You can write trivar (info@trivar.com), but I'm fairly sure the black is the incoming line feed, the red goes to the motor, and the gray is the other leg of your incoming feed (neutral in this case likely).

You're going to have to also figure out what the wires coming into the box are connected to. You might get some hint if you open up the fan (sometimes you can just remove the bell-shaped cover without taking the fan down to see the wiring). Does the fan also have a light?

Thanks but I have the received the information from another source.