Measures to Ensure Normal Startup of the Slurry Pump

To ensure the normal startup of the unit, the following measures can be adopted:

• Minimize the voltage drop at the motor terminals to enhance the motor starting torque, which is proportional to the square of the voltage, ensuring that M (motor) > M (static load).

• To reduce the hydraulic resistance torque M (hydraulic), centrifugal pumps should be started with the valve closed, while axial-flow pumps should be started with the valve open.

• To reduce M (hydraulic), the pump can be started in air. Once it reaches the rated speed, water can then be introduced into the pump. For large submersible pumps, the suction valve can be closed during startup, or compressed air can be used to lower the water level below the impeller before starting. When using this method, attention must be paid to dry friction issues in the wear rings, bearings, and packing. To mitigate this, partial water filling—known as semi-water-filled startup—can be employed.

• For large axial-flow pumps, the motor rotor can be lifted during startup to improve lubrication conditions in the thrust bearing and reduce M (hydraulic).

• For pumps with adjustable blades, the blade angle can be reduced to minimize M (hydraulic)

• Use dedicated startup generators, hydraulic couplings, or similar devices.

• Employ variable frequency drive (VFD) startup.