Fernando`s Force multiplier

[Honza]

Now what is surely puzzling to me is for the 'flag' --- if the big disc is about 8 inches dia of 1/2 inch plate and the small discs are about 5 inches of 3/4 inch plate the total weight is say 13 pounds. !3 pounds on a 18mm rod would last about 5 minutes at 1600 RPM before being flung across the room???

This may be a counter-intuitive issue. When you think more about it - for a disk/weight of a given mass more flimsy the rod/shaft - less movement is transferred into the disk/weight due to the ease of deflection. So paradoxically reducing the stiffness of the rod should lead to a situation in which the disk weight would  hardly move at all (at a given speed), while effectively opposing the oscillating forces produced by the moving link/arm.
And looking at it from a different angle - for a rod/shaft of a given stiffness one can achieve the same by increasing the mass of the disk/weight.

This could take quite a bit of experimenting to achieve, unless somebody knows how to calculate it (I don't)

[vince]

I_ron

If you still have your Force multiplier and it can be repaired I suggest you try a higher rpm motor or a variable speed one. I think you will be pleasantly surprised.

While I was working on a different project I cobbled together a small version of the multiplier. I am using a small dc motor,
with 8 and 10 inch cast iron sheaves for drive and flywheels. The shafts are just 3/4 inch shafting and the offset on the cam drive is 3/4 inch. When I first started it , it would vibrate and shake badly, however after it got past resonance it smoothed out like it wasn't even there.  The picture I took below has the motor spinning at 2300 rpm and the secondary flywheel at 1300 rpm. Like yourself I do not claim there is or is not any advantage to the system . Need to test a few things.  I did not mount any pendulum on it as my tie rod is quite short.  I may make a larger version if this thing pulls any kind of load.

Vince

[caccr2000]

http://www.youtube.com/watch?v=aHk74ufdW7g&feature=player_embedded

http://www.youtube.com/watch?v=tU2x8kREf0M&feature=player_embedded

http://www.youtube.com/watch?v=Tq4Jc-YLbYc&feature=player_embedded

http://www.youtube.com/watch?v=yiZ-Pmk4sXM&feature=player_embedded

[i_ron]

I_ron

If you still have your Force multiplier and it can be repaired I suggest you try a higher rpm motor or a variable speed one. I think you will be pleasantly surprised.

While I was working on a different project I cobbled together a small version of the multiplier. I am using a small dc motor,
with 8 and 10 inch cast iron sheaves for drive and flywheels. The shafts are just 3/4 inch shafting and the offset on the cam drive is 3/4 inch. When I first started it , it would vibrate and shake badly, however after it got past resonance it smoothed out like it wasn't even there.  The picture I took below has the motor spinning at 2300 rpm and the secondary flywheel at 1300 rpm. Like yourself I do not claim there is or is not any advantage to the system . Need to test a few things.  I did not mount any pendulum on it as my tie rod is quite short.  I may make a larger version if this thing pulls any kind of load.

Vince

Good work Vince, I like it. I will keep this on the burner still, nice build. When you say 3/4 of an inch is that 3/4 total with 3/8 offset?


Ron

[vince]

@ i_ron

Thanks.

No, the shafts are 3/4 dia. and the offset from the centerline of the shaft to the centerline of the cam pin (SHAFT) is 3/4"

In my opinion from watching this thing run it seems that basically it is a way of ( pumping) the secondary shaft and flywheel weight via the the cam and link.  To me it seems that the gain comes from the flywheel effect after it reaches its rpm range.  I tried different flywheel sizes and it definitely needs the weight to operate. It would just jam up if no flywheel is on it. When you turn off the power to the motor the things runs on and on because of this effect from the secondary shaft.  Once it gets to it's smooth operating range you can reduce power to the motor and the machine continues at the set speed.  Looking at the chart with that picture of Fernando's multiplier it seems that gain is most prominent at high rpm, much as a flywheel would do.

Going to try and put some load on it to see if it helps to have the multiplier attached.

Vince