COMPRESSOR PROTECTION DEVICE

摘要

PURPOSE:To allow sure monitoring by directly detecting gas pressure of a compressor with a flow switch to compare same with a comparative reference and thereby to surely provide a protection output, and self-monitoring abnormality in a protection device itself. CONSTITUTION:A flow switch 1 serves to detect gas pressure of a compressor as an electrical signal, and a comparating circuit 2 serves to compare a detection signal from the flow switch 1 with a comparative reference signal to detect whether or not the compressor generates normal pressure. A driving circuit 3 serves to amplify a detection output from the comparating circuit 2 and provide a protection output for stopping operation of the compressor upon receiving an abnromality detecting signal of the compressor. A disconnection detecting circuit 4 serves to detect disconnection in the flow switch 1 and that between the flow switch 1 and the comparating circuit 2. A short-circuit detecting circuit 5 serves to detect short-circuit of a wiring. Thus, more sure monitoring and protection may be possible by self-monitoring abnormality in a protection device itself.