Gearbox Bearings Won't Spin

NDE? What is NDE?
The cage and rollers are not turning which could quickly wear the bearing housing. It has been said its normal when the gearbox is not loaded?
Who ever said it was an idiot.
Don't believe everything that 'is said' use your own judgement too...ok you may occaisionally be wrong.
By the way do you know that below 2mph, your undriven car wheels just slide along...they don't rotate?
Del

Your example is wrong since the car wheels are always loaded by the car weight!

NDE Non Destructive Examation

In this case I would guess: Non Drive End

Whoever has said is right.

The unloaded bearings does not spin properly. In fact in a lot of gearbox testings we have seen (vertical axis) the CRB (cylindrical roller bearing) does not spin properly and it is more like stick and slip.

This gives a false idea of what you assumed.

BTW: why wear beariing housing? there is an outer race too isn't it?

We had had lot of interaction with the bearing men- SKF, FAG (now INA), Timken, Torrington (now Timken) etc. And all of them were unequivocal- do not run the bearings for long without load. Reason is obvious.

In fact a lot of our customers insist on the gear box to be tested on no loead, and we are forced, but we have reduced the testing time to the minimum.

A lot of bearings are given pre-load exactly to avoid this problem. But it is not possible everywhere and especiallin in most of our cases where a bit of large endplay is maintained to compensate for the on load and temperature changes.

In fact if the system is perfect, the NDE bearing rotates at the center of the axis and then the inner race does not touch the rollers at all does it? And hence no transfer of the rolling motion to the rollers and then the roller does not rotate, till some thing - aspertion, vibration,shock etc makes the shaft to touch it.

Of course I am assuming the design like our, vertical, with a CRB+ TRB/SRB on DE side and CRB on NDE side. The TRB and the DE-CRB maintains the shaft axis, the CRB on load end are to guide the shaft on load.

(BTW- for un-bearings - CRB= Cylindrical Roller Bearing, SRB= Spherical Roller Bearing, TRB= Taper Roller bearing)