It sounds like she wants to play with it! Dougie is the same, he jumps at the hoover, jumps back, barks at it, and wants me to chase him with it, he is the same with the hairdryer, he just loves a carry on.
I have gone through quite a few hoovers since having dogs, but recently got a Henry, and it is really quiet - although, Dougie just thought it was a new pal for him, especially as it has a big smiley face!
You can either just put up with her trying to play, or gradually desensitise her to it.