A centrifugal pump tripping (shutting off unexpectedly) can result from electrical, mechanical, or operational issues. Below are common causes and troubleshooting steps.
Symptoms:
Pump trips after running for some time.
Motor feels excessively hot.
Possible Causes:
✔ Overloading – Pump operating beyond BEP (Best Efficiency Point).
✔ High current – Voltage imbalance, wrong motor sizing.
✔ Faulty starter/contactor – Poor connections, damaged relays.
Solutions:
Check motor nameplate current vs. actual draw (use a clamp meter).
Verify voltage supply (should be within ±10% of rated).
Ensure correct thermal relay settings (adjust if needed).
Symptoms:
Immediate trip when starting.
Burning smell or sparks.
Possible Causes:
✔ Damaged cable/winding insulation.
✔ Water ingress in motor terminal box.
Solutions:
Perform megger test (insulation resistance check).
Inspect motor terminals & wiring for damage.
Symptoms:
Loud grinding noise.
Excessive vibration.
Possible Causes:
✔ Lubrication failure (grease dried out or contaminated).
✔ Misalignment (coupling or shaft).
Solutions:
Check bearing temperature (infrared thermometer).
Re-grease or replace bearings.
Symptoms:
Fluid leakage from seal area.
Pump loses prime.
Possible Causes:
✔ Dry running (no liquid in pump).
✔ Abrasive particles damaging seals.
Solutions:
Check mechanical seal for wear.
Ensure proper liquid supply (avoid dry running).
Symptoms:
Loud "rattling" noise.
Reduced flow/pressure.
Possible Causes:
✔ Low NPSHₐ (Net Positive Suction Head Available).
✔ Clogged suction strainer.
Solutions:
Increase suction pressure (raise tank level).
Clean strainer/filter.
Symptoms:
Pump runs but delivers no/low flow.
High motor current.
Possible Causes:
✔ Debris stuck in impeller.
✔ Closed/discharged valve.
Solutions:
Inspect impeller for clogging.
Verify discharge valve is fully open.
Symptoms:
Pump trips when throttling.
Pressure spikes.
Possible Causes:
✔ Closed valve in discharge line.
✔ Wrong pump selection (oversized/undersized).
Solutions:
Check system curve vs. pump curve.
Ensure valves are properly adjusted.
Symptoms:
Pump runs but no discharge.
Gurgling noise.
Possible Causes:
✔ Suction line not fully primed.
✔ Air leaks in suction piping.
Solutions:
Bleed air from pump casing.
Check for suction line leaks.
Did the pump trip immediately on start?
Yes → Check electrical (short circuit, overload).
No → Proceed.
Is the motor overheating?
Yes → Check load, voltage, cooling.
No → Check mechanical (bearings, seals).
Is there abnormal noise/vibration?
Yes → Inspect impeller, alignment, cavitation.
No → Check system resistance & valves.
✔ Regular maintenance (lubrication, alignment checks).
✔ Install protection devices (overload relay, flow switch).
✔ Monitor pump performance (current, pressure, vibration).
Need help diagnosing a specific tripping issue? Provide details (when it trips, noise, error codes), and I can assist further!
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