直流電機(jī)原理-文庫(kù)吧資料
2025-08-11 10:12本頁(yè)面
【正文】 sformer (B) Start Contactor (A) Start Contactor Run Contactor 3 ~ M The Autotransformer Starter employs an autotransformer to reduce the voltage during the start period. The transformer has a range of output voltage taps that can be used to set the start voltage. 超動(dòng)期間 自耦變壓器起動(dòng)器使用自耦變壓器降低電壓。 Current can only be reduced to the point where torque output from the motor exceeds the torque required by the load. 電流只能降到電機(jī)扭矩輸出超過(guò)負(fù)載要求的扭矩的那個(gè)點(diǎn) Reduces start current. 降低起動(dòng)電流。 Motor Start Theory 14 0 50 100 150 200 250 300 100 90 80 70 60 50 40 30 20 10 0 SLIP (%) FULL LOAD TORQUE (%) 0 100 200 300 400 500 600 700 CURRENT (%) Full Voltage Starting Limitations 滿電壓起動(dòng)限制 1. Current transient 電流瞬變 1 2. Current magnitude 電流值 2 3. Torque transient 扭矩瞬變 3 4 4. Torque magnitude 扭矩值 Reduced voltage starting attempts to overe these limitations by applying the voltage gradually. 降壓起動(dòng)通過(guò)逐漸利用滿電壓的方式力圖克服這些限制。 Full Voltage Starting 滿 電壓起動(dòng) 0 50 100 150 200 250 300 100 90 80 70 60 50 40 30 20 10 0 SLIP (%) FULL LOAD TORQUE (%) 0 100 200 300 400 500 600 700 CURRENT (%) Motor Start Theory 13 Full Voltage Starting 滿電壓起動(dòng) 0 50 100 150 200 250 300 100 90 80 70 60 50 40 30 20 10 0 SLIP (%) FULL LOAD TORQUE (%) 0 100 200 300 400 500 600 700 CURRENT (%) Torque rises instantaneously to LRT levels. This causes a torque transient that can be damaging. 電流瞬間上升至 LRC水平，由此引起的電流瞬變具有破壞性。 How To Calculate Start Torque 如何計(jì)算起動(dòng)扭矩 Start Torque = LRT x Start Current LRC ( ) 2 ( ) 2 300% 600% % = x 263% Motor Start Theory 11 Selecting a motor with low Locked Rotor Current (LRC) and high Locked Rotor Torque (LRT) will: 選擇低鎖定轉(zhuǎn)子電流（ LRC） 和高鎖定轉(zhuǎn)子扭矩（ LRT） 電機(jī)將： Reduce start current. 降低起動(dòng)電流 Increase start torque. 增加起動(dòng)扭矩 Reduce soft starter cost. 降低軟起動(dòng)器的成本 Summary 總結(jié) Motor Start Theory 12 Current rises instantaneously to LRC levels. This causes a current transient that can have undesirable effects on the supply. 電流瞬間上升至 LRC水平，由此引起的電流瞬變可對(duì)電源產(chǎn)生不良的影響 Current gradually falls as motor speed increases. 電機(jī)速度增加時(shí)電流下降。 Reduced Voltage Starting Amplifies Motor Differences 降壓起動(dòng)擴(kuò)大電機(jī)差異 Sample Of Typical 110kW Motors Motor Start Theory 10 Motor LRC LRT TORQUE (%FLC) (%FLT) 3 X FLC A 600 263 B 600 190 C 570 150 D 660 190 Follow the example and calculate the start torque at 3 x FLC for motors B, C amp。 G produce almost the same torque at full voltage. 電機(jī) B和 G在滿電壓情況下產(chǎn)生的扭矩幾乎相同。 LRT同時(shí)運(yùn)轉(zhuǎn) Motor Speed FLC LRC LRT % FL Torque (rpm) (amps) (%FLC) (%FLT) Ef’ncy 3xFLC A 1470 191 600 263 93 B 1475 184 600 190 C 1475 191 570 150 92 D 1480 187 660 190 E 1470 185 550 120 92 36 F 1470 191 670 150 93 G 1480 190 780 200 94 H 1475 182 850 220 I 1480 190 670 120 94 24 Sample Of Typical 110kW Motors Torque developed at 3 x FLC Motor Start Theory 9 Motor Speed FLC LRC LRT % FL Torque (rpm) (amps) (%FLC) (%FLT) Ef’
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