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,if high power motor In the case of the power transformer capacity is not big enough start directly,because of 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 normal work of the electric vehicle motor other equipment in the same supply network.Therefore,the high power motor need to adopt step-down rev Move.For high power motor racing and light load of starting,Y exchange is the most mature used step-down starting boot method.Y exchange start refers to the electricity Motivation starts,the stator windings into a star,in order to reduce the starting voltage,limit the starting current; After waiting for motor starting,and then change the stator windings connect into a triangle, Make the motor run from now on.
Who made triangle connection during normal operation of the stator winding asynchronous motor,the step-down method are available.Motor rev.When moving,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 One third of the delta connection.According to the circuit to control the change of the type of core parts,step-down start can be divided into time relay based in starting and based on PLC control The system change after starting.Practice has proved,based on the starting time relay control it's easy to have a time relay,ac contactor break line,mechanical transmission parts stuck (Y type small startup torque) failure by refusing action and cause cannot step-down start,long arc,arc of cause pumps of interphase short circuit caused by such failure.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 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.PLC based on configuration software Connected to the communication between upper PC to realize the remote control operation,operators can not only improve working environment,and can improve the safety of work.
