Atwood Speed help

[Al Skierkiewicz]

Originally Posted by psychoCHIPMUNKK

I’m planning on using an Atwood in an Inventor model that I’m doing for my engineering class and I came across a question; The spec sheets have "Normal load" in the performance chart, but what is normal load?

Chip,
The "normal load" is usually a reference for that motor only. There is no standard load for motors but there is a standard method for testing motors. It would help if you post the site you are referencing so everyone could see what we are discussing. The normal load for this motor likely refers to the fact that it is designed to be used with a trailer jack. The specifications for the weight range of trailers is likely what the sheet is referring to and that takes into account the gearbox to which the motor is coupled.
If you look at just the motor curvesor charts, you will see that there is a distinct correlation between motor speed, power out, torque, current and efficiency. A designer will perform black magic as he/she chooses where on the chart to operate. A low a speed will increase torque but sacrifice efficiency and raise current. A high speed will sacrifice torque but minimize current. Somewhere in the middle will optimize all of the factors, giving reasonable speed, torque and output power while using acceptable currents. Paul Copioli might be a better one to jump in here and explain. You might try searching his posts and see if he hasn't already posted an explanation on this.