Yes, each workspace is limited to 20 Sculptor conversations per week.
A conversation starts when you initiate a chat from the homepage, use "Chat with Sculptor" in a table, or click the "+" button for a new chat. The entire chat thread counts as one conversation, not individual messages.
If you need any more help with Sculptor or have other questions, feel free to ask. Would you like to share more about what you're trying to accomplish with Sculptor?