Belt Drive Question about pulleys

[satguy]

I have a quick question that im hoping someone can help me with.

On a 1:1 ratio belt drive system. will a larger pulley size place a larger load on the motor?
for example if i used 32 teeth pulleys instead of the smaller 15 teeth pulleys will my nema 17 motor have to work harder to drive it?

[ger21]

Is it just a belt reduction to turn a screw? If so, then the only issue would be inertia from a larger diameter. If the pulleys are heavy, than it would take more torque to accelerate at the same speed. If they are plastic, it probably won't make much difference.

[satguy]

thanks Gerry
the belt is not driving a leadscrew. its driving a linear rail.
the belt is attached to the linear bearing moving it left and right. On the left hand side of the rail i have the motor and driver pulley. on the right i have the idler/tentioning pulley.

i just thought that it would take more torque to move a larger pulley since the motor must move at a slower pace to achieve the same speed using a larger pulley. Is this right when ignoring pulley weight?

[ger21]

In that case, then it will need more torque. Say you have a 100 oz-in motor. With a 2" diameter pulley (1" radius), you can pull (more accurately hold) 100 oz's.

Divide the motor torque by 1/2 the pitch diameter to get the force applied.