Can you figure out the combination to this lock?

• There are three numbers in the combination
• The numbers on the dial range from 1 to 60
• The first number is twice the second number
• The second number is equal to one and a half dozen
• All the numbers in the combination are different
• The third number is greater than 50
• All the numbers sum to the same number

                                     __ __    -    __ __    -    __ __
                                                                          first number                 second number             third number