Just like any other device, the electric motor also defective. Some of these electric motor problems can be fixed, while others no good fix, because the price will be high and it will be better to purchase a new electric motor.
There are also situations that the defect is not or the electric motor, as the problem may be caused by an electrical command or the starting capacitor.
When the electric motor does not turn, indicated is to use a multimeter to check whether the electric motor power supply is operating correctly.
When the electric motor does not rotate and only make fun, using a multimeter you will need to check whether the three-phase electric motor is with its burned capacitor or the incoming voltage is lower than the electric motor terminal voltage.
If the electric motor is three-phase, with the multimeter should be noted that it is not missing one phase if the circuit is using fuse and if the problem is burning, the fuse must be replaced, but in addition, it is important to understand, because the fuse has blown.