"Three phase induction motor (ZDYR) with conical rotor soft start" is introduced in detail.

一、軟啟動設備的工作原理在三相電源與電機間串入三相反并聯晶閘管（可控硅整流器），利用晶閘管移相控制原理，啟動時電機端電壓隨晶閘管的導通角從零逐漸上升，電機轉速逐漸增大，直至達到滿足啟動轉矩的要求而結束啟動過程，此時旁路接觸器接通（避免電機在運行中對電網形成諧波污染，延長晶閘管壽命），電機進入穩態運行狀態，停車時先切斷旁路接觸器，然后由軟啟動器內晶閘管導通角由大逐漸減小，使三相供電電壓逐漸減小，電機轉速由大逐漸減小到零，停車過程完成。啟動時，使晶閘管的導通角從0開始，逐漸前移，電機的端電壓從零開始，按照預設函數關系逐漸上升，直到達到滿足啟動轉矩而是電動機順利啟動，再使電機全電壓運行。從工作原理上看，軟驅動器實際上是一個調壓器，輸出只改變電壓，并沒有改變頻率。這一點與變頻器不同。

The working principle, a soft start device in three-phase power supply and motor series three-phase anti parallel thyristor (SCR), using the principle of thyristor phase control tube, when starting the motor terminal voltage with thyristor conduction angle gradually increased from zero, the motor speed increases gradually, until meet the start torque requirements end start process, the bypass contactor is on (to avoid formation of motor harmonic pollution on the grid in the operation of the thyristor is prolonged life), a motor is in steady state, the first cut off the bypass contactor when parking, and then by the soft starter in the conduction angle of the thyristor is gradually reduced, the three-phase the power supply voltage decreases, the motor speed is gradually reduced to zero, the stopping process is completed. When starting, the thyristor conduction angle from the beginning of 0, will move to the motor terminal voltage from zero, according to the preset function gradually increased, until meet the starting torque but motor start smoothly and then make full voltage operation of motor. From the working principle, the soft drive is actually a voltage regulator, the output only changes the voltage, and does not change the frequency. This is different from the frequency converter.

二、軟啟動設備的優點

Two, the advantages of soft start equipment

1）起動時無沖擊電流，通過逐漸增大晶閘管導通角，使起動電流從零線性上升至設定值；

1) no impulse current is started, and the turn-on angle of thyristor is gradually increased, the starting current is increased from zero to the set value;

2）屬恒流起動，軟起動器可引入電流閉環控制，使電動機在起動過程中保持恒流，確保電動機平穩起動；

2) is a constant current starting, soft starter can be introduced into the current closed-loop control, so that the motor in the starting process to maintain a constant current, to ensure the smooth start of the motor;

3）可根據負載情況及電網繼電保護特性選擇，能自由地無級調整至最佳的起動電流。

3) according to the load condition and the power system relay protection characteristic, it can freely adjust to the best starting current.

4）可以頻繁的啟動電動機，軟啟動允許10次／小時，而不致電動機過熱。

4) can frequently start the motor, soft start to allow 10 times / hour, and not cause motor overheating.

（籠型電動機傳統的減壓起動方式有：Y-△起動、自耦減壓起動、電抗器起動等，皆屬于有級減壓起動，其缺點是在起動過程中會出現二次沖擊電流。）

(starting cage motor traditional decompression: Y- delta starting, start and self coupling decompression starting reactor, all belong to the class of starting the drawback is, in the process of starting impact current will appear two times.)