Yes 3 in 1 oil would be good to use.
Attic fan motor oil.
You can make an electric fan last longer if you simply lubricate the motor on a regular basis.
An electric fan is no different.
They are in the very center where the fan shaft goes.
This lubricant oil is produced by liberty oil products and it is a 100 synthetic oil compound.
An attic fan doesn t require annual maintenance.
There is a bearing on each end of the motor.
Then slowly pour 1 2 ounces of oil into the oil hole.
It is excellent for smaller electric fan motors because it helps to reduce friction when there is a moving surface.
The bottom one is under the very center silver spot in your photo and the other is where the shaft enters the motor on the top side.
Doing small maintenance on your appliances can extend the life of them by years.
You should oil the motor bearings.
How to lubricate electric fan motors.