Mechanical System Efficiency Lab
Our Winch
What we did here was had a battery plugged together with cables. The cables ran from the battery to the a switch located on the opposite side of the board. Our cables then ran from the switch to the motor which was placed right next to our battery. The motor was made up of gears, and when they turned they also turned the wheel and axel. This lifted the cable, which lifted our weight. All of this had a counterweight on the board, so that our project wouldn't fall off of the table (we didn't have a photograph of the winch on the table). Our battery was calculated to have 8.37V. When we did our experiments with the winch, it ran almost smoothlessly. It lifted the weight up in 3.2 seconds.
Our weight was 200g
The length of the string was 15cm
The measured voltage was 8.37, which we rounded to 8.4V
The time it took to lift the weight was 3.2s
In the picture to the top right hand corner shows our calculations(if you can't read it):
We converted:
15cm to .15m
200g to 1.98N
The measure of our current was 13mA
W=F X d
W=1.98N X .15m
W=.297J
Power of the output=Work/time
Pout=.297J/3.2=93mW
Power of the input=Current X Voltage
Pin=I X V
Pin=.013A X 8.4V
Pin=1.092W
Efficiency%=(Pout/Pin) X 100
Efficiency%=(.093/1.092W) X 100
Efficiency%=(.085) X 100
Efficiency%=8.5%
Our weight was 200g
The length of the string was 15cm
The measured voltage was 8.37, which we rounded to 8.4V
The time it took to lift the weight was 3.2s
In the picture to the top right hand corner shows our calculations(if you can't read it):
We converted:
15cm to .15m
200g to 1.98N
The measure of our current was 13mA
W=F X d
W=1.98N X .15m
W=.297J
Power of the output=Work/time
Pout=.297J/3.2=93mW
Power of the input=Current X Voltage
Pin=I X V
Pin=.013A X 8.4V
Pin=1.092W
Efficiency%=(Pout/Pin) X 100
Efficiency%=(.093/1.092W) X 100
Efficiency%=(.085) X 100
Efficiency%=8.5%
Conclusion
1. List and describe three factors that reduced efficiency in the winch system.
Our biggest problem was friction. We had too much friction in the wheel and axel. Second was the wheel and axel itself, it would wobble and tilt a little bit. Finally the last factor was the battery. It would lose its power after several tries, we could tell because our best result was the first one (which is the try we got most of our measurements.
2. Describe one strategy for making the system even more efficient.
We could've made it more efficient if we gave the wheel and axel a support structure. We also could've used a better wheel and axel by using a different VEX piece.
3. Explain two or more reasons why automotive engineers are concerned with eliminating inefficiency from
vehicles.
Firstly they want people to but their product, and nobody will buy their car if it can't work as efficient as other cars from different companies. Secondly they don't want people getting hurt, so they have to make their vehicle designed with safe control features, and also make it so that the car would function properly wherever it is.
Our biggest problem was friction. We had too much friction in the wheel and axel. Second was the wheel and axel itself, it would wobble and tilt a little bit. Finally the last factor was the battery. It would lose its power after several tries, we could tell because our best result was the first one (which is the try we got most of our measurements.
2. Describe one strategy for making the system even more efficient.
We could've made it more efficient if we gave the wheel and axel a support structure. We also could've used a better wheel and axel by using a different VEX piece.
3. Explain two or more reasons why automotive engineers are concerned with eliminating inefficiency from
vehicles.
Firstly they want people to but their product, and nobody will buy their car if it can't work as efficient as other cars from different companies. Secondly they don't want people getting hurt, so they have to make their vehicle designed with safe control features, and also make it so that the car would function properly wherever it is.