AVK generator loose the magnetic wedges 1

[181273]

first all, hello, I´m Jose M, live in Spain and work for the spanish generator and motor manufaturer Indar, and I work in the technical service.. after this, I ask my question,
I got an AVK generator and it loose the magnetic wedges, and now I think we need to replace it... but I don´t had any experience onto it... had you ever done it???
If I don´t use magnetic wedge, what is the real diference? someone of you had experience it???

 

[edison123]

Jose

If the wedges are loose, you can tighten by packing them underneath. If they are lost (I have seen lost wedges and never could figure out where they went), you need to rewedge.

If you do not use magnetic, the rotor pole faces will be overheated and damage the rotor winding. I have learnt this a huge personal cost.

If the stator winding is global VPI (which is normal with AVK), you should be careful how you rewedge without damaging the stator winding.

 

[edison123]

correction

If you do not use magnetic wedges, the rotor pole faces will be overheated and damage the rotor winding. I have learnt this at a huge personal cost.

 

[181273]

now i´m rewedgering them, and not all of them are out, but maybe a 25 % of them are out, and yes, It´s VPI, this is why I scared about it, cause of the imposibility of avoid the presence of air between the wedge and the winding....
Does somebody knows how much the poles faces will heat? maybe 20º C??

thanks in advance,

 

[edison123]

Jose

I wouldn't worry about air gap below the wedges since it is not partial discharge area.

However, I would be very careful when rewedging (not put too much pressure when driving the wedge) so as not to damage the winding.

Without magnetic wedges, the pole faces would heat enough to destroy the rotor winding.

I never have liked partial repair works since the client, who wants to save the time & money, will never reconcile himself to the risks that come with partial repair works. Now, I point out the risks involved and if he still insists on part work, I refuse to do the job. Better to lose the money than the name.

 

[edison123]

Jose

If your last name is Fuente, you might want to check your e-mail to me 4th april and my reply on 5th april 2006.

 

[181273]

no, this guy is Josetxo de la fuente, my name is Jose M. Cruz Meira, and yes, he´s the guy that deals with cogeneration thing....
thanks for your answers, now I rewedge them, and against my opinion, but at least money is money...

what is your relation with Jose de la Fuente?? We had sometime some dissapointments...

Another question about the rewedgering work is that I want to use epoxy under the wedge to fix it more, what kind of epoxy will you use, it seems you got experience with it.

Other question, I use the wedges we use normally on factory to wedgering the stators, but ... I don´t know if there´s different kind of materials for wedges??

thank in advance

 

[edison123]

Using epoxy below the wedges will make it harder to remove them in future.

For AVK generators, you need magnetic wedges, which are special wedges with iron fillings with specific magnetic properties. Using your normal insulating wedges will not work.

As for other things, pls contact this forum help (use the "contact us" icon in the upper right top corner of this page) to get my e-mail id.