2. Mechanical friction increase: Vertical turbine pumps have a long vertical shaft, and if the shaft alignment is inaccurate (e.g., the pump shaft is not concentric with the motor shaft), or the guide bearing/wear ring is severely worn, it will cause increased mechanical friction and drive up motor current. Additionally, if the packing seal is too tight, it will also generate excessive friction on the shaft.
Solution: Shut down the pump to check the shaft alignment (use a dial indicator to measure the concentricity, requiring deviation ≤ 0.05mm); replace worn guide bearings or wear rings in time; adjust the packing seal tightness (allow 1-3 drops of liquid per minute to seep out, balancing sealing performance and friction).

3. Liquid medium issues: If the density or viscosity of the conveyed liquid is higher than the design parameters (e.g., conveying seawater instead of fresh water, or liquid with suspended solids), the hydraulic resistance of the impeller will increase, leading to higher motor power consumption and current.
Solution: Recheck the liquid properties; if the medium changes permanently, replace the impeller with a model designed for high-density/viscosity media (e.g., impellers with thicker blades); if there are suspended solids, install a suction filter with appropriate mesh size to prevent particle wear and load increase.

1. Suction-side problems: Due to the long suction pipeline of vertical turbine pumps (especially when installed in deep wells or tanks), if the suction inlet is blocked by sediment or the pipeline has air leakage, it will cause uneven liquid intake, leading to "vortex vibration" and a "gurgling" noise.
Solution: Clean the suction inlet and filter (for well-installed pumps, regularly remove sediment at the bottom of the well); check the suction pipeline joints and gaskets for air leakage (apply soapy water to the joints—bubbles indicate leakage, requiring gasket replacement or re-tightening).

2. Shaft system instability: The vertical shaft of the pump is supported by multiple guide bearings. If the bearings are worn or the shaft is bent (due to long-term overload or improper installation), the shaft will swing during rotation, causing vibration (usually with a frequency consistent with the pump speed) and a "squeaking" friction noise.
Solution: Disassemble the pump to inspect the vertical shaft (use a straightness tester to check—bending tolerance ≤ 0.1mm/m); replace worn guide bearings (preferably use oil-lubricated bearings for high-speed pumps to reduce friction); if the shaft is bent, straighten it or replace it with a new one.

3. Hydraulic imbalance: If the impeller is worn (e.g., blade edge erosion) or the guide vane is blocked by scale, the liquid flow in the pump will be uneven, leading to "hydraulic pulsation"—manifested as low-frequency vibration and a "rumbling" noise.
Solution: Inspect the impeller for wear or damage (if the blade thickness is reduced by more than 10%, replace the impeller); clean the guide vane and flow channel (use a high-pressure water gun to remove scale or deposits, ensuring smooth liquid flow).

1. Key maintenance points:
(1) Shaft system and bearings: Check the guide bearings (submerged or oil-lubricated) for wear—measure the internal clearance (should not exceed 0.2mm for small pumps, 0.3mm for large pumps); add lubricating oil/grease (use 32# turbine oil for oil-lubricated bearings, lithium-based grease for grease-lubricated bearings) and replace the lubricant if it is emulsified or contaminated.
(2) Sealing system: For mechanical seals, check the seal face for scratches or leakage (if the leakage exceeds 5 drops per minute, replace the seal assembly); for packing seals, check the packing wear (replace if the packing is hardened or the leakage is excessive) and adjust the compression force.
· Impeller and wear parts: Inspect the impeller for erosion, cavitation, or blade damage (repair small cracks with welding, replace if damage is severe); check the wear ring (the gap between the impeller and wear ring should not exceed 1.5 times the original gap—replace if exceeded).
(3) Motor and coupling: Check the motor insulation resistance (should be ≥ 0.5MΩ for 380V motors); inspect the coupling for looseness or wear (tighten the coupling bolts if loose, replace the coupling if the rubber pad is damaged).

