# Timing Pully&Belts - Adding another to help?

1. Feb 1, 2014

Timing Pully&Belts -- Adding another to help?

I am working on a project at my University. It's extra-curricular and not homework related. At the end we will give a report on what we learned during the development. Our team is working on some ideas for a basic robotic climber, that climbs a cable (similar to a seatbelt).

As you can see in the picture below, we are using a timing pulley to transfer power to the driven wheel which will "pull" the climber up the cable.

The motor we chose is the "Mabuchi RS-540RH"
http://www.mabuchi-motor.co.jp/cgi-bin/catalog/e_catalog.cgi?CAT_ID=rs_540sh
--@ No-Load, it is rated to run at 23,400[rpm].
--@ Stall, (shaft stops turning), the rated Stall Torque is 0.196[Nm]

The small pulley (1, see pic below) turns at a 20.25:1 gear reduction ratio, so:
--Stall Torque: 3.969[Nm]

①: What is the "Design Power" for the small pulley?
---P=T*ω (Torque * Angular Velocity)
---Design Power=P*k0
(k0 is like 1.5 for our applications)
For this equation, do you use Stall Torque for Torque, and No-Load Speed for RPM? We haven't timed to see how much power it drains and how many RPMs we get yet. But there should still be a way to calculate the Max Power that could be put out at the small pulley, right?

②：This one should be a little easier. As in the Picture below, if we added another two pulleys and belt, exact same as the ones there already, would this separate the stress on the belt by half, so it could take more torque before stretching or skipping?

Here is the picture:
https://fbcdn-sphotos-h-a.akamaihd.net/hphotos-ak-ash4/t1/1002325_10202958579628311_1866036584_n.jpg