Calculating Motor Power for a New Machine

You will need to determine how much 'work' (force x distance) is being done, and then determine how fast you want to do the work. Power can be calculated from work/time.

Your question is very vauge so the answer must be as well. There are always many variables that effect the sizing of motors, such as acceleration and deceleration times, and motor speed ranges.

thanks for your complete answer

I'm a university student and try to design and build an electrical car . I should find the power that it need for start , climb ramp & receive too the max speed & acceleration.

is in this field any way?

thanks again

If you are a university student trying to design an electric car, and can't do the high school physics to determine the power required , then I suggest that either:

A: You need to let the car wait until you take (or re-take) introductory physics (dynamics). or

B: You have chosen the wrong project!

new Engineer.

We design a boat , how can we calculate the size of the propeller.

Can you see the problem?

First, describe in detail what the machine is suppose to do.

Second, ask if someone has experience in designing such a machine.

Third, The question of the size ( power) of the motor will resolve by itself.

I hope this will clarify how an Engineer should think.

thanks for your answer

I'm a university student and try to design and build an electrical car . I should find the power that it need for start , climb ramp & receive too the max speed & acceleration.

is in this field any way?

the car is small , 300kg ,.......

thanks again

Surely some of your college courses covered that? Otherwise why would you call yourself a new engineer?

thanks for your time

I'm new because try sth new ... designing , building even invent.

again thanks & I try too study more & more be glade too help me

Dear,

Please put some thought in framing your question - It is very vague.

Can you tell us what machine you are designing? I have designed plenty of machines for special applications. First of all you'll have to freeze the specs of the machine, then look for the alternatives available for operating it. More or less the specs of the machine will drive the inputs required for achieving those specs.

Do not ask a question just for the sake of asking. People on this forum are a busy lot and their time is precious and please correct spelling of Engineer.

yesterday I couldn't spell "engineer" and today I is one!

maybe tomorrow you can spell car or E-car.

thanks for your answer

I'm a university student and try to design and build an electrical car . I should find the power that it need for start , climb ramp & receive too the max speed & acceleration a few sec.

is in this field any way?

the car is small , 300kg ,.......

thanks again for your complete advise

Hmm....... Designing an e-car? good. This is in fashion nowadays.

Well you could freeze one entity - the self weight of the car - 300 Kgs.

Add to this:

1. Pay load (for 2 persons with minimum luggage) - say 200Kg?

2. What max speed to achieve in how many seconds?

3. what is the inclination of ramp?

4. what about the power transmission to wheels, I mean, reduction ratio, wheel dia?

Look the things are becoming clearer. Ask yourself more questions and try also to find solution yourself - it is all there in text books. Go ahead and find solution to your initiative.

Best of luck.