How to calculate motor torque needed

how to calculate motor torque needed

Servo Motor Sizing Spreadsheet

May 18, †Ј The motor torque required at constant speed is the sum of the torque needed to drive the load, the preload torque of the screw assembly, and the torque due to friction of the support bearings and seals. T c = torque at constant speed (Nm) T d = torque to drive the load (Nm) T p = torque due to preload (provided by manufacturer) (Nm). Nov 11, †Ј This attribute of the motor is very useful as the motor is used in a motion control system. The overall torque output of the DC motor system is maintained by monitoring current while the motorТs speed output is varied by controlling the voltage into the motor. Need to quickly calculate and convert speed, torque, and power?

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This is a continuation of me trying to understand torque and stepper motors in my other question. I'm trying to understand the torque a motor would be required to generate to lift a calcylate weight, and the formulas involved. Let's say I have a how to write an artist bio sample mass roughly half a pound then the force of gravity pulling it down is:.

If I have a stepper hod with a spindle for my string that pulls up my motor with a radius of 5 cm. I think my torque needed would be:. So now if I want to move that mass I need to find a stepper motor that can output more than 0. The follow-on to my question is that if I want to see how torue I can move it then I need to look at a Torque speed curve, right?

My confusion is this: do I have to ensure that I'm moving slow enough to get the torque I need, or does that curve say if you need this torque you won't be able to go above this speed because the motor won't let you?

You have the right concept, but slipped a decimal point. The gravitational force on your g mass is 4. However, that is the absolute minimum torque just to keep the system in steady state. Calculage leaves nothing for actually accellerating the mass and for overcoming the inevitable friction. To get the real torque required, you have to specify how fast you want to be able to accellerate this mass upwards.

That, in addition to the 4. There will be some friction and you want calculahe margin, so in this example a 0. Note also that torque isn't the only criterion for a motor. Power is another important one. For that you have to decide what's the claculate speed you want to torqeu able to pull the mass upwards at. From above, we know the highest upwards force is 5. After accounting for some losses due to friction and leaving a little margin, the motor should be rated for about 15 W minimum.

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Create a free Team What is Teams? Learn more. Understanding required torque for a motor lifting a weight Ask Question. Asked 5 years, 11 months ago. Active 2 months how to castrate a piglet. Viewed 70k times. Improve this question. Trent 4 4 bronze badges. So many sites show you an algebra formula mootor leaves you more puzzled than when you started. Personally, trying to work out the motor power needed to move a pivot in scissor lift arrangement forward 25cm when there how to get dog urine stains out of concrete 10kg fore and aft of another pivot point!!

Add a comment. Active Oldest Votes. Improve this answer. Olin Lathrop Olin Lathrop 11k 1 1 gold badge 17 17 silver badges 33 33 bronze badges. Your explanation was really good and clear but I have a question: let's say I want to spin the motor very fast so I can pull up the weight fast. Note that the power required to sustain the upward speed still has to be there.

I couldnt believe what I was saying was correct Neded amazing! Of course I think that friction may rise exponentially so maybe at a high speed I will have to provide a huge torque in order to fight the friction, am I correct? However, there are two gotchas with this. First some part of the friction will be proportional to speed viscous friction.

Air drag is even worse, proportional to the square of the speed. Second, the power required is the speed times the torque. You were very very very clear! I finally could understand it.

It may look obvius at last but my misconception abouth phisics made this a little confused, but now you made it very clear! Show 3 more comments. Sign up or log in Sign up clculate Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, calxulate never shown. The Overflow Blog. Podcast How to build and maintain online communities, from gaming toЕ. Level Up: Creative Needev with p5. Featured on Meta. Stack Overflow for Teams is mltor free for up to 50 users, forever.

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4.95 cu in PTO Drive Motor Dynamic BMSY-80-E2-SL-S

The rotor always rotates slightly slower than the statorТs magnetic field and is always trying to Сcatch upТ to it, which is what creates the torque needed to get the motor running. To adjust the speed of a three-phase AC motor, you can adjust the frequency of the AC motorТs power supply using a control. In a ideal system with no friction, the torque to maintain 10 m/s and m/s is the same, but the power required to produce that torque at the higher speed is times more. If you needed 15 W at 10 m/s, then you'll need kW at m/s. $\endgroup$ Ц Olin Lathrop Apr 19 '16 at Dec 19, †Ј To calculate the horsepower of a car, start by finding the engineТs torque value and engine speed in the ownerТs manual. Multiply the torque by the engine speed, and then divide that number by The answer is the horsepower for the carТs engine.

The goal of a motor is to get something to move. The more efficient the motor, the less energy wasted as heat, friction and so on, and the more ultimate cost savings to a business owner in a manufacturing scenario. You might expend a given number of joules crossing a parking lot, but if you sprint and cover the distance in 20 seconds rather than amble and take two minutes, your power output is correspondingly higher in the sprinting example.

Efficiency is simply output useful power divided by input power, with the difference being losses due to imperfections in design and other inevitabilities. Efficiency in this context is a decimal varying from 0 to 1.

Usually, the more powerful the motor, the more efficient it is expected to be. An efficiency of 0. Sometimes you are given the efficiency in a problem and asked to solve for a different variable, such as the input power. In this case you rearrange the equation as needed. Sometimes you are given the parameters of a motor, such as its torque force applied about an axis of rotation and its revolutions per minute rpm.

Kevin Beck holds a bachelor's degree in physics with minors in math and chemistry from the University of Vermont. Formerly with ScienceBlogs. More about Kevin and links to his professional work can be found at www.

The constant factor 0. References U. Copyright Leaf Group Ltd.

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