Contact US

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!

*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

Turboexpander Booster Compressor (TEBC) - Radial bearing temp sensor/element damaged

Turboexpander Booster Compressor (TEBC) - Radial bearing temp sensor/element damaged

Turboexpander Booster Compressor (TEBC) - Radial bearing temp sensor/element damaged

We have recently commissioned Booster Compressor driven by Turbo-expander with active magnetic bearings, everything went pretty fine during commissioning, however, after few days operation, unit was kept standby for more than three months. later, upon restart-up, unit experienced hard landing due to trip caused by mal-function of compressor radial bearing temperature (high high, set-point 130oC), in real the temperature was much lower, around 45oC. We found that main temperature element of radial bearing was faulty and sent trip signal to machine. Now it is established that temp elements (both main and spare) needs to be replaced. The replacement of temperature elements requires to dismantle complete plug-in unit of TEBC, since these elements are glued on magnetic lamination, meaning that complete machine has to undergo overhaul.

Just to share, the plug-in unit contains all rotating components including bearing cartridge, wheels etc of the turbo expander/compressor, expander and compressor wheels are mounted on a single rigid shaft, supported by 2 radial magnetic bearings and one axial magnetic bearing. TEBC speed 11500rpm.

Guys so what do u suggest whether it is safe to continue TEBC operation without radial bearing (compressor side) temperature monitoring!! since temperature elements PT100(both main and spare) of radial bearing are faulty and replace temp sensor later during machine's overhaul or otherwise. I will definitely opt the first one.


RE: Turboexpander Booster Compressor (TEBC) - Radial bearing temp sensor/element damaged

What I dont understand is why do you have a trip specified on journal bearing temperature when journal bearing purpose is for emergency landing in your case. I dont understand the design philosophy because if bearing temperature increases it means that the shaft has already landed and bearing started to operate but you are normally then shuting down the machine, so why having a trip then on these ? I am not specialist of magnetic bearing, so I might be missing something ?

For one of my project with centrifugal compressors, we dont trip on journal bearing temperature ; these are operating continuously and essential to machine operation (means we dont have magnetic bearings).

RE: Turboexpander Booster Compressor (TEBC) - Radial bearing temp sensor/element damaged


Machine has separate dedicated auxiliary (landing) anti-friction bearings, magnetic bearings holds machine while running,being levitated,therefore temperature of magnetic bearings is important parameter to be monitored/controlled. Besides just to share, machine has permanent gas cooling line to keep temperature of magnetic bearings within limit.


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! Already a Member? Login


Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. 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