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Control System for an asphalt plant to adjust the speed of 6 conveyors
- Material handling
- Asphalt
- Batching
One-time system
- Provide variable-speed control via VFDs of 6 AC motors (each 3-Phase, 460V, 3Hp)
- Motors will be located at various points in the plant, some far away from the electrical control panel
- Existing equipment includes contacts to determine if material is backing up on the conveyor. When material backs up the operator should be notified
- The system should have several modes of operation including: Enabled, Disabled and Off
- Speed of each conveyor must be set independently but a master speed control must automatically increase or decrease each speed proportionally
- AMPS designed and built a PLC-based control system with integrated color touch-screen from Unitronics. This made it easy to include features the features described above.
- Variable-Frequency Drives (VFDs) were used to control each motor independently and provide control over motor speed.
- Line Reactors were installed on the output side of each VFD to reduce harmonics and transients due to the long-distance motor leads.
- We provided a speed dial for each conveyor's VFD and one Master Speed Dial to adjust all six conveyors according to the ratio set by each one individually.
- The PLC/Touch-Screen was programmed for intuitive operation and control over timer settings and other adjustments. The display also provides constant updates on the status of the system and each conveyor along with displaying warnings as appropriate.
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