One of the best ways to discover potential damage to your pool pump is by noticing excessive vibrations. These vibrations could be a result of embryonic faults, component failures or poor running conditions. This is why it is important to monitor the vibration levels of your pool pump regularly. Your pool pump’s dependability, safety, and production capability can be improved through regular monitoring. It is critical to understand the causes of the excessive vibrations and how to correct them. This post will focus on determining the root causes of pool pump vibrations.
Many conclude that vibrations are caused when the rotor of the pool pump is out of place. But it may not be the imbalance of the rotor; there are many other causes. There are ways to identify the source of the vibrations because each of them has specific frequency signatures. Let’s take a look at some of them:
1. Pump Bearing Problems
Bearings are placed onto the pool pump motor to help reduce the friction as the electromagnets make the motor shaft spin. But when the rolling element starts to wear, vibrations can be triggered. The number of bearing balls or rollers is what determines the frequency signature of the vibration. This frequency is best determined by the manufacturer of the bearing part of a pool pump. An effective way to prevent the failure of the pump bearings is to lubricate the bearings with recommended oils regularly.
2. Bent Pump Shaft
A bent shaft of a pool pump also causes high axial vibrations in the pump. If the bend is near the shaft center, notable vibrations may occur at 1X RPM. However, this is not as common as when the bend is at or near the coupling; it can occur at 1X RPM. Dial indicators are best used to identify a bent shaft in a pump.
3. Misalignment of the Shaft
Some vibrations are normal, but it sometimes takes a professional repair technician to determine the level and cause of excessive vibrations in a pool pump, especially if a shaft misalignment causes the excessive vibration. They can also tell how far it will affect the performance and reliability of the pool pump. It’s not too easy to detect a misalignment of the shaft; there’s hardly any sensor that can be placed on a pump to determine the level of force being used. However, you can generally diagnose a pool pump for shaft misalignment if you notice any or a combination of any of the following; excessive oil leaks at the bearing seals, heat of the discharge oil, excessive coupling failures, breaking or cracking of shafts, high temperatures near the casing or bearings, excessive axial or radial vibrations, and loose coupling, among others.
4. Imbalance of the Pump Impeller
You cannot avoid episodes of vibrations if the impeller of your pool pump is imbalanced. An imbalance of the impeller makes your pool pump seem misaligned, overheated, to have a bad bearing. Ultimately, you begin to sense some vibrations too when this occurs. Apart from these problems caused by an imbalanced impeller, this condition can also be dangerous in one or more of the following ways; seizing of the pool pump, failure of the mechanical packing, shaft deflection, etc. A centralized pool pump impeller causes more of a force imbalance than couple imbalance. In this case, we are looking at radial directional vibration with amplitude speed of about 1X RPM.
When the net positive suction head is insufficient, pump cavitation sets in. Usually, the absolute pressure of the liquid at the impeller shouldn’t approach the liquid vapor pressure in a swimming pool pump. This is what prevents pockets from forming and collapse as they pass through the impeller. But when the contrast happens, cavitation occurs, thereby causing vibrations in a pumping system. In simpler terms, cavitation happens when water is lower than the recommended amount within a time frame. In other words, the pump is starved of water while the impeller spins. This can cause a loud clattering sound, and in turn, excessive vibrations. The sound of a pool pump vibration caused by cavitation can be identified by a seeming rumbling rock sound or distinctive popping. Beyond the vibrations caused, more energy is expended by the pump, and potential damage is set to occur if you do not quickly take care of cavitation.
6. Pump Flow Pulsation
It’s a really not too good for a pump to be operating near its shut-off head. This occurs when the pump runs with the discharged valve closed. If this happens for too long, pump flow pulsation occurs thereby leading to vibration of the pump. Of all the major causes of pulsation, the lack of proper feed is a major one. Other causes of pulsation could include leaking valves, worn packing, improper spring rates, piping designs that restrict flow, and multiple pumps on a common header. A suction stabilizer to keep the contact of the fluid with the plunger is one of the best ways to prevent pulsation.
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