#### h.d

Joined Oct 22, 2007
150
hi,
i work iin treadmill design project
i want to select the motor that i need
so i go to calculate the torque that applied on the motor
i want to know if the weight if the person who use the treadmill is have to take in torque calculations?also the person stand on belt which is over a deck
that mean the man dont make stress in the belt?
i dont know if my question is in the right forums, but i hope u can help me..
and thnks

#### thingmaker3

Joined May 16, 2005
5,083
Motor torque will have to be great enough to overcome the between the belt and the platform. The friction will be greater if the person is heavier.

Think of it this way:
Take a curtain down and drag it across the floor.
Next, put a small child on the curtain and drag it across the floor again.
Next, put a man on the curtain and drag it across the floor again.
Next, put a camel on the curtain and drag it across the floor.

Friction will also depend on the belt design and the platform design.

Take the curtain with the child on it and pull it across rocky ground.
Take the curtain with the child on it and pull it across sand.
Take the curtain with the child on it and pull it across a fine smooth floor.

Try it with a burlap curtain, a wool curtain, and a silk curtain.

#### hgmjr

Joined Jan 28, 2005
9,027
Do you plan to place many rollers beneath the belt on which the individual is standing as a means of cutting down on the friction of the belt?

hgmjr

#### beenthere

Joined Apr 20, 2004
15,819
I have seen a treadmill motor on a surplus site that was rated at one horsepower. that should get you in the ballpark.

#### h.d

Joined Oct 22, 2007
150
Motor torque will have to be great enough to overcome the between the belt and the platform. The friction will be greater if the person is heavier.

Think of it this way:
Take a curtain down and drag it across the floor.
Next, put a small child on the curtain and drag it across the floor again.
Next, put a man on the curtain and drag it across the floor again.
Next, put a camel on the curtain and drag it across the floor.

Friction will also depend on the belt design and the platform design.

Take the curtain with the child on it and pull it across rocky ground.
Take the curtain with the child on it and pull it across sand.
Take the curtain with the child on it and pull it across a fine smooth floor.

Try it with a burlap curtain, a wool curtain, and a silk curtain.
ok sure the weight of the person will effect an increase the friction
but that is relative to the belt material and note that man not stand on the belt only there are deck(wood) or serial of rollers that carry the belt.

#### h.d

Joined Oct 22, 2007
150
Do you plan to place many rollers beneath the belt on which the individual is standing as a means of cutting down on the friction of the belt?

hgmjr
yes that what i done in my mechanical design
that rollers i think that will estimate the friction effect
but the weight of person should effect....but how much that factor is important i want to know?

#### h.d

Joined Oct 22, 2007
150
I have seen a treadmill motor on a surplus site that was rated at one horsepower. that should get you in the ballpark.
the power range is start from 0.75hp to 4hp
but i have to calculate the wanted power
i hope my machine able to up person with 80kg
i want to decrease the hp as can i to decrease the cost of project
as the power down the current decrease.

#### thingmaker3

Joined May 16, 2005
5,083
yes that what i done in my mechanical design
that rollers i think that will estimate the friction effect
but the weight of person should effect....but how much that factor is important i want to know?
Won't rollers on the platform be uncomfortable to the user? And wouldn't each roller have to support the 80Kg of the user?

And what about us fat people? I'm a full 100Kg. I think I need my treadmill a bit more than some skinny little 80Kg kid! My treadmill can handle persons up to 140Kg. 3Hp motor. The belt has ribs on the inside which slide along a teflon-surfaced platform.

As with most tools, cutting corners leads to inferior performance.

And weight does indeed play a role in friction! See my examples above. Or read this: http://en.wikipedia.org/wiki/Normal_force