任何一款電器產品，當然包括電機產品，都對其正常運行的額定電壓進行了規(guī)定，任何的電壓偏離均會對電器的正常運行造成不良后果。

對于相對較高端的設備，采用了必要的保護裝置，當電源電壓出現異常時，采用切斷電源的方式進行了保護，對于非常精密的儀器，則采用恒壓電源進行調整，而電機產品，特別是工業(yè)用電機產品，采用恒壓裝置的可能性極小，斷電保護的情況更多一些。

對于單相電機，只存在電壓高與低兩種情況，而對于三相電機還存在電壓的平衡問題，這三種電壓偏離對影響的直接表現為電流增大或電流不平衡。

電機的技術條件中規(guī)定，電機的額定電壓上下偏差不能超過10%，電機的轉矩與電機端電壓的平方成正比，當電壓過高時，電機鐵芯將處于磁飽和狀態(tài)，定子電流的增大將導致繞組嚴重發(fā)熱，甚至出現繞組燒毀的質量問題；而對于電壓偏低的情況，一種是電機的啟動可能會存在問題，特別是對于帶載運行的電機，為了滿足電機的帶載運行，電流也必須要增加，電流增加的后果同樣是繞組的發(fā)熱乃至燒毀，特別是長期的低壓運行，該問題更為嚴重。

三相電機電壓不平衡，是典型的供電電源問題，當電壓不平衡時，勢必會導致電機電流的不平衡問題。不平衡電壓的負序分量在電機氣隙中產生一個與轉子轉向相反的磁場。電壓中很小的負序分量可能使得流過繞組的電流比電壓平衡時的電流大很多。流過轉子導條中的電流頻率幾乎是額定頻率的2倍，因此轉子導條中的電流擠流效應使得轉子繞組的損耗增加值比定子繞組損耗增加值大很多。定子繞組溫升比在平衡電壓下運行時的溫升增高。

當電壓不平衡時，電動機的堵轉轉矩、小轉矩以及大轉矩都將減小。若電壓不平衡很嚴重，則電動機將不能正常工作。

當電動機在不平衡電壓下滿載運行時，由于轉差率隨著轉子附加損耗的增加而增大，因而此時轉速會略微下降。隨同電壓（電流）不平衡程度的增大，電動機的噪聲和振動可能增強。振動可能損害電動機或整個驅動系統(tǒng)。

為了有效甄別電機電壓不平的原因，可能通過電源電壓檢測或電流變化情況的方法進行。大多數設備上都配有電壓監(jiān)控儀表，可以通過數據對比進行分析，而對于沒有監(jiān)控裝置的情況，則應采用定期檢測或測定電流的方式進行；對于可以正反轉的電機，在不影響被拖動設備的情況下，可以任意調換兩相供電線，觀察電流變化情況，而間接分析電壓的平衡情況，在排除電壓不平的問題后，可能就會涉及匝間、相間等質量問題。

Any electrical product, including motor products, has specified the rated voltage for its normal operation, and any voltage deviation will cause adverse consequences to the normal operation of the electrical appliance.
For relatively high-end equipment, necessary protective devices are used. When the power supply voltage is abnormal, the power supply is cut off for protection. For very precise instruments, constant voltage power supply is used for adjustment. However, for motor products, especially industrial motor products, the possibility of using constant voltage devices is very small, and there are more situations of power outage protection.
For single-phase motors, there are only two types of voltage: high and low, while for three-phase motors, there is also a voltage balance problem. The direct impact of these three voltage deviations is an increase in current or an imbalance in current.
According to the technical specifications of the motor, the deviation between the rated voltage of the motor cannot exceed 10%, and the torque of the motor is proportional to the square of the motor terminal voltage. When the voltage is too high, the motor core will be in a magnetic saturation state, and an increase in stator current will cause serious heating of the winding, even leading to quality problems such as winding burnout; For situations where the voltage is low, one possibility is that there may be problems with the starting of the motor, especially for motors operating under load. In order to meet the load operation of the motor, the current must also increase. The consequence of the current increase is also the heating or even burning of the winding, especially for long-term low-voltage operation, which is even more serious.
The voltage imbalance of three-phase motors is a typical power supply problem. When the voltage is unbalanced, it will inevitably lead to the imbalance of motor current. The negative sequence component of unbalanced voltage generates a magnetic field in the motor air gap that is opposite to the rotation of the rotor. The small negative sequence component in the voltage may cause the current flowing through the winding to be much larger than the current at voltage balance. The frequency of the current flowing through the rotor conductor is almost twice the rated frequency, so the current squeezing effect in the rotor conductor causes the increase in losses of the rotor winding to be much greater than that of the stator winding. The temperature rise of the stator winding is higher than that when operating under balanced voltage.
When the voltage is unbalanced, the locked rotor torque, small torque, and large torque of the motor will all decrease. If the voltage imbalance is severe, the motor will not function properly.
When the motor operates at full load under unbalanced voltage, the speed will slightly decrease due to the increase in slip rate as the additional loss of the rotor increases. As the degree of voltage (current) imbalance increases, the noise and vibration of the motor may increase. Vibration may damage the electric motor or the entire drive system.
To effectively identify the cause of uneven motor voltage, methods such as power supply voltage detection or current changes may be used. Most devices are equipped with voltage monitoring instruments, which can be analyzed through data comparison. However, for situations without monitoring devices, regular testing or current measurement should be used; For motors that can rotate in both directions, without affecting the dragged equipment, the two-phase power supply lines can be freely swapped to observe the current changes, and indirectly analyze the voltage balance. After eliminating the problem of uneven voltage, quality issues such as turn to turn and phase to phase may be involved.