| 摘要 |
Means for continuously shut-down operation of and enclosed motor-compressor unit for refrigeration or heat pump service when the refrigerant-oil mixture therein reaches a predetermined degree of contamination by conductive particles comprises the provision of a normally closed switch in the motor energizing circuit, a relay which when energized opens the switch, in immersing a pair of spaced electrodes in the mixture, in connecting the electrodes and a capacitor in series across a D.C. power source, in connecting a unidirectional solid state switch and the relay in parallel with the electrodes and capacitor and in providing voltage responsive gating means for turning on the switch in response to a predetermined charge on the capacitor, and in the provision of a normally open fusible switch responsive to fuse and close in response to a predetermined high motor temperature and through relay means opens a second normally closed switch in the motor energizing circuit.
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