# How to find torque on planet carrier

1. Jan 12, 2014

### csiddharthn

I have the following data in an epicyclic gear train:

Angular speed on ring = 1500 rpm, teeth on ring = 30
Angular speed on sun = 3200 rpm, teeth on sun = 10
Angular speed on carrier = 1925 rpm, teeth on planets = 10

(The ratios of teeth are for simple calculation assumed 3: 1: 1 among ring, sun and carrier.)

Now,

torque on ring = 190 Nm
torque on sun = 50 Nm

How do I find the torque on the planet carrier?

2. Jan 13, 2014

### moogull

Hi Csidd,

A question for you; when you mention that there are torques on the ring and sun gears, does this mean that they are the two inputs to the system and that the carrier is the output? If so I think you can use a power balance. Ideally, power out = power in. Not ideally, power out = efficiency*power in. Also, can you specify the directions of the rotations?

3. Jan 13, 2014

### moogull

4. Jan 13, 2014

### Baluncore

I have not checked your gear ratios and relative RPMs.
Analyse the energy flow per minute.
power = rpm * torque

Wsun = 3200 * 50 = 160 k
Wring = 1500 * 190 = 285 k

The problem is that we do not know the direction of the torque.

There are two possible solutions.
The sum = 445 k
445 k / 1925 = 231. 169 Nm

The difference = 125 k
125 k / 1925 = 64.93 Nm