×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Are you an
Engineering professional?
Join Eng-Tips Forums!
• Talk With Other Members
• Be Notified Of Responses
• Keyword Search
Favorite Forums
• Automated Signatures
• Best Of All, It's Free!

*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.

Motor turn down - what does it mean?

Motor turn down - what does it mean?

(OP)
In a new position at work, and guys around me are talking about motor "turn down".

Would someone please give me a description of what "turn down" means.

Thanks

Mark

RE: Motor turn down - what does it mean?

Sure someone else can explain this a bit better than I can but as far as I'm aware, turndown ratio is simply the ratio of the rated speed to the minimum speed at which the motor can handle the rated load.
Therefore a higher turndown ratio implies slower speeds are possible without causing damage.  i.e. the speed can be "turned-down" more.

RE: Motor turn down - what does it mean?

I've heard the term in relation to motors with variable speed capabilities, i.e., variable speed drives, and "turn down" is the minimum speed that the motor will be useful, such as able to spin up the load equipment.

Our motors have a range of 50-105% RPM.  At 50%, the centrifugal compressors are  spinning but at normal operating pressures they're performing very little compressing.

old field guy

RE: Motor turn down - what does it mean?

I have always known the phrase "turn down" to express the ratio of maximum over minimum in regards to a variable quantity.
Example; a gas burner will operate over a range of 250,000 BTU/Hr. to 10,000,000 BTU/Hr. The turn down ratio is 10,000,000/250,000 = 40 or 40:1
Does this explanation fit your context?

Bill
--------------------
"Why not the best?"
Jimmy Carter

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.

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

• Talk To Other Members
• Notification Of Responses To Questions
• Favorite Forums One Click Access
• Keyword Search Of All Posts, And More...

Register now while it's still free!