Motor Selection 2

[isb07]

Greetings

Is there any formula to Calculate size of Electric Motor (HP RPM)????

Application:- To drive a structure which runs on steel wheel and steel track... there are total 6 wheels in that frame.

Flow of power will be
Motor>gear Box> Chain Drive >Gear > Wheel

Regards
Ind

 

[itsmoked]

Torque x RPM = HP

Is this for a class?

Keith Cress
kcress -

http://www.flaminsystems.com

 

[isb07]

No sir

actually we manufacture such machine.

Can you give better detail for this as we need to select a motor to drive this structure(which is carrying some weight)
we use magnesium bush for wheel

 

[LionelHutz]

Calculate the force required to accelerate this cart. Maximum weight and quickest acceleration would be the numbers to use for this. It's a simple formula - F=ma

The above force will translate through the pulleys and gearbox to a torque and rpm.

Use the torque and rpm to pick the motor.

Don't forget to account for the losses.

The steps are simple but knowing what numbers to use can be tricky.

 

[isb07]

thanx for ur help

So F=ma
and Torque = F X r
R will be radius of wheel or what???

and HP = torque X rpm

but what about friction???

 

[jraef]

Just be aware, itsmoked's Tq/HP formula was truncated, likey just for the sake of discussion.

It's really
T = 5252 x HP
    rpm

Then use your math skills to convert when you know parts of it from Lionel's information.

(naughty naughty Keith, you know you shouldn't toy with the Mechos like that). ;-)


"Dear future generations: Please accept our apologies. We were rolling drunk on petroleum."
— Kilgore Trout (via Kurt Vonnegut)
For the best use of Eng-Tips, please click here -> faq731-376

 

[LionelHutz]

You will need a certain force just to overcome the friction. There will be a force required to overcome the friction both when stopped and when accelerating. Add it to the calculated F=ma force.

Dont' forget to account for the speed changes and efficiency of the different drivetrain parts (gearboxes and belt or chain drives).

 

[isb07]

thanks everyone

one last thing radius used in torque formula will be radius of wheel???

 

[LionelHutz]

Yes, the radius at the wheel would give the torque at the axle.