[TowerTalk] Frozen Rotor

[David J Rodman MD]

Martin, if I read your post correctly, you did not mention about 
ice/snow or precipitation problems.  All you mention is cold and the 
rotor works in slightly warmer temps.  Maybe it is a stretch to think 
water is frozen someplace and EXTERNALLY freezing your rotor mast?  I 
would first think of an INTERNAL problem in the rotor like the rotor 
itself is freezing and the bearing grease has reached its low end of 
flowability or there is a wiring problem where a contact is just 
shrinking with the cold and then expanding later (less likely).  
Obviously, you could wait for a warmer day and then reshoot the thrust 
bearing too.  I would tend to think that eventually condensation will 
contaminate a bearing with water regardless of any protective covering 
applied.  Did you read the manual on the rotor or check the manufacturer 
temperature specifications yet?  Maybe the low end of the service temp 
is being exceeded?  Good luck.