Speed reducer question

[Jflip2018]

I'm curious is there is any difference in torque with the Techsew speed  reducer being a 6" pulley and the SR-2 speed  reducer being  9"?    Any help is appreciated! 

Edited May 22, 2018 by Jflip2018

[bullmoosepaddles]

The unit that gives you the greatest reduction will produce the most torque. All other variables being equal.   

[Jflip2018]

Thanks, I guess I should have added that both reducers will get me to 1/3 ratio.  The only difference is the size of the pulleys. 

[koreric75]

6 hours ago, Jflip2018 said:

Thanks, I guess I should have added that both reducers will get me to 1/3 ratio.  The only difference is the size of the pulleys. 

I don't understand how both will get you to 3-1?... Unless you have different pulleys for the drive motor or machine.

 

[Jflip2018]

Techsew's reducer has a 2" and 6" wheels creating a 3:1 ratio and the SR-2 has 3",6" and 9" wheels getting you a 2:1 or 3:1 ratios.

[koreric75]

Gotcha, I'm tracking on the different sizes on the same pulley, but I don't see how that matters unless you factor the motor pulley and machine handwheel pulley... Torque wise..

Like @bullmoosepaddles stated all other variables remaining constant the larger pulley should give you the slower speed, higher torque, which was your original question, right? 

For Max torque I'd venture a small motor pulley to the 9"speed reducer pulley then to a larger or equal size handwheel pulley.... Depending on the machine's pulley if there is a large Delta in price between the two you could go small motor pulley, 6" reducer pulley provided the handwheel pulley is large enough it you can reduce the size of the motor pulley enough to get to the same speed/torque as the 9"speed reducer.

[Jflip2018]

Thanks for the input! 

[CowBoyOUTLAW]

You can find 3 different speed reducer for leather sewing machine and upholstery sewing machine, for both cylinder bed machine and flat bed sewing machine.

http://www.cowboysew.com/product911.htm

 

[plinkercases]

TechSew has a speed reducer which is 154 CND which interestingly enough is more than half the cost of the servo motor and is just passive metal parts. I think buying parts and making one is a more cost effective way to go for me.

[DonInReno]

One advantage to larger pulleys, given identical reduction, is better traction on the belt - so belt tension isn't as critical.