What are the starting methods of pumpssubmersible progressive cavity pump
The submersible progressive cavity pump is compact and easy to use. With the development of electric motor, sealing technology, control and protection technology, the submersible progressive cavity pump has developed rapidly. Since the submersible progressive cavity pump works submerged, the design of its control and protection system is especially important in order to achieve safe, intelligent and efficient operation of the submersible progressive cavity pump. Today, we would like to introduce the starting method of submersible cavity pump, and hope it can help you.
Motor starting current is very high, sometimes more than 5~7 times the rated current, such a large current often through the motor winding, may produce damage to the motor, and will make the grid voltage drop. The motor can be started by full voltage direct start or reduced voltage start according to the power supply and specific electrical equipment. The protection apparatus should not be operated when starting to ensure the motor start smoothly, and the voltage drop caused by the inrush current to the line should not be too large to avoid affecting the normal operation of other equipment. submersible progressive cavity pump starting methods mainly include direct starting, autotransformer starting and star-delta starting.
(1) When starting a small capacity submersible motor, the starting current is not large, and the impact on the power grid is small, so direct starting is often used, with simple equipment, easy maintenance, short starting time and large starting torque, which is the cheapest method.
(2) If the power of submersible progressive cavity pump is larger, or the capacity of power supply transformer is smaller, the starting current can be reduced by reducing voltage, but the starting torque of motor will be significantly reduced.
For autotransformer step-down starting, the primary side of the autotransformer is connected to the power supply, and the secondary side (i.e. part of the primary winding) is connected to the stator winding of the motor. When the motor speed is basically stable, the autotransformer is removed. This method can reduce the starting voltage and starting current of the motor. In order to meet different requirements, autotransformers are generally equipped with voltage taps of 0.65 or 0.80 supply voltage.
In the star-delta switching method, the three phase windings of the motor stator will be connected to star to start, and then switched to triangle to normal operation when the motor speed is basically stable.
(3) When frequency conversion starting, the 50 Hz constant frequency AC power of electric power distribution network is turned into low frequency AC power for submersible pump starting, the motor starts smoothly, the starting current is small, with high efficiency driving performance and good control characteristics.