Conical Pulley Drive results in overunity?

[vineet_kiran]

 


Any comments?

[MarkE]

The cone hurts efficiency.   The upper part of the belt is under high tension going around the pulley, while the bottom is in low tension.  Consequently, as any portion of the belt approaches  the pulley, work is done in the vertical axis of the belt as the upper portion has to stretch more than the bottom portion.  As that particular portion of the belt travels around the pulley that tension is released.  The portion work performed on the vertical axis of the belt is orthogonal to the direction of motion and does not contribute to it.   That work just heats up the belt.

[vineet_kiran]

The cone hurts efficiency.   The upper part of the belt is under high tension going around the pulley, while the bottom is in low tension.  Consequently, as any portion of the belt approaches  the pulley, work is done in the vertical axis of the belt as the upper portion has to stretch more than the bottom portion.  As that particular portion of the belt travels around the pulley that tension is released.  The portion work performed on the vertical axis of the belt is orthogonal to the direction of motion and does not contribute to it.   That work just heats up the belt.

I don't think it is a serious issue.  Actually tension in belts is one of the required parameters for transmission of power using belts.  If belt is loose,  then pulley will slip under the belt and power transmission will not be effective.

You have to choose suitable belt material.  You can even make top and bottom portion of belt with different material having
different elastic properties and join them with belt clips or industrial adhesive.  May be it will be a material science or design problem.
 
When output power is far more than the input power you can readily sacrifice a small portion power for tensioning the belts.

[MarkE]

I don't think it is a serious issue.  Actually tension in belts is one of the required parameters for transmission of power using belts.  If belt is loose,  then pulley will slip under the belt and power transmission will not be effective.

You have to choose suitable belt material.  You can even make top and bottom portion of belt with different material having
different elastic properties and join them with belt clips or industrial adhesive.  May be it will be a material science or design problem.
 
When output power is far more than the input power you can readily sacrifice a small portion power for tensioning the belts.

Static tension does not contribute to power loss.  Dynamic stretching and relaxation do.  Modern drive belts are reinforced with high tensile strength fibers to limit stretching. 

You have not presented any basis for the output power to exceed the input power.  You have introduced additional and unnecessary loss to a simple mechanical drive.  The conical arrangement is really bad.  It harms the efficiency.  It does not create energy.

[vineet_kiran]

Static tension does not contribute to power loss.  Dynamic stretching and relaxation do.  Modern drive belts are reinforced with high tensile strength fibers to limit stretching. 

High tensile fibres are used to strengthen the belt.  If  belt doesnot have tension how it will transmit power?   If belt is stretched too much it becomes loose after sometimes and you may have to scrap the belt.  This is just a material or design problem and problem with working principle.  Working principle here is that switching between speed and torque using different sizes of pulleys conneted by a belt.

You have not presented any basis for the output power to exceed the input power.  You have introduced additional and unnecessary loss to a simple mechanical drive.  The conical arrangement is really bad.  It harms the efficiency.  It does not create energy.

Please read the attachment again.  In that I have mentioned why I expect output power to be more than input power.  If it is wrong please tell me why it is wrong.  Please don't talk BS.   
Any problem with stretching or tension of belts can be solved suitably.    The question here is that whether output torque is more than input torque.   It has to be so because of difference in diameters.