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OPERATING INSTRUCTIONS
AUTOMATIC SHUTDOWN
The centrifuge has built-in safety features to protect the equipment. These features will result in
automatic shutdown of the centrifuge before damage occurs. The following paragraphs describe
these automatic shutdowns.
Excessive Vibration
Excessive vibration of the centrifuge will cause the vibration switch to interrupt electric power to
the centrifuge run relay, shutting down the machine. Such excessive vibration may occur during
startup or normal operation due to slumping of the wall cake or other unbalanced condition of the
bowl. The machine may be re-started by pressing the reset button on the vibration switch and
then using the Normal Startup procedure above.
If the machine continually trips during normal startup, flush the bowl with fresh water while running
the automatic cleanout routine.
Main Bearing Temperatures
Temperature sensors are installed on the liquid and solid end main bearings and connected to the
PLC. Bearing temperatures are continuously displayed on the Operation screen. An alarm
message is displayed on the control panel when bearing temperature exceeds 225°F (107°C). If
temperature rises to 250°F (120°C), a fault message appears and the centrifuge is shut down.
Excessively high bearing temperatures usually indicate bearing failure, which can result from
inadequate or excessive lubrication, contamination, or severe wear. Refer to Section 5 for main
bearing replacement procedure.
Excessive Bowl Speed
A sensor that detects the rotational speed of the bowl provides an input to the PLC that produces
a continuous display of actual bowl speed on the Operation and Bowl VFD screens. A fault
message is displayed and the centrifuge is immediately shut down if speed rises to 3100 RPM. To
re-start the centrifuge, allow the bowl to coast to a complete stop, and check for and remove the
cause of excessive speed (refer to Section 5). After correcting defect(s), re-start the machine
using the Normal Startup procedure above and re-check speed.
EMERGENCY SHUTDOWN
To stop the centrifuge in case of emergency, press the EMERGENCY STOP button on the control
cabinet, select STOP on the Operation screen, or open the fused disconnect supplying electric
power to the machine.
Pressing EMERGENCY STOP immediately removes power from the bowl, conveyor, and pump
motors, allowing the bowl to coast to a stop. This may take more than 15 minutes depending on
the bowl speed and amount of material inside the bowl. To stop the bowl faster, press the STOP
button on the Operation screen or display the Bowl VFD screen, and press the BOWL IS
COASTING TO A STOP button. However, before pressing this button, all alarms/faults must be
cleared.
01 Aug 11
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DE-1000LPVFDCentrifuge