任何一款電器產(chǎn)品，當(dāng)然包括電機(jī)產(chǎn)品，都對(duì)其正常運(yùn)行的額定電壓進(jìn)行了規(guī)定，任何的電壓偏離均會(huì)對(duì)電器的正常運(yùn)行造成不良后果。

對(duì)于相對(duì)較高端的設(shè)備，采用了必要的保護(hù)裝置，當(dāng)電源電壓出現(xiàn)異常時(shí)，采用切斷電源的方式進(jìn)行了保護(hù)，對(duì)于非常精密的儀器，則采用恒壓電源進(jìn)行調(diào)整，而電機(jī)產(chǎn)品，特別是工業(yè)用電機(jī)產(chǎn)品，采用恒壓裝置的可能性極小，斷電保護(hù)的情況更多一些。

對(duì)于單相電機(jī)，只存在電壓高與低兩種情況，而對(duì)于三相電機(jī)還存在電壓的平衡問(wèn)題，這三種電壓偏離對(duì)影響的直接表現(xiàn)為電流增大或電流不平衡。

電機(jī)的技術(shù)條件中規(guī)定，電機(jī)的額定電壓上下偏差不能超過(guò)10%，電機(jī)的轉(zhuǎn)矩與電機(jī)端電壓的平方成正比，當(dāng)電壓過(guò)高時(shí)，電機(jī)鐵芯將處于磁飽和狀態(tài)，定子電流的增大將導(dǎo)致繞組嚴(yán)重發(fā)熱，甚至出現(xiàn)繞組燒毀的質(zhì)量問(wèn)題；而對(duì)于電壓偏低的情況，一種是電機(jī)的啟動(dòng)可能會(huì)存在問(wèn)題，特別是對(duì)于帶載運(yùn)行的電機(jī)，為了滿(mǎn)足電機(jī)的帶載運(yùn)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(zhǎng)期的低壓運(yùn)行，該問(wèn)題更為嚴(yán)重。

三相電機(jī)電壓不平衡，是典型的供電電源問(wèn)題，當(dāng)電壓不平衡時(shí)，勢(shì)必會(huì)導(dǎo)致電機(jī)電流的不平衡問(wèn)題。不平衡電壓的負(fù)序分量在電機(jī)氣隙中產(chǎn)生一個(gè)與轉(zhuǎn)子轉(zhuǎn)向相反的磁場(chǎng)。電壓中很小的負(fù)序分量可能使得流過(guò)繞組的電流比電壓平衡時(shí)的電流大很多。流過(guò)轉(zhuǎn)子導(dǎo)條中的電流頻率幾乎是額定頻率的2倍，因此轉(zhuǎn)子導(dǎo)條中的電流擠流效應(yīng)使得轉(zhuǎn)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(yùn)行時(shí)的溫升增高。

當(dāng)電壓不平衡時(shí)，電動(dòng)機(jī)的堵轉(zhuǎn)轉(zhuǎn)矩、小轉(zhuǎn)矩以及大轉(zhuǎn)矩都將減小。若電壓不平衡很?chē)?yán)重，則電動(dòng)機(jī)將不能正常工作。

當(dāng)電動(dòng)機(jī)在不平衡電壓下滿(mǎn)載運(yùn)行時(shí)，由于轉(zhuǎn)差率隨著轉(zhuǎn)子附加損耗的增加而增大，因而此時(shí)轉(zhuǎn)速會(huì)略微下降。隨同電壓（電流）不平衡程度的增大，電動(dòng)機(jī)的噪聲和振動(dòng)可能增強(qiáng)。振動(dòng)可能損害電動(dòng)機(jī)或整個(gè)驅(qū)動(dòng)系統(tǒng)。

為了有效甄別電機(jī)電壓不平的原因，可能通過(guò)電源電壓檢測(cè)或電流變化情況的方法進(jìn)行。大多數(shù)設(shè)備上都配有電壓監(jiān)控儀表，可以通過(guò)數(shù)據(jù)對(duì)比進(jìn)行分析，而對(duì)于沒(méi)有監(jiān)控裝置的情況，則應(yīng)采用定期檢測(cè)或測(cè)定電流的方式進(jìn)行；對(duì)于可以正反轉(zhuǎn)的電機(jī)，在不影響被拖動(dòng)設(shè)備的情況下，可以任意調(diào)換兩相供電線(xiàn)，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(wèn)題后，可能就會(huì)涉及匝間、相間等質(zhì)量問(wèn)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.