Oil from Exciter

K

Thread Starter

karim elrawy

We have oil leaks from the exciter and we drained it but we don't know what this problem is
 
karim elrawy,

Check the push-buttons; they require oil for smooth operation.

Or, it's possible that the brushes are leaking.

Seriously though, exciters on GE-design Frame 9# heavy duty gas turbines don't require oil. The oil is likely leaking out of the bearing housing/pedestal on the collector end of the generator and into the "exciter" as you call it, which is just the collector enclosure. (The "collector" of a synchronous generator is where the brushes and brush rigging and slip rings are located--presuming the generator is excited by a static excitation system connected to the rotating field through brushes and slip-rings. The slip-rings are the shiny rings on the generator shaft which the brushes ride on. One set of slip rings is for the negative side of the field; the other set of slip rings is for the positive side of the field.)

While I've never seen one on GE-design Frame 9E heavy duty gas turbine's generator there are "brushless" exciters which don't use brushes, but rather use induction to generate AC on a rotating exciter which is rectified through a diode bridge also located on the shaft which supplies the DC to the rotating field. The enclosure which houses the AC armature and the rotating diode wheel is still commonly referred to as the "collector compartment," though.

And, it's still most likely that the source of any oil in the collector compartment is coming from the generator bearing at that end of the generator (the non-drive end, or the non-turbine end--the collector end) of the generator.

Please write back to let us know what you find.
 
CSA, given I have not seen any new designs in a couple decades and never a CT you had me there!

The older exciters for LSTG did have problems where their bearings leaked in to the exciter frame. they were nearly always caused by improper assembly. I did have one problem where the exciter was in an outdoor enclosure and the customer added filtration such there was a very negative pressure (collector ring cooling fan) in and around the exciter and it draw oil mist out of the bearing pedestals.

Given the OP did not specify unit/vintage (and not being controls) I did not ask for specifics

Now, I'll keep look out for those pressurized oil push buttons!

>Check the push-buttons; they require oil for smooth operation.
>Or, it's possible that the brushes are leaking
 
JFB,

Yeah, sorry; I couldn't resist.

I think the exciters you're talking about are Alterrex and/or Generrex, right? They were actually rotating exciters of some sort (I've never actually seen either, most of my experience being with CTs of much smaller output than LSTGs).

Other than brushless exciters, I've never seen a rotating exciter on a GT, and I've never seen a brushless exciter on a GE-design Frame 9E heavy duty gas turbine. But, the Belfort Bunch are doing a lot of different things these days (because they can).

But, it's a good idea--oil-filled push-buttons on the collector enclosure. They could be programmable and used for just about anything!
 
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