Differential pressure regulation for pump system - shifts pump motor operating point to bring motor current into required range

摘要

The differential pressure regulation uses a microprocessor (1) supplied with a voltage signal proportional to the actual current (IH) through the main pump motor winding (L1), for comparison with a stored range of required values addressed via the motor operating voltage and the detected motor operating point. When the current is outside the required range, the motor is adjusted to a different operating point, to bring it back into the required range. Pref. the actual motor winding current (IH) is provided via a series shunt resistance (RS) and fed to the microprocessor via an A/D converter (2), the motor operating point adjusted via switches (T1...T4) associated with an auxiliary motor winding (L2). ADVANTAGE - Allows differential pressure to be held constant for different flow rates.