Motor torque

[shiloh]

Hi there

I need to calculate motor speed and reduction on a drive wheel.

the wheel is 2" diameter and is pulling a wire that is pinched between it and another roller. I'll need 100lbs of pull on the wire. I'll need to pick a dc motor and reducer to get this and we already got it wrong once...

[Kelly_Bramble]

Motor torque minimum = 100lbs x 2" = 200 lbs-in.

With a 3:1 factor of safety you will need 600 lbs-in motor.

[shiloh]

Thanks. Will speed be a factor? Ill want to run that at 200 rpm.

[Kelly_Bramble]

Thanks. Will speed be a factor? Ill want to run that at 200 rpm.

Yes, you need motor that is torque rated at that rpm or gear it to perform optimally.

[jboggs]

Motor torque minimum = 100lbs x 2" = 200 lbs-in.

With a 3:1 factor of safety you will need 600 lbs-in motor.

Kelly,
The wheel is 2" diameter. Wouldn't the moment arm be 1"? So the calculation is 100 lbs x 1" = 100 lbs-in?

[Kelly_Bramble]

Kelly,
The wheel is 2" diameter. Wouldn't the moment arm be 1"? So the calculation is 100 lbs x 1" = 100 lbs-in?

Yes, you're right.. hope the op caught my mistake