Our fan oven has always had a bit of a vibration noise from new (7+years ago).  Whilst I’ve got the plinths off in the kitchen for something else, I finally thought I’d investigate.

A process of elimination points squarely at the fan assembly.  I can move the blades in and out by a few mm.  The same is true if I remove the blades and just move the motor shaft. So I suspect the motor is the cuprit.  I think it’s just the motor moving within it’s housing, so I don’t necessarily think that the motor housing is loose.

Am I right in thinking that the motor shaft shouldn’t move like this?  in which case I’ll take it apart and take a look, I suspect it’ll just need a new motor.

or new bearings / bushes….

I replaced the bushings in our extractor fan motor as it was getting noisier (20 years old).

[url=https://flic.kr/p/QSNZzg]Rebuilding extractor fan motor[/url]

I think you will find that a new motor will have the same play in it , that type of motor often has play in it.

There are some thrust washers between the armature and the inside of the end plates but that is about it.

I would look to see if you can balance the blade , likely will need a basic jig to do that.

I did wonder if that might be the case re: a new motor.

Thinking about it though, as the play is all along the shaft (axial?) then it might just be something else that’s causing the noise.   I’ll experiment with running the motor without the blades and see if that changes anything.

I’ve found, when investigating similar things, that the running of the motor just sets up a vibration, that in itself is acceptable, but the frequency of this effects another part of the assembly and that is actually what is causing the noise.

Being that Ovens, tumble dryers, washing machines etc are made from thin steel sheeting, self tapped together, makes this effect all the more.

You probably want to re-assemble the motor, run it, whilst putting the palm of your hand on various parts of the oven, and then be prepared to tweak panels as necessary.

Or, it it as simple as the mains power cable sitting loose and vibrating on something?