Common water pump F.A.QBelow are some of the most common questions from our clients regarding pumps. Need more technical support? Contact our technician here>>>
Q: If the centrifugal pump "runs backwards", can it really work?
A: Somewhat. If the motor and pump are running backwards, the pump will usually still be able to move the water and the water will flow through the pump in the normal direction.
The centrifugal pump accelerates the moisture at the tip of the impeller blades. When the impeller is running backwards, the centrifugal force will still accelerate the water - albeit much less efficiently. Pumps that run backwards will deliver less water at lower pressures and will typically consume less power. If the impeller is threaded onto the shaft, it can be unscrewed when running backwards.
Q: My pump noise big. What is the cause of the noise?
A: It is very likely to be cavitation. Cavitation means the formation of cavities or bubbles in the liquid being pumped. Symptoms of cavitation include excessive noise and vibration as well as loss of capacity, pressure and efficiency. Cavitation can cause damage to the pump. Solutions include changing operating parameters and even replacing the pump with a pump that is more suitable for the application.
Q: Why my pump can't priming?
A: The pump may not be delivered correctly, or there may be a net positive suction head (NPSH) problem associated with temperature or fluid type. Unless your pump is a “self-priming” pump, it will not start unless the pump is full of water and there is no air inside to block the pump.
Q: If I add a bigger motor to the pump, will it pump more?
A: The amount of water and pressure (head) generated by the centrifugal pump is related to the speed, impeller diameter and the size of the impeller blades.
Q: Can I add a mechanical seal to my packed centrifugal pump?
A: Maybe. There must be enough physical space to install one. Sometimes you may need to do some machine work on a "real" surface that has corroded over time or has never been processed because the pump is designed to be packed.
Q: My pump starts and stops frequently. Will damage the motor?
A: Maybe. Each time the motor starts, the winding see up to 10 times the inrush current of the nameplate amplifier (locking rotor code M). The motor dissipates energy in the form of heat. If the motor is started multiple times, the accumulated heat may damage the motor.
Q: If I place a higher speed motor on the centrifugal pump, will it pump more?
A: It will output more, but it may overload the motor. If the motor speed is doubled from 1800 RPM to 3600 RPM, the power required by the centrifugal pump will actually increase by a factor of 8. Increasing the pump speed may also cause the pump to pressurize beyond the safe working pressure and overload the shaft and bearing. Adding an impeller are better.
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