Spring Coupling

[MarkE]

A huge rotating wheel will have tremendous moment of inertia.  Hence once you set a huge wheel in rotation,  force to be applied on its outer edge to keep it rotating will be negligible.

You are conflating temporarily consuming stored kinetic energy with torque transfer.

The tension developed in spring will be corresponding to this force only.  So, tension developed in spring and energy consumed for tensioning the spring are also negligible.  This will be taken care of by mechanical advantage.

Wrong.  The tension in the spring is a result of the reflected load torque.  Over time the power contributed by a finite energy store such as the maximum energy that the spring can store or the flywheel can store approaches zero. 

What for this forum is there?   What for "half baked ideas"?

The idea is dead on arrival because it relies on non-physical concepts.

 
That happens only in case of rigid coupling.

Again that is wrong.  The compliance of the coupling sets a maximum variation, and combined with the inertia sets a time constant.  Averaged over many time constants, the torque is the same as with a rigid coupling.

If you tie a meter length rope to a pillar and apply tangential force at the end of the rope,  will the tangential force depend on the radius?  Whatever force you apply at the edge of the rope,  same force appears at the outer edge of the pillar. 

I see you appear to be very confused about where the forces originate.   If you apply a linear tangential force out at some moment arm as in your pillar example then the torque depends on the radius.  A rotating device such as a motor develops a torque, not a linear tangential force.  A generator reflects a torque, not a linear tangential force.

For rigid coupling  F(tangential) generator is less than F (tangential) motor depending on radius.

Both the motor and the generator operate on torque.  The spring transfers torque.  The tangential forces depend on the radii.

For spring coupling F (tangential) generator  =  F (tangential) motor,  doesnot depend on radius.   Hence torque will be magnified.

No dude,  see as I have explained.  If I have an 1800 rpm 1 hp motor, that motor turns 188.5r/s and produces a torque of 3.96 N*m.  Tangential force, not the torque depends on the radius.  Ditto a generator that produces 1hp*efficiency output at 1800 rpm.

[MarkE]

It needs to hold against the torque.  A rigid coupling is nothing more than a spring with a very high K.

[vineet_kiran]

If the thought is that if I pull on one end of a clock spring with 1lb of force then the other end of the clock spring needs to hold against that force, and if the length of arm connecting the two ends are not the same then the resulting torque on the output side will be higher,, sound enough except for the change in direction, or angle, of force as it is transferred through the spring,, the ends, in this case, end up pulling in towards each other as well as a tangential force against the ends of the arms.

I say this because I actually built this about a year ago,, and noticed that the end connections would rotate as force was applied pointing towards the true direction of applied force.

You are exactly right.  The force appearing on generator flange depends on direction or angle of application of force from the spring.  To overcome this problem you may have to use several springs one above the other with their ends terminating at equidistances on respective flanges.

For example if you use four springs, their ends should terminate at 90 degrees apart on respective flanges. You know about this because you have conducted the experiment.  It is difficult argue with people who simply talk without practical knowledge.

No dude,  see as I have explained.  If I have an 1800 rpm 1 hp motor, that motor turns 188.5r/s and produces a torque of 3.96 N*m.  Tangential force, not the torque depends on the radius.  Ditto a generator that produces 1hp*efficiency output at 1800 rpm.
   

The torque developed by a 1 HP motor depends on its internal characteristics such as internal diameter of the rotor, strength of electromagnetic forces etc.   The torque you get at the motor shaft is a result of these internal characterisics.

But if you fix a lengthy lever arm to the motor shaft,  even a little child can hold this lever arm and prevent 1 HP motor shaft from rotating.  If you tie a lengthy rope instead of a lever arm,  even a adult cannot prevent motor shaft from rotating because force doesnot get magnified through rope since it is not rigid.

Through your postings I can make out that you are a superficial crank.  Too much book reading without practical knowledge makes a superficial crank.

Take examples of Farday, Newton, Edison  etc.,  I think none of them had academic carreer.

[MarkE]

The torque developed by a 1 HP motor depends on its internal characteristics such as internal diameter of the rotor, strength of electromagnetic forces etc.   The torque you get at the motor shaft is a result of these internal characterisics.

Those characteristics are how the motor gets its 1hp rating.

But if you fix a lengthy lever arm to the motor shaft,  even a little child can hold this lever arm and prevent 1 HP motor shaft from rotating.  If you tie a lengthy rope instead of a lever arm,  even a adult cannot prevent motor shaft from rotating because force doesnot get magnified through rope since it is not rigid.

And in that you have just confirmed that the tangential force is as I have been telling you the motor torque divided by the length of the moment arm.  The torque into the spring does not depend upon the flange plate or spring diameters.  You have now eviscerated your own postulate.

Through your postings I can make out that you are a superficial crank.  Too much book reading without practical knowledge makes a superficial crank.

Take examples of Farday, Newton, Edison  etc.,  I think none of them had academic carreer.

Ad homs on top of destroying your own argument don't speak well for you.

[MarkE]

Tom, sure you can do those things.  However, over time you can't either keep winding up the spring indefinitely, nor can you unwind it indefinitely.  Over time the average amount of wind-up or relaxation on a per rotation basis tends towards zero.  That means that on average the amount of power that the spring stores or releases tends towards zero.  On average the spring just conveys power from the motor to the load (generator).  The input power is the motor torque multiplied by the shaft speed.  That same power, ignoring losses, conveys from one end of the spring to the other.