A control module for a refrigeration system includes a startup mode control module that receives an off time of a compressor and an ambient temperature, determines whether the off time and the ambient temperature indicate that the compressor is in a flooded condition, and selects, based on the determination, between a normal startup mode and a flooded startup mode. A compressor control module transitions from the flooded startup mode to the normal startup mode after a predetermined period associated with operating in the flooded startup mode and operates the compressor at a first speed in the normal startup mode and operates the compressor at a second speed less than the first speed in the flooded startup mode.

A control module for a refrigeration system includes a startup mode control module that receives an off time of a compressor and an ambient temperature, determines whether the off time and the ambient temperature indicate that the compressor is in a flooded condition, and selects, based on the determination, between a normal startup mode and a flooded startup mode. A compressor control module transitions from the flooded startup mode to the normal startup mode after a predetermined period associated with operating in the flooded startup mode and operates the compressor at a first speed in the normal startup mode and operates the compressor at a second speed less than the first speed in the flooded startup mode.

Systems and methods for operating hydraulic fracturing units, each including a hydraulic fracturing pump to pump fracturing fluid into a wellhead and an internal combustion engine to drive the hydraulic fracturing pump, may include receiving signals indicative of operational parameters. The systems and methods also may include determining an amount of required fracturing power sufficient to perform the hydraulic fracturing operation, determining an available power to perform the hydraulic fracturing operation and a difference between the available power and the required power, and controlling operation of the hydraulic fracturing units based at least in part on the power difference. When the power difference is indicative of excess power available, the system and methods may include causing at least one of the hydraulic fracturing units to idle, and when the power difference is indicative of a power deficit, increasing a power output of at least one of the hydraulic fracturing units.

Systems and methods for operating hydraulic fracturing units, each including a hydraulic fracturing pump to pump fracturing fluid into a wellhead and an internal combustion engine to drive the hydraulic fracturing pump, may include receiving signals indicative of operational parameters. The systems and methods also may include determining an amount of required fracturing power sufficient to perform the hydraulic fracturing operation, determining an available power to perform the hydraulic fracturing operation and a difference between the available power and the required power, and controlling operation of the hydraulic fracturing units based at least in part on the power difference. When the power difference is indicative of excess power available, the system and methods may include causing at least one of the hydraulic fracturing units to idle, and when the power difference is indicative of a power deficit, increasing a power output of at least one of the hydraulic fracturing units.

A method and computer program product for defining a PWM drive signal having a defined voltage potential. The PWM drive signal has a plurality of “on” portions and a plurality of “off” portions that define a first duty cycle for regulating, at least in part, a flow rate of a pump assembly. At least a portion of the “on” portions of the PWM drive signal are pulse width modulated to define a second duty cycle for the at least a portion of the “on” portions of the PWM drive signal. The second duty cycle regulates, at least in part, the percentage of the defined voltage potential applied to the pump assembly.

A method and computer program product for defining a PWM drive signal having a defined voltage potential. The PWM drive signal has a plurality of “on” portions and a plurality of “off” portions that define a first duty cycle for regulating, at least in part, a flow rate of a pump assembly. At least a portion of the “on” portions of the PWM drive signal are pulse width modulated to define a second duty cycle for the at least a portion of the “on” portions of the PWM drive signal. The second duty cycle regulates, at least in part, the percentage of the defined voltage potential applied to the pump assembly.

The present invention relates to a method of loading a fluid into a fluidic element, wherein the method is performed in a fluidic system comprising the fluidic element, wherein the method comprises determining a volume that has flown into the fluidic element since a start time t.sub.start, and at a switching time t.sub.switch, switching the fluidic system to an operating state to stop flow into the fluidic element. The present invention also relates to a fluidic system configured for performing the method, and to a corresponding computer program product.

A method for controlling outputs of electric motors includes the steps of (a) providing an electric motor including a stator winding unit selected from first to fourth winding groups, each of the winding groups having at least a primary winding with a first number of poles and a first rated power, and at least a secondary winding with a second number of poles being the same as or different from the first number of poles and a second rated power being the same as or different from the first rated power; and (b) providing a control device respectively coupled with the electric motor and an external electrical power source for sensing a needed loading state of the electric motor and suppling a required connection relationship between the stator winding unit and the external electrical power source based on the needed loading state sensed by the control device.

A method for controlling outputs of electric motors includes the steps of (a) providing an electric motor including a stator winding unit selected from first to fourth winding groups, each of the winding groups having at least a primary winding with a first number of poles and a first rated power, and at least a secondary winding with a second number of poles being the same as or different from the first number of poles and a second rated power being the same as or different from the first rated power; and (b) providing a control device respectively coupled with the electric motor and an external electrical power source for sensing a needed loading state of the electric motor and suppling a required connection relationship between the stator winding unit and the external electrical power source based on the needed loading state sensed by the control device.

A lubricator package for intermittently delivering a lubricant to lubrication points on packing on a high-pressure reciprocating pump, a frac pump is described. A preferred package includes a large (e.g., 10 gallon) capacity reservoir; a three or five outlet pump; a common manifold receiving oil from the large capacity reservoir and supplying oil or grease to the pumps; a mounting stand supporting the large capacity reservoir and the five outlet pump; and an optional a control package providing low level monitoring of lubricant flow and controlling the pump providing a pump stroke counter or timer.