Ratio = number of teeth on the output gear B (30)
number of teeth on the input gear A (10)
Therefore the ratio is written down as 3:1
The first figure (3) refers to how many turns the input gear (1) must turn in order to rotate the out put gear 1 full revolution.
Simply divide the amount of teeth from the input by the output gear to work out the ratio.
The principle behind gears is also very simple. In the above example, for every complete revolution of the input gear the out put turns 1/3 of the way round. This means you are slowing down the action and are referred to in engineering terms as “Stepping Down”. If we reverse everything then the opposite happens and we “Step Up”. It takes 1 turn of the input gear to turn the output gear 3 revolutions and the ratio is now 1:3.
Stepping down has the advantage of producing more power although it is at a slower rate.
Stepping up produces a much faster output speed, but mechanically delivers less power.
Method
- Firstly, I had counted the number of Cogs on both the large and the small gears.
- Secondly / Lastly, I had counted the number of times the smaller gear system rotates within the larger gear system, which turns Anti- Clockwise once.
Equipment
- Gear system (On the wood).
- Pen, ruler & Paper.
- Table (Table was used as a rest while counting the number of Cogs).
Safety
There was only one safety issue to be observed while conducting the experiment which was to make less noise, as there were other groups too accomplishing the experiment.
Fair Test
While accomplishing the experiment there was only one variable which was kept the same every time? This was the direction of the teeth in the larger gear. It was always kept as one, while carrying out the experiment.
I had used the formula given below to work out my results-
Number of teeth on the Output gear B
Number of teeth on the Input gear A
Results
Conclusion
I think this experiment was successfully accomplished. I had not observed any difficulty while carrying out the experiment. The equipment I was using was accurate which lead me to gain accurate results. From this experiment I have found out that-
- I could find out any gear ratio by dividing the Output gear by the Input gear.
- I also learnt a lot about gears and how they work.
- Lastly, I have learnt the important formula’s in the experiment.
Vocational Aspects
Gears, in industries, are used in tons as mechanical devices. The carry out several important jobs, but most importantly, they provide a gear reduction in motorized equipments. This is important because even a small motor spinning fast, can provide power but not enough torque* (Force). For instance, an electric screwdriver has a large gear reduction because it needs a lot of torque** at a high speed. With a gear reduction, the output speed can be reduced while the torque* is increased. Gears also adjust the direction of rotation.
Important Ratios
Mechanical Advantage = Load / Effort.
Velocity Ratio = Distance moved by the Effort / Distance moved by the Load.
Efficiency (%) = Mechanical Advantage / Velocity Ratio X 100.
*Torque = Force
