The emergency stop button—commonly called the E-Stop—is a critical safety feature found on most decanter centrifuges, including those designed by Centrisys. While it's easy to recognize this large, red button on the control panel, it’s just as important to understand what it does and when to use it. For example, the E-Stop button should only be used in an emergency.
In the video above, we explain the purpose of the E-Stop button and how its use can affect decanter centrifuge operations. The video also explains the important steps that need to be taken after the E-Stop is pressed and what cleaning should be done before the decanter centrifuge returns to normal operation.
The E-Stop button is designed for one thing only: stopping the centrifuge immediately during an emergency. Pressing this button cuts off power to the centrifuge’s motors and control systems, including the hydraulic back drive and lubrication system.
Unlike a normal shutdown sequence—where the centrifuge’s deceleration is carefully controlled—an E-Stop cuts power instantly, causing the centrifuge to coast to a stop.
This coasting process can take up to an hour, especially in larger or higher-speed units. Because power is cut so suddenly, the decanter centrifuge will retain any solids inside the bowl. If the E-Stop is used when it’s not necessary, these leftover solids can create an imbalance on startup. These solids may trigger vibration alarms or result in additional wear and downtime.
Additionally, some voltage may still be present in the motor wiring after the E-Stop is pressed. Even though the power is cut, the motor can generate electricity while it coasts. Operators should never touch wires during this period.The E-Stop button should only be used in true emergency situations,, such as when immediate action is required to protect personnel, equipment or the surrounding environment. These scenarios include:
Taking the time to perform a controlled shutdown through the control panel could increase the danger in these situations. The E-Stop provides a fast, accessible way to cut power instantly and allows operators to respond to emergencies.
Because the E-Stop causes the centrifuge to coast to a stop, it leaves solids behind and potentially skips critical shutdown processes. Because of this, it should never be used as a shortcut for routine operations.
A common misconception is that using the E-Stop will shut the centrifuge down more quickly. This is not necessarily true as a controlled deceleration of a standard shutdown is usually faster and safer.
Operators should avoid using the E-Stop in the following situations:
Should a non-critical alarm occur, the operator should silence it. A non-critical alarm occurs when there is an underlying issue that needs to be addressed. Resetting an alarm without resolving the root cause will cause it to trip again.
If the issue is unclear or the operator cannot access the shutdown screen, it’s best to contact Centrisys/CNP field service for assistance rather than using the E-Stop.
You can reset the decanter centrifuge once the emergency has been handled and it is safe to resume operations. A specific reset sequence must be followed to bring the centrifuge back online.
Even if the decanter centrifuge has not come to a full stop, you can follow the below process to reset the equipment after an emergency shut-off:
This means checking the main power source—typically controlled through your facility’s main breaker—and the main disconnect, which is located on the right side of the centrifuge control panel.
Resetting requires either pulling the button out or rotating it clockwise, depending on the specific button style installed. This will release the button and prepare the control system for reactivation.
The yellow reset button is located near the E-Stop. This re-engages the master control relay (MCR), which restores control power to auxiliary equipment.
With the MCR active, go to the control screen and clear any flashing banner alarms that may still be present. Now, it's time to restart the centrifuge’s critical systems manually. This includes the hydraulic back drive pump unit, the lubrication system (for machines with air/oil or recirculated lubrication) and the bowl flush system. These systems need to be running before the centrifuge is restarted.
Reactivating these systems is a critical part of the reset procedure. Failure to reactivate the lubrication and hydraulic systems could cause the rotating assembly to continue moving without proper lubrication. This condition can lead to accelerated bearing wear and potential damage to the Rotodiff.
Whenever the E-Stop is used, Centrisys strongly recommends running a Cleaning-In-Place (CIP) cycle before restarting the centrifuge. This additional step helps to flush out any residual solids left in the bowl during the uncontrolled stop and ensures the decanter centrifuge is balanced and clean before beginning a new run.
The CIP also provides a controlled method of completing the shutdown process and serves as a final check before safely restarting the decanter centrifuge. Skipping this step increases the risk of imbalance alarms and unnecessary wear on internal components.
If you have questions about resetting your decanter centrifuge after an emergency shutdown, we are here to help. Our expert team can guide you through the correct procedures and help identify signs requiring professional attention. Contact us today.
Q: What does the E-Stop button do?
A: When pressed, the E-Stop button immediately cuts power to all motors and control devices, stopping the lubrication and hydraulic back drive systems and causing the centrifuge to coast to a stop. It should only be used in emergencies.
Q: Does the E-Stop shut down the centrifuge faster than a normal shutdown?A: No. A normal shutdown often stops the centrifuge faster because it uses controlled braking. The E-Stop cuts power, but the machine coasts to a stop, which can take up to an hour.
Q: Can using the E-Stop cause damage to the decanter centrifuge?
A: Yes, if used improperly. Because it leaves solids inside the bowl and shuts off lubrication, it can lead to imbalance and accelerated wear during the next startup.
Q: Is it safe to touch motor wires after pressing the E-Stop?
A: No. Even after the E-Stop is pressed, the centrifuge may still generate voltage as it coasts down. Do not touch wires until the system has completely stopped and been verified as de-energized.
Q: What should I do if the E-Stop is pushed accidentally?
A: When this occurs, the operator should follow the entire reset process, re-engaging the master control relay and restart the auxiliary systems. If you're unsure, call Centrisys service for assistance.
Q: Do I need to perform a CIP after using the E-Stop?
A: Yes. Running a Cleaning-In-Place (CIP) cycle helps remove residual solids and ensures the centrifuge is balanced and clean before the next run.
Our goal at Centrisys/CNP is to help customers run their equipment safely and efficiently. Our field service team is available to assist if you’re ever unsure whether to use the E-Stop, encounter a persistent alarm, or need help restarting a centrifuge after an emergency stop.
Contact Centrisys/CNP experts online or call 262-425-9704. We service all brands of decanter centrifuges, not just our own, and can help troubleshoot, repair or maintain your system as needed.