Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_1847180_3 (state__class_ VARCHAR, date_of_successors_formal_installation VARCHAR)

### Question ###
What was the state (class) where the new successor was formally installed on May 11, 1966?

### Accurate SQL ###

SELECT state__class_ FROM table_1847180_3 WHERE date_of_successors_formal_installation = "May 11, 1966"