Time Format-Activeadmin

I'm using time data type in my model, I used open_time.strftime('%I:%M:%S:%p') to save the time, But I got a problem while retrieving the data from model using "Rest Client Api" it returns the time data as "open_time": "2000-01-01T05:02:00+05:30" instead of HH:MM:SS format. Need help!