【正文】 。這種方法的一個缺點 是，在操作的第一步電機(jī)發(fā)熱是大于通常遇到的跨行開始。一個特殊的起動器被配置為全電壓可用于纏繞的一半，然后在短暫的延遲后，到下半年。最常見的方法被稱為半繞組的方法。第二類有不同方式的運動身體可以改變處理啟動問題。他們將開始提供短路電壓關(guān)閉后過渡期。這提供了一個封閉的過渡，消除了由于切換瞬變的關(guān)系。由于浪涌電流減少，那么 T＞ E 壓降電阻銀行允許轉(zhuǎn)矩由電動機(jī)產(chǎn)生的增加。當(dāng)電機(jī)達(dá)到的速度，它開發(fā)了一個反電動勢（電磁場）反 對電機(jī)電壓。 When the motor is started, the resistor bank limits the flow of inrush current and provides for a voltage drop at the motor terminals. The resistors can be selected to provide voltage reductions up to 50%. As the motor es up to speed, it develops a counter EMF (electromagic field) that opposes the voltage applied to the motor. This further limits the inrush currents. As the inrush current diminishes, so does te voltage drop across the resistor bank allowing the torque generated by the motor to increase. At a predetermined time a device will short across the resistors and open the starting contactor effectively removing the resistor bank from the circuit. This provides for a closed transition and eliminates the concerns due to switching transients. 當(dāng)電動機(jī)啟動時，電阻銀行限制浪涌電流的流動，并提供電機(jī)端子的電壓降。 D. Primary Resistor or Reactor Starting 初級電阻或電抗起動 This method uses either a series resistor or reactor bank to be placed in the circuit with the motor. Resistor starting is more frequently used for smaller motors. 該方法利用一系列電阻器或電抗器的銀行被放置在電路與電機(jī)。如果驅(qū)動器是用于啟動電機(jī)，這些特征可能是不必要的。從驅(qū)動一個未經(jīng)過濾的輸出 信號可以在電機(jī)產(chǎn)生諧波電壓尖峰，強(qiáng)調(diào)電機(jī)繞組絕緣。如果沒有這些功能，軸電流，循環(huán)通過軸的軸承，通過電機(jī)支架與背，創(chuàng)造，導(dǎo)致軸承過早失效的軸承弧，潛在的電弧時需要考慮應(yīng)用電機(jī) /驅(qū)動封裝在一個危險的環(huán)境中，第二冊 /區(qū) ?；隍?qū)動器的輸出信號，過濾或未經(jīng)過濾的，可能需要額外的電機(jī)結(jié)構(gòu)特點。 The greatest drawback of the AFD is in the cost relative to the other methods. Drives are the most costly to employ and may also require specific motor designs to be used. Based on the output signal of the drive, filtered or unfiltered, the motor could require additional construction features. These construction features include insulated bearings, shaft grounding brushes, and insulated couplings due to potential shaft current from mon mode voltage. Without these features, shaft currents, which circulate through the shaft to the bearing, through the motor frame and back, create arcing in the bearings that lead to premature bearing failure, this potential for arcing needs to be considered when applying a motor/drive package in a hazardous environment, Division2/Zone2. 漁農(nóng)處的最大的缺點是成本相對于其他方法。電機(jī)仍應(yīng)尺寸大于所需的功率來驅(qū)動 負(fù)載。這允許啟動所需的負(fù)載功率的顯著減少，并降低了電機(jī)產(chǎn)生的熱量，所有這些總計達(dá)更高的效率。這使電機(jī)產(chǎn)生滿負(fù)載轉(zhuǎn)矩在整個調(diào)速范圍大，可達(dá) 10:1。它也是最昂貴的。根據(jù)驅(qū)動設(shè)備，這可能會導(dǎo)致令人興奮的系統(tǒng)的自然頻率。在以相同的預(yù)防措施，啟動轉(zhuǎn)矩應(yīng)遵循的軟起動器與其他降壓起動方法。 Tachometers can be used with solid state starters to control acceleration time. Voltage output is adjusted as required by the starter controller to provide a constant rate of acceleration. The same precautions in regards to starting torque should be followed for the soft starters as with the other reduced voltage starting methods. Another problem due to the firing angle of the SCR is that the motor could experience harmonic oscillating torques. Depending on the driven equipment, this could lead to exciting the natural frequency of the system. 轉(zhuǎn)速表能與固態(tài)起動器用于控制加速時間。電流限制為 175%到 500%的滿負(fù)荷電流編程的裝置。通過控制觸發(fā)角的晶閘管電壓，該裝置產(chǎn)生可控制的電動機(jī)起動過程中通過限制只有正弦波的時間部分功率流。 Additionally, the acceleration time should be evaluated to make sure that the motor has sufficient thermal capacity to handle the heat generated due to the longer acceleration time. 此外，加速時間應(yīng)進(jìn)行評估，以確保電機(jī)由于較長的加速時間產(chǎn)生足夠的熱容量的熱處理。用于驅(qū)動設(shè)備，隨著慣性力矩速度曲線可以用來驗證電機(jī)設(shè)計。在啟動過程中的另一個好處與自耦變壓器起動在盡可能低的振動和噪音水平。這個潛在的問題可以通過使用閉路過渡消除。在開放電路電壓的連接方法是作為它是從低電壓變?yōu)樗骄€。這種情況可能是一個預(yù)先設(shè)定的時間，目前的水平，總線伏，或電機(jī)速度。在 50%上的電壓電流是 25%次全電壓鎖定轉(zhuǎn)子電流。 A. Autotransformer 答：自耦變壓器 The motor leads are connected to the lower voltage side of the transformer. The most mon taps that are used are 80%, 65%, and 50%. At 50% voltage the current on the primary is 25% of the full voltage locked rotor amps. The motor is started with this reduced voltage, and then after a preset condition is reached the connection is switched to line voltage. This condition could be a preset time, current level, bus volts, or motor speed. The change over