NEVER be confused by GEAR RATIOS again - EXPLAINED in the MOST VISUAL WAY using LEGO

Summary

This video is a follow-up to a previous one, expanding on the concepts of horsepower and torque using LEGO motors. It explains how torque is a twisting force and how horsepower is the rate of torque over time. The video introduces gears, showing how they manipulate torque and speed. By adjusting the gear ratio, the video demonstrates how a smaller motor can achieve greater torque, but at the cost of speed. It explains the trade-off between torque and speed in gear systems and how gear ratios are applied in vehicles. The video provides a clear, visual explanation of these engineering principles.

Takeaways

• 🔧 Torque is a twisting force, the rotational equivalent of linear force, determining how strong a motor's rotation is.
• 🏎️ Horsepower is the rate of torque or the frequency of torque application, calculated as torque times RPM (rotations per minute).
• ⚙️ Gears can manipulate torque and speed without increasing motor size by adjusting the gear ratio.
• 📏 The gear ratio is determined by dividing the number of teeth on the driven gear by the number of teeth on the driver gear.
• 💪 By using a gear ratio, a smaller motor with lower torque can move heavier loads by increasing torque output, but at the cost of reduced speed.
• 📉 Increasing torque through gears results in a reduction in speed, as demonstrated by the small motor becoming slower after adding a gear system.
• 🔄 Gear ratios like 5:1 increase torque and reduce speed, while smaller ratios increase speed but decrease torque.
• 🚗 Car transmissions use similar principles with lower gears providing more torque for acceleration, and higher gears offering higher speed with less torque once up to speed.
• 🔄 Swapping driver and driven gears changes the effect—reducing torque but increasing speed, or vice versa.
• ⚖️ There’s always a trade-off: increasing torque reduces speed and vice versa, demonstrating the balance required in mechanical systems like cars and motors.

Q & A

What is torque, according to the video?

Torque is described as a twisting force, or the rotational equivalent of a linear force, that determines how strong the rotation of a motor or engine is.

How is horsepower related to torque?

Horsepower is the rate of torque application, and can be calculated as torque times RPM (revolutions per minute).

What was the main difference between the large and small motor in terms of torque output?

The large motor generated 0.14 Newton meters of torque, while the small motor generated only 0.03 Newton meters of torque, meaning the large motor had more strength.

How do gears help increase the torque of the small motor?

By using gears, the torque from the small motor can be multiplied. A smaller gear is attached to the motor, and a larger gear is attached to the heavy arm, increasing the torque output without increasing the motor size.

How is the gear ratio calculated in the video?

The gear ratio is calculated by dividing the number of teeth on the driven gear by the number of teeth on the driver gear. In the example, the ratio is 40 teeth (driven) divided by 8 teeth (driver), which equals 5.

What effect does increasing the gear ratio have on torque?

Increasing the gear ratio increases the torque. In the example, the small motor's initial torque of 0.03 Newton meters becomes 0.15 Newton meters when multiplied by a gear ratio of 5.

Why does increasing torque through gears reduce speed?

Increasing torque through gears reduces speed because a larger gear has a larger circumference, meaning more distance must be covered for each rotation, thus reducing the rotational speed.

How can the new output speed of a motor with gears be calculated?

The new output speed can be calculated by dividing the motor's initial RPM by the gear ratio. For example, 275 RPM divided by a gear ratio of 5 results in a new output speed of 55 RPM.

What happens when the driver and driven gears are switched?

When the driver and driven gears are switched, the output speed dramatically increases while the torque decreases. In the example, the torque is reduced to 0.006 Newton meters, and the speed increases to 1375 RPM.

Why are lower gears in a car's transmission designed to increase torque?

Lower gears in a car's transmission increase torque because more torque is needed to get a vehicle moving from a standstill and to help with acceleration. Once the vehicle is up to speed, less torque is needed, and higher gears prioritize speed.