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


temp limits for new generator

temp limits for new generator

temp limits for new generator

Dear all;

If you had to purchase a new generator, - 400 MW, H2 inner cooled - what is the maximum temperature that you would expect to measure at full load? For the windings, assuming class F, in theory you could accept 155 ºC - 15 ºC for hot spot tolerance = 140 ºC... but I have never seen any generator running hotter than 90 ºC as measured by RTD. On the other hand, what would be a safe level of temperature to have in the core, especially in the end of the core, when absorbing reactive power? Are you aware of standards that give values for this? Any ideas will be appreciated.

RE: temp limits for new generator

Many designs are insulated for Class F service but designed to run at the Class B limits to ensure long life of the insulation. With Class H and Class 220 materials available it is possible to run at the Class F limits with a similar margin to extend the life of the insulation system. This tends to be a requirement in a client specification rather than something defined in a standard.

RE: temp limits for new generator

Operating class F machines at 140 deg C will invariably lead to less life cycle. As Scotty says, class B limit of 120 deg C winding temperature max is the best way to go despite OEM claims of higher temperature limits.

As for the end core heating during mainly VAR loads, it is more the winding temperature that comes into play (due to its temperature limits) than the core temperature itself, which can sustain higher temps.


RE: temp limits for new generator

Thanks Scotty and Muthu. Yes, you are right, Class F insulation running at Class B temperatures has been a common requirement for other generators we have purchased.
Kind regards

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!


White Paper: Rapid Manufacturing with FDM
The automotive industry is increasingly turning to additive manufacturing, and fused deposition modeling (FDM) specifically, as a reliable alternative to traditional metal-cutting methods, like milling, turning and boring. Download Now
White Paper: Revolution in Design
Open up new possibilities for your business by changing the way you think about product development. Compared to traditional methods, 3D printing offers advantages that allow you to make more innovative products and get them to market faster. Download Now

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:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close