Stepper motor torque help

Thread Starter

GarrettVD

Joined Apr 13, 2013
10
Hi all,
I am building an automated homebrew system, and I am looking for a proper stepper motor that fits the bill. I've done the force calculations myself, but I am no expert when it comes to physics and motors. Am I correct in believe that, if I have a 40lb mass that I need to raise and lower, using a 4" diameter pulley, that I will require a stepper motor with 80lbf/in torque? Also, if anyone can PM me some websites to find a motor that would fit the bill, that would be great as well.

Cheers,
 

Thread Starter

GarrettVD

Joined Apr 13, 2013
10
With such a heavy load any direct drive motor would have to be very large.
You need a reduction gear in order to lift 40lb.
Thanks, Mr. Chips. So, after a bit of research on gear ration, am I correct in thinking that if I have a 2" radius driving cog, and a 4" radius follower cog, the amount of force exerted by the follower cog is double; while the rpm would be 1/2 of the original rpm?
 

MrChips

Joined Oct 2, 2009
30,618
Look into a worm gear if you want it to be self locking, i.e. the load cannot fall back down when the motor stops.
 

THE_RB

Joined Feb 11, 2008
5,438
Maybe you could use a threaded rod and a nut? A threaded rod with pitch less than 2mm is common, and with a typical size-23 stepper motor should easily produce linear force of 150-200 kg (300-400 lb).
 

Rbeckett

Joined Sep 3, 2010
208
Motiontek.ca has steppers and drive components. I am using quite a bit of their stuff on my three tier tower and control system. I am using pneumatics to dump the HLT and DS18B20's as temp sennsors for my PID's. I am driving all of the electronics from a 12VDC, 5A PS and several AC/DC SSR's. Eventually I will automate the valves to better manage my fluid circuit as well as the over all brew cycle. Good luck, an how about some pics of you tower too.

Bob
 
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