The document discusses gear ratios and speed ratios in a gear system. It states that the gear ratio is calculated as the number of teeth on the driven gear divided by the number of teeth on the driving gear. For a gear with a 100 tooth driving gear and 25 tooth driven gear, the gear ratio is 1:4. It then states that the speed ratio, which is the speed of the driven gear divided by the speed of the driving gear, will be equal to the inverse of the gear ratio. Therefore, the speed ratio of this system is 4:1, meaning the driven gear speed is 4 times the driving gear speed. It also discusses how power must be conserved between the input and output of a gear system.

1. Shaft 1
Shaft 2

2. Gear 1
No of teeth 100
Gear 2
No of teeth 25

3. 25
100

4. Gear ratio
Gear ratio =
No of Teeth on Driven Gear
No of Teeth on Driving Gear
25
100
= 1 : 4
=

5. Gear ratio
Gear ratio =
No of Teeth on Driven Gear
No of Teeth on Driving Gear
25
100
= 1 : 4
=
• Driven Gear speed is 4 time Driving gear speed

6. Speed ratio
Speed ratio =
Speed of Driven Gear
Speed of Driving Gear
4
1
= 4 :
1
=
• Driven Gear speed is 4 time Driving gear speed

7. Speed ratio =
Speed of Driven Gear
Speed of Driving Gear
4
1
= 4 :1
=
Gear ratio =
No of Teeth on Driven Gear
No of Teeth on Driving Gear
25
100
= 1 : 4
=
Speed ratio is inverse to Gear ratio
Speed ratio =
Gear ratio
1

8. Speed of Driven Gear
Speed of Driving Gear
No of Teeth on Driven Gear
No of Teeth on Driving Gear
Speed ratio is inverse to Gear ratio
Speed ratio =
Gear ratio
1

9. Speed of Driven Gear
Speed of Driving Gear
No of Teeth on Driven Gear
No of Teeth on Driving Gear
Speed ratio is inverse to Gear ratio
Speed ratio =
Gear ratio
1
1
=

10. Speed of Driven Gear
Speed of Driving Gear No of Teeth on Driven Gear
No of Teeth on Driving Gear
Speed ratio is inverse to Gear ratio
Speed ratio =
Gear ratio
1
1
=

11. Speed of Driven Gear
Speed of Driving Gear No of Teeth on Driven Gear
No of Teeth on Driving Gear
Speed ratio is inverse to Gear ratio
Speed ratio =
Gear ratio
1
=

12. Power : Joule / sec
Time
Energy

13. Power at Input, Driving Gear = Power at Output, Driven Gear

14. Power = Torque X Angular speed

15. Power at Input, Driving Gear = Power at Output, Driven Gear
=
Torque of Driving gear Speed of Driving Gear Torque of Driven gear Speed of Driven Gear
X X
=

16. Power at Input, Driving Gear = Power at Output, Driven Gear
Speed of Driven Gear
Speed of Driving Gear
Torque of Driven Gear
Torque of Driving Gear
=

17. Speed of Driven Gear
Speed of Driving Gear No of Teeth on Driven Gear
No of Teeth on Driving Gear
Speed ratio is inverse to Gear ratio
Speed ratio =
Gear ratio
1
=

18. Speed of Driven Gear
Speed of Driving Gear
=
No of Teeth on Driven Gear
No of Teeth on Driving Gear
Torque of Driven Gear
Torque of Driving Gear
=

19. Speed of Driven Gear
Speed of Driving Gear
=
No of Teeth on Driven Gear
No of Teeth on Driving Gear
Torque of Driven Gear
Torque of Driving Gear
=