Liquid pressure monitoring to indicate strainer clogging

A liquid pressure monitoring system for a circuit 120 of a machine includes a flow meter 130 configured to measure a flow rate of liquid flowing through a circuit 120 comprising a strainer 122 and a cooling section 124; a pressure sensor 132 to measure a pressure of a portion of the circuit 120; and a monitoring component 150 for generating an alarm indicating clogging of the portion, in response to a value based on the measured pressure exceeding an expected pressure drop that is based on the flow rate and at least one flow coefficient. The flow coefficient can be that of the strainer and the pressure gauge 132 can measure the pressure drop across the strainer. The value can be the pressure drop across the strainer and the flow coefficient can be based on the geometry of the strainer and on historical data of the pressure drop as a function of the flow rate. The sensor can include an inlet sensor (fig 2, 134) measuring the pressure of liquid entering the strainer and the pressure drop can be the difference between the inlet pressure and an outlet pressure of liquid exiting the circuit, which can be based on historical data of the inlet pressure as a function of the flow rate. The sensor can include an outlet pressure gauge (fig 3, 132) to measure a pressure drop across the strainer. The circuit 120 can be a cooling circuit for the stator of a liquid cooled machine such as an electrical power generator.