Before replacement
After replacement
Brief overview
This is a control panel that controls a 30KW Shredder Machine, and a 1.5KW conveyor motor. Initially, our customer had some problems with the old panel, and they were unable to access the Siemens PLC to check the control issue. The shredder machine is started by a star-delta starter while the conveyor motor uses direct online (DOL). When there is a jam in the shredder, the operator will need to stop the shredder machine, and press reverse mode to start the shredder in the opposite direction in order to clear the debris. This process is all done manually, and the operator has to go back and forth to the machine and the control panel.
Our proposal
We proposed a new design to our customer to make it more automatic. Incase of a jam in the shredder, the shredder and conveyor motor will stop, and the shredder will automatically start in the reverse direction and turn for about 10 seconds. This timing can be set on our Schneider Smart Relay, in the event where the operator requires more time to clear the debris. After the reverse operation, the shredder and conveyor motor will restart.
Current Sensing Relay
How does one know whether the shredder machine is jammed?
For this, we used a current sensing relay to detect high current in the shredder motor. If the shredder machine operates higher than its full-load current, means the shredder machine is likely jammed and unable to turn. Thus, there is a surge in current, to increase the torque supplied to the motor.