Tony M Nov 11, 2011:

Hydrogen cooling I was as surprised as you, Johannes, but in the context of a recent translation project, I had occasion to research this quite thoroughly, and highly inflammable hydrogen is indeed used for cooling purposes in generators!

I think it avoids some of the potential corrosion problems, but there must be other good reasons. Of course, it is only for these HUGE generators!

I was equally surprised when I learnt some 40 years ago that STEAM is used for cooling in high-power TV transmitters!! Hard to imagine, isn't it?

Johannes Gleim Nov 11, 2011:

Problem: I know how electricity is generated, no problem with that. Normally we have either no cooling, air cooling (by fan) and/or water cooling through tubes inside the stator. Hydrogen is too dangerous for being used in generators (inflammable and explosive) at ambient temperatures. But it may be used for cooling down to to zero point of the absolute temperature scale (to some °K), where metals and metal alloys loose their resistance and change to superconductivity. This looks being probable as googling for "hydrogen field cooling" shows corresponding results.

Proelec Nov 11, 2011:

@ Johannes C'est ici, d'après ce que j'ai compris, une exécution spéciale.
Le "champ" dont il est question, c'est en fait l'excitation.

D'une part, le paquet de tôles (fixe dans le stator) abrite un enroulement d'excitation ET les enroulements statoriques. C'est ce paquet qui est refroidi par circulation d'hydrogène.

D'autre part, en quelque sorte en supplément/complément, les "barres statoriques" sont munies d'un refroidissement par eau.

Tony M Nov 11, 2011:

@ Johannes Normally, it's the stator that produces the electricity output, and the rotor that generates the rotating 'field'; that's why there are two different cooling methods used, one for the stator and one for the rotor.

Johannes Gleim Nov 11, 2011:

Est-ce que vous avez plus de contexte sur la fonction de ce générateur ?
Je m'étonne qu'il ait deux moyens de refroidissement, une pour le champ et l'autre pour la bobine du stator. Je ne peux pas croire que serait un champ magnétique, impossible de "refroidir". Est-ce que ce la bobine du rotor qui génère le champ ?

Les liens http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=4821... laisse penser à la supraconductivité. Est-ce que c'est le cas ici ?