# Help with Motor voltage/torque for 12 Newtons of force...

1. Dec 16, 2015

### Aspirant

Hello all, I'm going to get right to the point!

However, it doesn't work quite as much as I had hoped. You see, it pulls the blade back... but it can't pull it all the way back against the spring's resistance, so is doesn't reload and there still a portion of the blade sticking out of the handle.

So I need a new (bigger) motor that can bring the blade in even in spite of the spring resistance. I decided I would measure the exact force it takes to completely close the spring, and I discovered it takes approximately 12 newtons of force. Unfortunately I haven't found anything on the web that can translate that into what sort of motor voltage or torque I would need to reach that amount of force.

What sort of advice to you guys have for me?

-Aspirant

2. Dec 16, 2015

### Staff: Mentor

Mechanical advantage, as in gears or pulleys, can multiply the force at the expense of speed.

3. Dec 17, 2015

### jim hardy

even just wrapping the string around a smaller pulley.

4. Dec 17, 2015

### Aspirant

Is there anyway that I could get a superior motor without having to throw gears and such into the system? Or is there no small sized motor with that kind of power?

5. Dec 17, 2015

### Staff: Mentor

What kind of power do you mean? It's hard to answer your question because you don't say how much power you have or how much you need.

6. Dec 17, 2015

### rbelli1

Ditch the spring and make the motor do both actions.

BoB

7. Dec 17, 2015

### CWatters

To work out the power you need to know the pulley diameter and rpm in addition to the force.

8. Dec 17, 2015

### rbelli1

How many sections is the "blade" constructed from?

BoB