System Controls, Inc - Electric Conveyor Winch

Longwall Pump Controls

Longwall Pump controls are transitioning from across-the-line motor starters to AC Drives. Multiple pumps are used in combination to provide the flow required for the application load. With PLC and HMI controls the system is easily configured to determine how many pumps and the order of which pumps are used. Utilizing varible frequency drives eliminates power system stress and allows the user to operate the pumps at peak operating effciency.

Low voltage pumps (480-600 VAC) up to 1000 HP are typically used in this application.

ENHANCED CONTROL OF PRESSURE REGULATION
Pressure regulation is controlled by varying the speed of the pumps rather than cycling a full-voltage pump on or off instantaneously or by pump discharge throttling. Both of these control methods cause excessive strain on the power grid and are not energy efficient. The VFD provides precise regulation of pressure throughout the entire pump curve. Utilizing VFD control effectively eliminates the issues associated with large motor across-the-line starts and allows the pumps to operate at near unity power factor improving overall power system energy efficiency.

REDUCTION OF HYDRAULIC SHOCK
By load sharing VFDs and providing better regulation of system pressure, hydraulic shock is virtually eliminated. This reduction in hydraulic shock extends the life of pumps, hoses, and fittings requiring fewer pump rebuilds and hose repairs.

INCREASED RELIABILITY
Use of variable speed drives eliminates electro-mechanical contactors and provides real-time diagnostic data for use in preventive maintenance programs. When a spare VFD is incorporated into the design the PLC controls alternately selects VFDs and pumps providing even pump wear and system redundancy.

ADDITIONAL FEATURES
VFDs in combination with PLC based controls provide on-line troubleshooting assistance, collection of historical data, and real-time reporting of alarms and warnings. The VFDs may be sized so that they are compatible with other VFDs used in the mine making training and stocking of spares much easier and less costly.

In addition to these benefits you get the highest quality design, construction, and service that you have come to expect from System Controls, Inc.