US Patent 9650871 Safety indicator lights for hydraulic fracturing pumps

A hydraulic fracturing system includes an electrically powered pump that pressurizes fluid, which is piped into a wellbore to fracture a subterranean formation. System components include a fluid source, an additive source, a hydration unit, a blending unit, a proppant source, a fracturing pump, and an electrically powered motor for driving the pump. Also included with the system is a signal assembly that visually displays operational states of the pump and motor, thereby indicating if fluid discharge lines from the pump contain pressurized fluid. The visual display of the signal assembly also can indicate if the motor is energized, so that the discharge lines might soon contain pressurized fluid.