How many times can your edits on another persons question be rejected before it's disabled? How long is the penalty?
When deciding on whether we should ban or not, we now look at your last 7 days of activity.
(rejects - (approvals / 3)) >= 5, you will be auto-banned.
This thread puts the penalty at seven days of edit banning.
Both posts are fairly old, though this newer thread confirms them. The exact details might have changed slightly. This is not to say that you should go and experimentally figure out where the boundaries currently sit.
For more, see the edit-ban tag on Meta Stack Exchange.