Pump control responsive to voltage-current phase angle
US5362206A · kind A · utility
138Cited by
34References
20Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jul 21, 1993 |
| Grant date | Nov 8, 1994 |
| Priority date | — |
| Expiry date | Jul 21, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H3/382
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A pump-off controller checks for pump-off by examining the relative phase relationship between AC voltage and AC current supplied to an inductive, alternating current, electric motor driving a cyclically operated mechanical system having a walking beam for raising and lowering a subsurface pump by means of a string of sucker rods. When the phase angle between AC voltage supplied to the motor and AC current drawn by the motor exceeds a predetermined value at selected points or regions of the pumping stroke, the pumping system is shut down for a predetermined time.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.