# Planet gear efficiency. Need help

• anticz
In summary, the conversation discusses the difficulties in determining the theoretical efficiency of a compound epicyclic gear train, which is meant to run at a slow speed and light load. The train has a total reduction of 720:1 and consists of various gears with different teeth counts. The person is unsure of how to calculate the energy loss and torque needed for the train and is seeking help from others. They are considering building and testing the train or looking at similar designs for an estimate.
anticz
I'm having a bit of difficulty figuring out the theoretical efficiency of a compound epicyclic gear train. The math involved is a bit over my head. This train is meant to run at very slow speed under light load. I want to find the theoretical efficiency of the design so I can determine if it is feasible to build. Here are the details.

(A) sun gear = 17 teeth
(B) Planet gear = 51 teeth
(C) Ring gear = 119 teeth
(D) Planet gear = 52 teeth
(E) Ring gear = 120 teeth
.25 module (metric)
input torque = 5 to 10 [N*mm]

Input is Ring (E) rotating counter-clockwise once every 6 hours
Output is Sun (A) rotating clockwise once every 30 seconds
720:1 total reduction

Ring (E) meshes with Planet (D) which is compounded to planet (B). Planet (B) meshes with ring (C) [locked] giving a -90:1 reduction on the arm (Arm spins clockwise). Compound planets spin 2.333333:1 relative to carrier. Planet (B) meshes with Sun (A) giving an 8:1 ratio for a total ratio of 720:1.

I'm guessing this is going to be very inefficient do to the high reduction but, I have no Idea how to find out how much energy is being lost or how to figure out how much torque is actually needed to run this. I've found several methods for calculating efficiency of an epicyclic train but I'm completely lost on this because it's a bit more complex than a simple planet set. I'd describe myself as more of an amateur inventor than a mechanical engineer. Any help would be greatly appreciated.

Mike B.

Build it and test?

Or look at similar designs if you just want a ballpark estimate.

## 1. What is planet gear efficiency?

Planet gear efficiency is a measure of how well a planetary gear system can transmit power from the input shaft to the output shaft. It takes into account factors such as friction, gear design, and material properties.

## 2. How is planet gear efficiency calculated?

Planet gear efficiency is typically calculated by dividing the output power by the input power, and multiplying by 100 to get a percentage. It can also be calculated by comparing the torque on the input and output shafts.

## 3. What factors affect planet gear efficiency?

There are several factors that can affect the efficiency of a planetary gear system, including the number of gears, gear size and design, lubrication, and material properties such as friction and wear resistance.

## 4. How can planet gear efficiency be improved?

There are a few ways to improve the efficiency of a planetary gear system. These include using high-quality materials, optimizing gear design, minimizing friction through proper lubrication and maintenance, and reducing the number of gears in the system.

## 5. Why is planet gear efficiency important?

Planet gear efficiency is important because it affects the overall performance and energy consumption of a gear system. A higher efficiency means less power is lost and more power is transmitted, leading to a more efficient and reliable system.

• Mechanical Engineering
Replies
2
Views
1K
• Mechanical Engineering
Replies
1
Views
1K
• Mechanical Engineering
Replies
9
Views
2K
• Mechanical Engineering
Replies
2
Views
2K
• Mechanical Engineering
Replies
2
Views
1K
• Mechanics
Replies
4
Views
951
• Mechanical Engineering
Replies
1
Views
4K
• Mechanical Engineering
Replies
2
Views
2K
• Mechanical Engineering
Replies
2
Views
3K
• Mechanical Engineering
Replies
24
Views
3K