Q3.10: Power Calculation w/ Reduction Gear

[Suman_babai]

Homework Statement

: [/B]
Qstn no. 3.10 in the attached image.

[ Moderator note: Copy of relevant portion of attachment inserted to make it visible here]

Homework Equations

: For power calculation, [/B]
Power = torque * angular velocity... Also, reduction gear is used to deliver lower outout speed at samd torque.

The Attempt at a Solution

: [/B]
I hav tried the above equations and also correctly calculated the 1st ans(2nd attachment) but I can't calculate the 2nd and 3rd ans... I hv approached the second one but ans is not matching.. pls help... also please explain it.. as i am very weak in it...

 

[BvU]

Hello Suman,

why not use the same expression for b) as you use for a) ? You have $\tau$ and you have $\omega$ !

 

[Suman_babai]

Hello Suman,

why not use the same expression for b) as you use for a) ? You have $\tau$ and you have $\omega$ !

Yes.. but.. what is the value uf torque here ?

Hello Suman,

why not use the same expression for b) as you use for a) ? You have $\tau$ and you have $\omega$ !

Yes I know. But how can I get the torque? If it is the resisting torque of water, then where goes the torque given by the turbine shaft ? Or will it be the difference between the above mentioned torques ?

 

[BvU]

If it is the resisting torque of water

For want of better you could start with that assumption ...

where goes the torque given by the turbine shaft

That is a nice subject for part (c)

 

[Suman_babai]

For want of better you could start with that assumption ...
That is a nice subject for part (c)

Ok I get the 2nd prt... and also the 3rd prt... thnks a lot.. but what is the significance of the 3rd part?

 

[BvU]

It's a giveaway: subtract 14.235 from 15. Too easy ! But it shows the gearbox needs cooling

 

[Suman_babai]

It's a giveaway: subtract 14.235 from 15. Too easy ! But it shows the gearbox needs cooling

Yes I know the mathematical prt. I jst wanted to know to know its significance... thank you very very much.