Which input component tends to produce forward overdrive rather than forward reduction when other components are fixed?

Which input component tends to produce forward overdrive rather than forward reduction when other components are fixed?

• A. Ring gear
• B. Sun gear
• C. Carrier
• D. Held

Answer: (C)

In an epicyclic (planetary) gear set, the carrier acts as a speed multiplier because driving it forces the planet gears to both spin on their own axes and revolve around the sun. When the other components are fixed, this dual motion adds up and pushes the output speed higher than the input, giving forward overdrive. If instead you drive the sun or the ring while the others are fixed, the motion is constrained to a single path, which tends to produce a slower output relative to the input (forward reduction).

In an epicyclic (planetary) gear set, the carrier acts as a speed multiplier because driving it forces the planet gears to both spin on their own axes and revolve around the sun. When the other components are fixed, this dual motion adds up and pushes the output speed higher than the input, giving forward overdrive. If instead you drive the sun or the ring while the others are fixed, the motion is constrained to a single path, which tends to produce a slower output relative to the input (forward reduction).