The current account of balance of payments includes both balance of trade accounts and the invisible account. It is thus the sum of visibles balance and invisibles balance on current account whereas the capital account of balance of payment indicates all the inflows and outflows of capital. Those flows of capital may be in the form of borrowings from and lending to abroad, both by the private and government etc.
Balance on Current account = Sum of credits on current account - sum of debits on current capital account
Whereas
Balance on capital account = Sum of credits on capital account - Sum of debits on capital account
Since, import of machinery is import of a good, so it is recorded in the current account, which deals with the import and export of goods and services.