My old motor would make bearing noise after 5 min of operation, bearings went bad. I replaced the motor and capacitor today. Wiring was identical common white Black wire hi speed red wire low speed and white common. The yellow and blue are not used nor there they used on the old motor. Made up the connections and the motor will only hum / buzz. I tried the old capacitor and nothing changed.My next step is the contactor. The old motor did start up so I do not see how the contactor could be the culprit

Does the fan turn freely when turned by hand? It's easy to get the fan incorrectly positioned on the shaft.