Three-phase ac motor

Three-phase ac motor is widely used in modern industrial and agricultural production in our country,for the development of the society,the progress provides a great convenience.However,the high power motor if the electricalmotor1.blogspot.com power supply transformer capacity is not big enough Under the condition of direct start,due to the asynchronous motor starting current is big,can make the power transformer output voltage has fallen dramatically,not only reduce the starting torque of motor itself,can also affect the same supply network In the normal work of the other devices.Therefore,the high power motor need to adopt step- down start.For high power motor no-load and light load of starting,Y exchange start is the most used Mature step-down start method.Y exchange start refers to the motor start,the stator windings into a star,in generator rotor and statororder to reduce the starting voltage,limit the starting current; After waiting for motor starting,and then put the stator winding Groups convert into a triangle,making the motor running from now on.Who made triangle connection during normal operation of the stator winding asynchronous motor,the step-down method are available.Motor starts,Connect into a Y shape,start in each phase of the stator winding voltage only delta connection,starting current for 1/3 of the delta connection,starting torque is only 1/3 of the delta connection.According to the circuit Core components of the type of control switch,step-down start can be divided into time relay based in starting and exchange starting based on PLC control.Practice has proved,based on the starting time relay control capacity Time relay,ac contactor is seen disconnection,mechanical transmission parts stuck (Y type small startup torque) refusing action and cause cannot step-down start,caused by the failures of long arc,arc of cause of lead The interphase short circuit fault,etc.Configuration software is a kind of data acquisition and process control of specialized software,it is in the level of automatic control system monitoring layer 6v electric motor software platform and development environment,using flexible Configuration mode,to provide users to quickly build industrial automatic control system for monitoring function,general level of software tools.So based on PLC and configuration software of communication between the PC machine connection To realize the remote control operation,operators can not only improve working environment,and can improve the safety of work.