A gear train is two or more gear working together by meshing their teeth and turning each other in a system to generate power and speed

• It reduces speed and increases torque
• Electric motors are used with the gear systems to reduce the speed and increase the torque

Types of Gear trains

1. Simple gear train
2. Compound gear train
3. Planetary gear train

1. Simple Gear Train

• The most common of the gear train is the gear pair connecting parallel shafts. The teeth of this type can be spur, helical or herringbone.
• Only one gear may rotate about a single axis

2. Compound Gear  trains

• For large velocities, compound arrangement is preferred
• When there are more than one gear on a shaft,it is called a compound gear trains.
• Two or more gears may rotate about a single axis

3.Planetary Gear trains

Epicyclic gearing or planetary gearing is a gear system consisting of one or more outer gears, or planet gears, revolving about a central, or sun gear. Typically, the planet gears are mounted on a movable arm or carrier, which itself may rotate relative to the sun gear.

• They have higher gear ratios.
• They are popular for automatic transmissions in automobiles.
• They are also used in bicycles for controlling power of pedaling automatically or manually.
• They are also used for power train between internal combustion engine and an electric motor.