If the carrier is the held or reaction member of the gear set, then the results will always____________.

If the carrier is the held or reaction member of the gear set, then the results will always____________.

• A. a forward reduction ratio
• B. reverse
• C. a forward underdrive ratio
• D. a forward overdrive ratio

Answer: (B)

In a planetary gear set, the direction of output depends on which member is held fixed. When the carrier is held, the planet gears are locked in place relative to the carrier, so the sun and ring gears must move in opposite directions to keep their teeth in contact. Because the input motion is transmitted through the gear mesh to the other outer gear via the planets, the output ends up turning opposite to the input. So, with the carrier as the held member, the output will rotate in the reverse direction relative to the input.

In a planetary gear set, the direction of output depends on which member is held fixed. When the carrier is held, the planet gears are locked in place relative to the carrier, so the sun and ring gears must move in opposite directions to keep their teeth in contact. Because the input motion is transmitted through the gear mesh to the other outer gear via the planets, the output ends up turning opposite to the input. So, with the carrier as the held member, the output will rotate in the reverse direction relative to the input.