電機定子繞組的溫升與電流呈正相關(guān),電流增大時,溫升自然也會增加,而且增加的幅度還要大一些。除電流影響外,溫升還與其他關(guān)聯(lián)因素有關(guān),如生產(chǎn)加工過程中工藝波動、質(zhì)量控制等因素。為規(guī)避由于工藝波動等因素可能導(dǎo)致的不符合,產(chǎn)品設(shè)計時應(yīng)留有一定的裕度。
電機產(chǎn)品技術(shù)條件中會對電機額定電壓、頻率范圍進行了規(guī)定,超出該范圍時電動機將無法正常工作,因而應(yīng)保證電機所對應(yīng)的電網(wǎng)參數(shù)符合電機正常運行條件,直接是電壓對于電機繞組的影響,特別是在戶外架接的臨時線路,出于成本及物料安全性等原因,臨時線路更多的情況選擇鋁芯線,導(dǎo)致真正施加于電機的電壓嚴重不足,此時電機電流特別大,結(jié)果會導(dǎo)致電機嚴重發(fā)熱,在較短時間內(nèi)因過熱而燒毀。
當電機成品溫升不合格時,補救措施不多,我們可以通過增加浸漆次數(shù)、增大風扇寬度及外徑、車小轉(zhuǎn)子直徑以增大氣隙等犧牲其他性能的方式進行溫升控制和補救。加大氣隙,對2極電機可能有效,因為雜散損耗下降,轉(zhuǎn)子對定子的熱輻射減弱;但對多極電機可能得不償失,因為勵磁電流會增大明顯。

The temperature rise of the motor stator winding is positively correlated with the current. As the current increases, the temperature rise naturally also increases, and the increase is even greater. In addition to the influence of current, temperature rise is also related to other related factors, such as process fluctuations and quality control during production and processing. To avoid possible non conformities caused by process fluctuations and other factors, a certain margin should be left in product design.
The technical specifications for motor products specify the rated voltage and frequency range of the motor. If it exceeds this range, the motor will not be able to operate normally. Therefore, it is necessary to ensure that the corresponding power grid parameters of the motor meet the normal operating conditions of the motor. The most direct impact is on the voltage of the motor winding, especially for temporary lines connected outdoors. Due to cost and material safety reasons, aluminum core wire is more commonly used for temporary lines, This leads to a serious shortage of voltage applied to the motor, where the motor current is particularly high, ultimately resulting in severe heating of the motor and burning out due to overheating in a short period of time.
When the temperature rise of the finished motor is not up to standard, there are not many remedial measures. We can sacrifice other performance methods such as increasing the number of times the motor is immersed in paint, increasing the width and outer diameter of the fan, and increasing the diameter of the small rotor to increase the air gap for temperature control and remediation. Increasing the air gap may be effective for 2-pole motors, as stray losses decrease and the thermal radiation from the rotor to the stator weakens; But for multipole motors, the benefits may not outweigh the losses, as the excitation current will increase significantly.
