Method and apparatus for detecting surge in centrifugal compressors driven by electric motors
US4581900A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 24, 1984 |
| Grant date | Apr 15, 1986 |
| Priority date | — |
| Expiry date | Dec 24, 2004 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H7/0854
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A surge detection apparatus for use in a refrigeration system having a centrifugal compressor driven by an electric motor includes a first pressure transducer for sensing a condenser pressure and a second pressure transducer for sensing an evaporator pressure. A first bandpass digital filter responsive to the condenser pressure and the evaporator pressure is provided for generating a first signal representative of the rate of change of the pressure developed across the compressor. A current transformer is used to sense a current in the electric motor driving the compressor. A second bandpass digital filter responsive to the motor current is provided for generating a second signal representative of the rate of change of the RMS current being drawn by the compressor drive motor. A third signal representative of a differential pressure threshold and a fourth signal representative of a first motor current threshold and a second motor current threshold are provided. A computing device responsive to the first through fourth signals indicates when a valid surge is occurring in the compressor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.