Here's how you can exclude certain folders from your Time Machine backups.
1. Go to System Preferences.
2. Go to Time Machine.
3. Go to Options.
4. Click the + sign to add the folders you want to exclude from your backups.
5. You can also drag and drop folders into the exclusion window.
6. Click the Save button when you are finished adding folders.
For more, see the original article at the link below.
Exclude Folders from Time Machine Backups | OS X Daily