04021700 is referenced by 84 patents and cites 10 patents.

Complete protection of a three-phase submersible pump motor, such as the type used downhole in an oil well, is obtained with a solid state digital logic control system that monitors each of the three phase currents and shuts the pump motor down if any of those phase currents indicates either an underload or overload condition. Time delays are introduced before shutdown to avoid undesired nuisance shutdowns otherwise caused by transient or momentary conditions. When the pump motor is de-energized in response to an underload condition, it is automatically restarted after a predetermined time delay. All of the delay functions are precisely determined by division of the power line frequency. Downhole pressure and temperature are also sensed and if they become excessive the motor is automatically de-energized to prevent overheating. The presence of an auxiliary physical condition, such as filling up a retaining tank, also causes the pump motor to be turned off.

Title
Digital logic control system for three-phase submersible pump motor
Application Number
5/583718
Publication Number
4021700
Application Date
June 4, 1975
Publication Date
May 3, 1977
Inventor
David R Ellis Anwyl
Long Beach
CA, US
Agent
James E Tracy
Assignee
Borg Warner Corporation
IL, US
IPC
H02H 7/09
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