Abstract: A method for checking an out-of-step of a synchronous motor includes detecting electric degrees of the synchronous motor, in which the electric degrees comprise at least a first electric degree and a second electric degree detected at a preset interval, and the second electric degree is detected after the first electric degree; comparing the first electric degree with the second electric degree to obtain a comparing result; and determining that the synchronous motor is out of step when the comparing result satisfies a preset requirement. It is determined that the synchronous motor is out of step when the electric degree keeps unchanged or decreases progressively, or an increment of the electric degree is very small.

Abstract: A method for checking an out-of-step of a synchronous motor includes detecting three-phase currents of the synchronous motor; determining whether a relationship between the three-phase currents satisfies a preset requirement; and if no, determining that the synchronous motor is out of step. It is determined that the synchronous motor is out of step when amplitudes of each current of the three-phase currents are not equal or when the phase difference between the three-phase currents is not 120°.

Abstract: A method for checking an out-of-step of a synchronous motor includes detecting three-phase currents of the synchronous motor; determining whether a relationship between the three-phase currents satisfies a preset requirement; and if no, determining that the synchronous motor is out of step. It is determined that the synchronous motor is out of step when amplitudes of each current of the three-phase currents are not equal or when the phase difference between the three-phase currents is not 120°.

Abstract: A method for checking an out-of-step of a synchronous motor includes detecting electric degrees of the synchronous motor, in which the electric degrees comprise at least a first electric degree and a second electric degree detected at a preset interval, and the second electric degree is detected after the first electric degree; comparing the first electric degree with the second electric degree to obtain a comparing result; and determining that the synchronous motor is out of step when the comparing result satisfies a preset requirement. It is determined that the synchronous motor is out of step when the electric degree keeps unchanged or decreases progressively, or an increment of the electric degree is very small.

Abstract: An open phase detection system and method for a three-phase motor is provided. The open phase detection system comprises: a signal generating unit coupled to the three-phase motor and configured to generate a driving signal for driving the three-phase motor; a detecting unit coupled to the signal generating unit, and configured to detect whether the signal generating unit generates the driving signal and to detect three-phase current values of the three-phase motor; and a determining unit coupled to the detecting unit, and configured to determine whether the three-phase motor has open phase according to the three phase current values detected by the detecting unit when the driving signal is detected.

Abstract: An open phase detection system and method for a three-phase motor is provided. The open phase detection system comprises: a signal generating unit coupled to the three-phase motor and configured to generate a driving signal for driving the three-phase motor; a detecting unit coupled to the signal generating unit, and configured to detect whether the signal generating unit generates the driving signal and to detect three-phase current values of the three-phase motor; and a determining unit coupled to the detecting unit, and configured to determine whether the three-phase motor has open phase according to the three phase current values detected by the detecting unit when the driving signal is detected.