10 mo suddenly crying at various noises - is this a temporary stage?

[bluesmile10]

10 mo DS used to be fine with the hoover, would sit in walker and watch washing machine etc. Suddenly he has started crying at those things, real frightened cry - even when the kettle goes on!!! Is it just a temporary stage? What should I do to help him become confident with them again?

Yes, this is normal and yes, it is temporary.
Both of my DCs went through stages of being terrified of the hoover. (Can't say they ever noticed the kettle though!)
It won't last long and you will soon find that he loves the hoover again and is fighting with you over who gets to use it.
In the meantime, just show him love and understanding and do your best to help him realise that these machines are neither dangerous nor scary.
It will pass soon enough.

Thank you RuthChan, makes me feel lots better about it