Motion Sizing
The quality of sizing is highly dependent on the quality of the analysis of the machine application that has been made beforehand. The more accurate the selected drive, motor, and gearbox meet the requirements of the application, the better. The use of oversized devices leads to a higher energy consumption, higher prices, bigger sizes, and so on.
In order to improve your results of motion sizing, follow these rules:
oAnalyze your machine application concerning the required mechanics, motion, and environmental conditions.
oDo not inflate values unnecessarily by adding larger values than required by your application, and thereafter adding a buffer in the Reserve to the calculation in Motion Sizer. Enter the value required by your application and if you wish, add a Reserve (buffer) in Motion Sizer.
oIf you have to replace a drive, a motor, or a gearbox in an existing machine application, then perform a full sizing process. If you select a replacement device based on the characteristics of the old device, then the inherent margins will increase with each time. This may lead to more and more oversizing of hardware devices.
