Hello!
VARDANA's colleague is right. Thanks for sharing your opinion. Well, after 20 years I returned to the country and started to do something. Some minor repairs, where of course I recommended proven bearings, usually SKF, and what? Disappointment...
I first replaced the bearings in the GORENJE washing machine, the weak ones were Slovenian (but they got water from a faulty sealant), so I can't judge, because in this situation any bearing would have died. The washing machine is now 24 years old and despite minor corrosion spots on the housing - it works great. Next it fell to the eco-pea cooker. While the worm gearbox, slow speed, got new SKF and new oil like honey, it was no longer so good with the fan. I suspect that the gearbox in "honey" oil from the Jedlicze refinery would have survived even on bearings from China. The fan, after replacement with SKF, behaves as if they were dry, chirps and makes high-pitched noises, as if there were dry clearances. Ok - I thought maybe I had banged the hammer too hard, although I was really gentle. And so 2 years went by and nothing changed. Then there was the timing gear with pump on the 1.6HDI engine, where the mechanic when he heard SKF said he wouldn't be taking it apart in a month! It wasn't until I overhauled a ZIEHL-ABEGG fan, where a 3 kW PM motor, with integrated inverter, drives the fan up to 4000 rpm, where there were Chinese bearings and after 2 years the fan play was 3 cm - it was rubbing against the housing and the bearings had carved the mounting hole sideways and axially - that I became convinced of the quality of the bearings in those days. A lathe-miller friend made a reinforcement, in the form of steel rings on the outside and inside of the alu-housing and we seated without "run-out" 2 x 6003 ZZ SKF. After starting the fan, I was afraid to approach because there was such a strange noise, as if it was going to come apart. To me it looks like the bearings are dry.... By now it's been 2 weeks and I've set the air handling unit to a safe speed and we'll see. I am disappointed that after such overhauls it can be even worse than before! When I used native F£Ts, there were never any disappointments, only after a long time one complained that they had died - and now? We mount the fallen ones.....
Greetings !