The most common and most likely answer to this crossword clue is the 7 letter word WHIRRED
I've seen this crossword clue in The Daily Telegraph
W
H
I
R
R
E
D
More clues leading to the result WHIRRED
Buddy explains!

The straight part
We know that "went round fast" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case went round fast = whirred.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does WHIRRED mean?
WHIRRED verb- To move or vibrate (something) with a buzzing sound.
- To make a sibilant buzzing or droning sound.
- To cause (something) to make such a sound.