Dear spectrometer admins,
many, many thanks. I got three really helpful responses from Markus Voehler,
Peter Kaden and Bert Heise.
Peter found a complete product guide including the explanation of this strange "2R5"
https://www.tande.com.tw/te-fan/2011Produc.pdf
The explanation is given at the third page of this catalogue and means
2 - 2 ball bearing
R - third wire delivers an alert signal (no tacho)
5 - speed
Bert told a little bit about his experience with fans, especially their lifetime.
This is essential, because the catalogue tells, that the FD121225MB fan is available
both with ball bearing and sleeve bearing. The difference is significant! The expected
lifetime for the ball bearing system is about 10 years and for the sleeve bearing only 3 years.
My reference fan doesn't reveal the kind of bearing (no 2R5 label ...).
Next monday I will try to figure out the kind of bearing with the help of specialists to
provide the final summary.
BTW: I didn't forget the final summary about the 1,2-Diphenylethane question. Everything
is finished, but because I believe, the underlying issue (magnetic nonequivalence in
conformationally unrestricted systems) is essential, I need more time to assemble everything
in a better quality compared to this summary.
Kind regards,
Rainer
Received on Sat May 29 2021 - 06:39:49 MST