Help with electric motor power calculations

[elecar]

That is great, I would love to have seen the output on the motor behind the fly wheel in the 2nd video.

[elecar]

I should of added that a spring balance may be the best way to measure the pull.

[mikestocks2006]

Hi everyone,

I need some electric motor power information that I can't find or don't know how to calculate.

What I would like to know is how many grams of pull force would an 80% efficient electric motor have per Watt in stalled position.

Thanks for your time

Luc

Hi gotoluc,
It appears that you are looking for a basic dynamometer "dyno" to see the output power (mechanical) vs input power electrical, for an electric motor with a rotating shaft for mechanical output.
A prony brake setup might be the easiest/cheapest way to do it. You'll need a couple of force gauges (digital scales), 3-6 $ a piece, a pulley, adopted to fit the motor's shaft, a piece of string, flex cable wire etc. and a way to measure rpm or Hz (rotating frequency of the motor.
Keep the tension lines parallel

The setup/calculations example here
https://www.physics.purdue.edu/demos/display_page.php?item=1K-03

A single force/torque measurement can be used on another setup, it still needs the rpm or Hz measurement.
Such as http://www.hereticalbuilders.com/showthread.php?t=198

Another variation of prony brake setup/formulas/exmple calculations
http://chestofbooks.com/crafts/metal/Applied-Science-Metal-Workers/48-Another-Form-Of-Prony-Brake.html

I hope this helps.
Mike

[gotoluc]

Sorry Mike,  that's not what I want to do.

Read my reply to vidar (above yours) to better understand.

Luc

[mikestocks2006]

Sorry Mike,  that's not what I want to do.

Read my reply to vidar (above yours) to better understand.

Luc

Ok, if you try to compare the pull force of your solenoid to a the power of an 80%  efficient typical electric motor, the units are incompatible, Newtons not equal to Watts.
The pull force of your solenoid is easy to measure, use simple weights or small kitchen scale.
When you stall a motor by clamping the shaft you measure the stall torque (not force), (also possibly depending on position if the motor has considerable cogging).

Maybe you can compare solenoid to solenoid.
There are standard spec tables out there that maybe of help then:
Check page 6 force vs power graphs for a permanent magnet solenoid as an example
http://www.delta.com.tw/product/cp/solenoid/download/pdf/Solenoids%20catalogue.pdf
For design and comparison to what you have this might help with your calculations.
http://www.daycounter.com/Calculators/Magnets/Solenoid-Force-Calculator.phtml

I hope this helps
Mike