×
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

Transformer Cooling Type Designation

Transformer Cooling Type Designation

Transformer Cooling Type Designation

(OP)
Hello. I am looking for some help witht the description of Power Transformer cooling type designations.
I am looking at two transformers with similiar characteristics.  
The first is a 115 KVA 3 phase transformer with the following MVA and cooling designations:
15/20/25 MVA (oil filled with cooling radiators/fins)
ONAN/ONAF/ONAF
Now I believe that these designations are as follows:
ONAN - oil natural, air natural; indicating that both the air and oil are allowed to flow and release heat through natural convection.
ONAF - oil natural, air forced (with fans running); forced air flow over the cooling fins and radiators.

The second transformer has the following rating 115 kVAC, 3 ph:
15/20/25 MVA (oil filled with cooling radiators/fins)
ONS/ONP/ONPP
ONS -?
ONP -?
ONPP -?
I think that these are similar designation but I am not completely sure (or even the French designation?).  Could somone either explan these designations or point me to a good information source?
Thanks,

RE: Transformer Cooling Type Designation

On your first transformer, Did you mean the last of the options being OFAF (Forced oil and forced air)i.e. both oil and air are moved by force. Oil is pump circulated.

I don't know about the markings on your second transformer, but they should mean the same I guess.

RE: Transformer Cooling Type Designation


IEEE Std C57.12.00-2000 Liquid-Immersed Distribution, Power and Regulating Transformers §5.1 ‘Cooling classes of transformers’ [noted as consistent with IEC 60076-2: 1993] does not list a “P” desgnation .
  

RE: Transformer Cooling Type Designation

fwiw, Google search for "ONS/ONP" gives a bunch of transformer hits. Still don't know what it means.

=====================================
Eng-tips forums: The best place on the web for engineering discussions.

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