I have created a wf rule with time based action which will run after 1 hr rule triggered date and update checkbox send_Email__c to true.
In process builder i have added the criteria is if Owner_active__c(formula field on custom object)=true && sen_Email__C =true then in immidiate action sending an email alert.
made checkbox Recursion=true
here the problem is after wf is updating a field to true ,process builder is not calling and sending mail.