×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

DC motor modelling to drive a ship propeller

DC motor modelling to drive a ship propeller

DC motor modelling to drive a ship propeller

(OP)
Hi There,

I want to mathematically model a DC motor connected to a ship propeller through shaft but i am very confused because of the load torque.

I am using the following block diagram to model my motor. Is the load torque is the propeller torque ?? or the motor torque should be equal to the required propeller torque and the load torque in the block diagram should be zero ??



Many Thanks in advance

RE: DC motor modelling to drive a ship propeller

Tl is load torque and is propeller torque. J and B are values of motor (rotor) itself.
Model of load (propeller), to obtain Tl at any speed (from allowed range) it's another task, maybe much difficult.

RE: DC motor modelling to drive a ship propeller

(OP)
Thank you for your kind reply.
I can calculate load torque (propeller torque) but how will we take moment of inertia (J) of the propeller and the shaft into consideration ??

RE: DC motor modelling to drive a ship propeller

??? It is in the denominator of the last block (the FIO that calculates w from net T). That is how the total moment of inertia is taken care of.

Or are you asking us how many kgm2 that moment of inertia is? We cannot know. You've got the dimensions and the specific gravity of those parts.

Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

RE: DC motor modelling to drive a ship propeller

(OP)
So @ Skogsgurra J and B in the last block are not only for the motor but for the load as well. am i right ?
J total = J motor + propeller + shaft ???

RE: DC motor modelling to drive a ship propeller

Yes, J and B are total values reported to motor shaft. Sorry for my mistake in previous post.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources