×
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

Determine Centifugal Compressor Torque

Determine Centifugal Compressor Torque

Determine Centifugal Compressor Torque

(OP)
Hello,
If I have a compressor with known speed and gas power required, can I simply use those two parameters to calculate the torque required.  I.e. Torque = power/angular velocity.
Can I further use the fan laws to calculate the power and therefore the torque at lower speeds which would give me an (inaccurate) estimation of the start-up torque of the compressor?
Query relates to a problem motor starting torque with a 7.9MW motor driven compressor, my electrical mates have worked out the motor available torque. There is also a 10:1 gearbox in the string.

Thanks

RE: Determine Centifugal Compressor Torque

(OP)
In answer to my own question (i've been swotting up).
Calculating the torque by this method is correct but cannot be used to give an accurate start-up curve because it is based on rated conditions.  However during start-up the system may have been partially or fully blown down, regardless the compressor will be started on recycle so the 100% speed power will be the recycle power.

If anyone has got anything else to add or knows any programs avaiable to verify vendor produced curves I'd much appreciate it.

RE: Determine Centifugal Compressor Torque

Assuming this is a centrifugal machine, the theoretical torque demand is proportional to the square of the speed (rpm). However, theory doesn't apply from say 0 to 25% speed - there is a "stiction" effect to overcome - you need to get the rotor moving. The vendor torque-speed curve should look something like a tick mark.


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