2. Reasonable maintenance cycle:
(1) Daily inspection (once per shift): Check motor current, pump vibration, noise, and seal leakage; record the inlet/outlet pressure and flow rate.
(2)  Monthly maintenance: Clean the suction filter; check the lubricant level and quality of guide bearings; tighten loose bolts (coupling, motor base, etc.).
(3) Quarterly maintenance: Disassemble the seal chamber to inspect the seal (mechanical seal or packing); measure the wear gap of the impeller and wear ring; check the vertical shaft straightness.
(4) Annual overhaul: Completely disassemble the pump to replace worn bearings, seals, and wear rings; inspect the motor stator/rotor for damage; perform performance testing (flow rate, head, power) after reassembly to ensure it meets design requirements.

(2) Inspect the motor wiring for looseness or phase loss (use a multimeter to measure the continuity of the three-phase windings—resistance should be balanced; if one phase is open, check the wiring or repair the motor).

A1: The installation of vertical turbine pumps (especially deep-well or submerged types) has high requirements for verticality and pipeline sealing. The key points are as follows:
1. Pre-installation preparation:
(1) Confirm the installation dimensions (check the pump's centerline, installation height of the motor base, and length of the vertical shaft—must match the well/tank depth; for deep-well pumps, the distance between the impeller and the well bottom should be 0.5-1m to avoid sediment suction).
(2) Inspect the pump components (check if the vertical shaft is bent, if the impeller and guide vane are damaged, and if the seal is intact—replace damaged parts in time).

2. Key installation steps:
(1) Ensure verticality: Use a level to adjust the motor base—verticality deviation of the pump shaft should be ≤ 0.1mm/m (for deep-well pumps, use a plumb line to check the verticality of the entire shaft system during installation; adjust the anchor bolts of the base if there is deviation).
(2)  Assemble the submerged components: For deep-well pumps, assemble the impeller, guide vane, and vertical shaft section by section in the well (ensure the shaft is concentric with the guide bearing; tighten the shaft coupling bolts evenly to prevent shaft misalignment).
(3) Seal the suction pipeline: For submerged pumps installed in tanks, the connection between the suction port and the tank bottom should be sealed with a rubber gasket (ensure no air leakage—air in the pipeline will cause cavitation); for deep-well pumps, the wellhead should be sealed to prevent debris from falling into the well.
(4)  Install the motor and coupling: Align the motor shaft with the pump shaft (use a dial indicator to measure the radial runout of the coupling—should be ≤ 0.05mm; axial runout ≤ 0.1mm); install the coupling elastic pad to reduce vibration transmission.

3. Post-installation inspection: 

After installation, manually rotate the motor fan blade—should be smooth without jamming; check the clearance between the impeller and the wear ring (should meet the design requirements); fill the pump with liquid (for self-priming vertical turbine pumps) to exhaust air in the pipeline.

2. Load test (connect the outlet pipeline and adjust the flow rate):
(1) Gradually open the outlet valve (adjust the opening degree in 10% increments) and record the corresponding flow rate, head, motor current, and power at each opening degree.
(2) Verify if the performance meets the design requirements: when the flow rate and head reach the rated values, the motor current should not exceed the rated current, and the power consumption should be within the design range (allow ±5% deviation).
(3) Test the stable operation at different working points: run the pump at 70%, 100%, and 120% of the rated flow rate for 30 minutes each. Check the pump's vibration, noise, and temperature (motor winding temperature ≤ 80°C, bearing temperature ≤ 70°C).

3. Cavitation test (for deep-well pumps): 

Reduce the suction height (or increase the liquid level in the well) gradually to simulate cavitation conditions. Record the critical cavitation margin (NPSH_c) of the pump—should be ≤ the available cavitation margin (NPSH_a) of the system (NPSH_a = NPSH_r + 0.3m, where NPSH_r is the required cavitation margin of the pump).

4. Commissioning acceptance: 

After the test, organize relevant personnel to review the commissioning data (flow rate, head, current, vibration, etc.). If all indicators meet the design requirements, issue a commissioning acceptance report; if there are deviations, adjust (e.g., replace the impeller if the head is insufficient, or adjust the valve if the current is too high) and re-test until qualified.