A power converter converts power from a power source into power to be supplied to a motor having n-phase (n is an integer of 3 or larger) windings. The power converter includes an inverter including switches connected to the windings, a controller to control operation of each of the switches, and a failure detector to detect a sign of failure in a drive system ranging from the power source to the motor. When a sign of failure is detected by the failure detector, the controller is configured or programmed to check presence or absence of a failure in the drive system while supplying power to the motor by causing the inverter to perform a failure operation.