Y-Δ starting:
For a squirrel-cage asynchronous motor in which the stator winding is normally connected in a delta connection, if the stator group is wound into a star at the time of starting, and then connected to the triangle after the start, the starting current can be reduced and the pair can be reduced. The impact of the grid. Such a starting mode is called a star-delta decompression starting, or simply a star-delta starting (Y-Δ starting).
When starting with the star-delta, the starting current is only 1/3 of the original starting directly by the delta connection. If the starting current at the time of direct start is 6 to 7 Ie, the starting current is only 2 to 2.3 times when the star-delta is started. This means that when starting with the star-delta, the starting torque is also reduced to 1/3 of the original direct start by the delta connection. Suitable for applications with no load or light load start. And compared to any other decompression starter, the structure is the simplest and the cheapest. In addition, the star-delta starting method has the advantage that when the load is light, the motor can be operated in star connection. At this time, the rated torque can be matched with the load, which can improve the efficiency of the motor and save power consumption.
