@George The torque output is under the worst case scenario of accelerating up an incline. The RPM is a “best case” to get the speed required. We suggest selecting a motor with at least the torque and RPM provided as the result. You can always choose a gear motor whose RPM is much greater and use a motor controller to decrease the RPM efficiently.
Hi when choosing a motor is taking the torque calculated using the calculator sufficient or do I need to look at the stall torque?
The torque I got from the calculator is 60ozf-in. If I want to buy a motor rated at 159.7oz-in (stall torque) would this be sufficient?
@ju The torque provided as output is the continuous torque needed under the worst conditions, which would be around 1/4 the stall value. 159 / 4 = 39.75 which might be too low.
hey sir I have 12 v DC motor for two wheeled mobile robot but its not pulse modulated can I drive these motors with l298 motor driver even if the motors are not pulse modulated DC motors
@ted DC motors on their own would have no indication of being “PWM compatible”, except they are meant to be driven by PWM in order to change the speed and direction of rotation. The L298 motor controller is meant to control smaller DC motors which consume only around 1A under max load. Therefore be sure you are not trying to use a large / powerful motor with the L298.
thank you very much sir
i have additional question can l298 motor driver able to drive 12v ,100rpm with gear box dc motor
or would you tell dc motors which are compatible with l298 or l293 motor drivers?
cause sir most of the motors which are available on the market are have most of the time have voltage rating ,power rating and rpm but not the current rating
@ted You need to at least be able to estimate the current consumption under load for the motor. The L298 can normally handle a maximum of 1A. The voltage and RPM alone don’t help.
Sir,
How do we tackle Rolling resistance in case of payloads like 700 kg ?
Should we even consider it?
@Ankit, You mean the inertial needed to make the mass turn ? This tool is intended for some DIY project so might be out of range with a 700kg payload.
Hello Sir, I want to use motors to build robotic arms and I am finding difficulty in calculating the torque so that I can choose the appropriate motor. Since the above tool does give motor torque but why isn’t the factor of length taken into account. Torque increases with the same load placed at a higher length. How should I include length of robotic arms in this calculation?
Hi sir, how do you get the value of angular velocity through calculation? Im finding the suitable motor for solar robot cleaner’s wheels and motor to rotate brush. How to determine the exact vakue for voltage and operating time?
@Adam This tool won’t help you find the motor for the brush - just for the drive wheels. You get the RPM from the robot’s velocity and drive wheel radius (refer to the tutorial for more details). The exact value for voltage is really up to you. We suggest something standard like 6V, 7.4V, 11.1V, 12V… multiples of 1.2V and 3.7V. Operating time will relate to the battery’s capacity.
Okay sir. So how do I need to find motor for the brush? And using formula c = It , why I didnt get the value same as using the calculator method?
@Adam The equations used to determine the torque and RPM needed for the brush are completely different than those used to determine the specs of the drive motors. You cannot use these equations for the brush motor. Unfortunately we do not have such equations readily available.
Can you help me by providing maybe the basic of the equation for the brush’s motor; if it doesnt bring a burden to you. Hope you can help me.
Oh Im sorry. I meant the guideline and formula the determine motor spec for the brushes.
@Adam Ah, thank you for clarifying. Unfortunately DC motor design is beyond the scope of this article.
can you tell me how to calculate on load rpm of brushless dc motor theoretically?