Can anyone suggest a test to see if the 230V single phase motor is OK? When my bow thruster didn't work, I dug around and found that the Roto phase was disconnected with the terminals T1-T3 going nowhere. The 3-phase motor works when connected to 3 phase power, but it is the starter or step-up motor which is out of the circuit. Is there some form of resistance test by which I can avoid putting power to the motor and risk damage to the circuit? Since this is an inherited problem I have no History to go on.