Fluid pressure operated switch with solid state components - detecting variations in motor current, voltage and power factor as well as interval duration during which motor is energised

摘要

A diaphragm responsive to fluid pressure operates a snap-action switch connecting the motor (76) to a source of current, via moving contacts (20) and stationary contacts (36-39). The motor is protected against water system failures by control components located in a front chamber (110), including a relay (150), a current detector (152) and control logic circuit (154). Red and yellow LEDs (156,158) with flashing and steady indications give warnings of fault conditions such as no-load, r rapid cycling, low or high voltage, overload or extended run. A desired operating condition of the motor can be entered into nonvolatile memory by means of a front-panel pushbutton (160). The logic circuit (154) interrupts or prevents energisation of the motor when any variation in its operating conditions exceeds a preprogrammed limit.