EE Partners, LTD. "Overview of Oilfield Harmonics." Nov. 2011:, "What are harmonics and where do they come from"....Power grids in the US are drive by massive generating plants "sychronized" with common volate and 60Hz frequency.
Pump Control Panel
EE Partners, LTD. "Beam Pumping Unit Control Panel." April 2014:, "Elementary Diagram for Beam Pump Control Panel"....GENERAL NOTES: 1. ALL ELECTRICAL EQUIPMENT AND COMPONENTS INSTALLED SHALL BE LISTED AND LABELED FOR ITS USE AND AREA CLASSIFICATION(NEC 110-3).
EE Partners, LTD. "651R Training Card v3.5." Feb 05 2014:, "INDICATING LIGHTS"....NORMAL OPERATING LIGHTS: A. RECLOSER ENABLED LED ON B. 120 VAC SUPPLY TO RECLOSER LED ON C...