A detection method for three-phase power supply phase loss during motor operation and a motor phase loss protection system

Abstract

The invention provides a three-phase power supply default phase detection method and a motor default phase protection system used in motor operation, and can achieve the following effects of rapidly and reliably detecting default phases and phase sequences of the motor in a dynamic state and a static state, satisfying default phase detection protection of the motor in an electric apparatus in a dynamic state and a static state, and avoiding long-time abnormal operating state of the motor. The three-phase power supply default phase detection method comprises the following steps of N101, starting and enabling the motor to operate; N102, sampling and detecting three-phase voltages, and determining whether the three-phase voltages are equal to zero or not; N103, if any one phase voltage in the three-phase sampling voltages is equal to zero, determining a default phase power-on state; N104, if the three-phase sampling voltages are all not equal to zero, continuing to determine whether the difference values of any two of the three-phase sampling voltages is overhigh or not; N105, if not, performing phase sequence detection; and N106, if the difference value is overhigh, determining a power-on default phase state. By adoption of the three-phase power supply default phase detection method, the default phase operation of the motor can be detected in real time, thereby providing effective guarantee to reduction of the default phase operation of the motor.

Description

technical field [0001] The invention relates to the technical field of three-phase AC asynchronous motors, in particular to a method for detecting lack of phase of a three-phase power supply during motor operation and a protection system. Background technique [0002] The power supply of the three-phase AC asynchronous motor often has a phase loss phenomenon. Such faults are difficult to be found, causing the motor to be in a phase loss operation state for a long time and causing danger. At present, the phase loss protection device of the three-phase AC motor in the electric device at home and abroad can only be The lack of phase detection is performed when the motor is not running (static). Although this device has a protective effect on the motor to a certain extent, it is far from enough. In practice, more than 60% to 70% of the motor burnout accidents are caused by the lack of phase operation. In addition, some other occasions that use sensors such as current sensors to ...

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Problems solved by technology

[0002] The power supply of the three-phase AC asynchronous motor often has a phase loss phenomenon. Such faults are difficult to be found, causing the motor to be in a phase loss operation state for a long time and causing danger. At present, the phase loss protection device of the three-phase AC motor in the electric device at home and abroad can only be The lack of phase detection is performed when the motor is not running (static). Although this device has a protective effect on the motor to a certain extent, it is far from enough. In practice, more than 60% to 70% of the motor burnout accidents are caused by the lack of phase operation. In addition, some other occasions that use sensors such as current sensors to measure three-phase current, and relay protection devices such as air switches, relays, and AC contactors to detect and protect motor phase loss cannot be widely used because of their shortcomings such as high environmental requirements and large space occupation. application, and the production and maintenance costs of the relay protection device are high, the reliability is low, and the economic benefit is low. Therefore, a low-cost, almost no sensor, high reliability, small footprint, and widely used During the operation of the motor (dynamically), the real-time detection of power supply phase loss to protect the system device of the motor becomes the key to improving the service life of the motor and ensuring safe production

The phase sequence automatic detection function is another element to ensure the reliable and normal operation of the motor, otherwise the motor will run out of control, which will directly lead to equipment damage, and even serious personal injury

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