Regex to match more than 2 white spaces but not new line

Put the white space chars you want to match inside a character class. For example:

[ \t]{2,}

matches 2 or more spaces or tabs.

You could also do:

[^\S\r\n]{2,}

which matches any white-space char except \r and \n at least twice (note that the capital S in \S is short for [^\s]).