Control of Pumps Operation Using Frequency Converters
When two or more pumps operate in tandem, their operation is controlled by a frequency converter. This allows installing frequency converters on each pump, providing maximum flexibility in operation, or using just one converter connected to multiple motors.
Principle of Tandem Pump Operation
In a situation where the first pump reaches its maximum speed and maintains it for a certain time, the second motor can begin operation. After this, both motors can work simultaneously. This can be programmed in various ways:
- both motors operate at a floating speed;
- one operates at maximum, and the other adds power to the necessary level.
Additionally, a star-delta connection scheme can be used for the second pump. When the frequency converter operates at maximum, it can utilize a star-delta connection, gradually reducing speed to provide the exact power needed by the system. As before, all these scenarios have their advantages and disadvantages that require detailed study in each specific case.
Control of Pumps Under Variable Water Level Conditions
In many wells, the water level is dynamic, and the correct pump supply level is unknown, leading to many pumps operating at points that significantly differ from optimal. AC frequency converters can control the pump in the well by regulating pressure and water supply.
Using a converter can extend the lifespan of the pumps, as they will operate closest to their optimal points. If the correct volume of water is pumped from the well, and according to the results of 48-hour tests, the flow level remains stable, then such a well will operate longer than with uncontrolled water supply.