Over the years I have installed an attic fan in my house and in my garage. They do make a difference. I have replaced three of these motors since 1985. They probably were good but I didn't know it. These motors are open shaded pole 42 frame motors. They have an oiler wick in the front and rear. There are no bearings. Because of the heat in your attic, the wicks dry. They need to be oiled regularly. Who wants to climb into the attic with 110 degrees in the summer heat and oil your fan motor? Then again, don't they always fail in the summer? These motors, I discovered, don't burn out, they seize on the shaft due to lack of oil, the overload protector overheats, then it turns itself off. But alas, these motors can be fixed. Here's how: