I'm trying to remove an exhaust fan from the 1950s which is connected to some conduit. I'm used to having a box that things are connected to so I have never removed a direct conduit connection. I have tried to turn the nut on the top with a wrench but to no avail. Not sure if there is a different way or I just need more strength.Photo from inside the fan housing 
And photo from above where the conduit is connected