model A4S46DB4D. I was working on an oven today at a school that had a failed convection blower motor. Three phase 480 volts, had an open winding. The motor is a Leesam. Im getting a new motor and just kind of thinking in my head if something single phased this motor to open it up or did it just die of natural causes. I couldnt find a schematic but was wondering if anyone has any experience in losing this motor. Does the door switch have the ability to fail open and kill the motor?