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The most direct sign of a cooling system issue is an abnormal rise in motor temperature. Symptoms may include:
The motor housing or bearing areas feel unusually hot to the back of the hand (exercise caution) – well above normal operating temperature.
Temperature readings on the control panel or via remote monitoring systems remain persistently high, possibly triggering an over‑temperature alarm.
For water‑cooled motors, the cooling water outlet temperature may be significantly higher than normal.
In severe cases, the motor may shut down automatically due to thermal overload protection.
If any of these signs appear, immediate troubleshooting of the cooling system is required.
Follow a logical sequence – from external to internal, from simple to complex.
Start with visual, auditory, and tactile checks:
Visual: Check the motor surroundings – ensure that air inlets and outlets are not blocked by debris or foreign objects. For water‑cooled units, look for obvious water leaks or seepage at the cooling water inlet/outlet pipes.
Auditory: Listen for unusual noises from the cooling fan, such as scraping or vibration, which could indicate bearing damage or impeller rub.
Tactile: When safe, touch the inlet and outlet water pipes to feel the temperature difference. A very small temperature difference suggests poor heat exchange efficiency.
This is a key focus area:
For water‑cooled systems (cooling water):
Flow and pressure: Confirm that the cooling water pump is running normally, and that the readings on the pressure gauge and flow meter are within normal ranges. Low pressure may indicate pump failure or pipe leakage.
Water quality: Check whether the cooling water is turbid, contains impurities, or has deteriorated. Using hard or unfiltered water over a long period can lead to scaling and pipe clogging.
For air‑cooled / forced‑air systems (cooling fan):
Operating status: Verify that the fan motor is energised and running; check power supply and fuses.
Rotation direction: This is critical. The fan must rotate in the correct direction to generate sufficient air pressure. Check the rotation arrow on the fan and confirm it matches. Reverse rotation is a common cause of poor heat dissipation.
If the above checks are normal, the problem may lie inside the cooler or piping:
Blockage inspection:
Air‑cooled radiators: Check whether the air passages are severely blocked by dust, oil, or foreign objects.
Water‑cooled heat exchangers: Inspect the internal tubes for scaling or blockage. Scale build‑up drastically reduces heat transfer efficiency.
Leak inspection:
Water‑cooled systems: Focus on tube‑to‑tubeplate joints, pipe joints, and welds of the cooler. For suspected tiny leaks, use a leak detector for confirmation. Leaks in an air‑to‑water cooler are especially dangerous as water may enter the motor and cause insulation damage.
Material and corrosion inspection (water‑cooled systems):
Check for severe corrosion, oxidation, or rust on pipes and the cooler. Special attention should be paid to joints between dissimilar metals (e.g., steel and aluminium) where galvanic corrosion may occur.
Based on the identified issues, apply the corresponding fixes:
| Fault Type | Specific Remedial Actions |
|---|---|
| Cooling medium problems | Poor quality / blockage: Clean or replace the cooling water; install filtration equipment; use tools like nylon brushes to remove scale and debris from cooler tubes. Contamination by lubricants: Identify and replace any lubricants that have mixed into the cooling system, preventing them from accumulating in the condenser. |
| Pipe / cooler leakage | Damaged piping: Repair or replace the affected pipe sections. Joint / weld leaks: Apply methods such as staking, plugging, or sealing. For aluminium pipes, apply specialised adhesives to seal and prevent oxidation at leak points. |
| Fan / pump failure | Incorrect fan rotation: Immediately stop the motor and swap two phase leads to correct the direction. Fan / pump damage: Repair or replace the faulty fan motor, water pump, or associated bearings. |
| Low cooler efficiency | Scaling / dust build‑up: Perform thorough cleaning of the heat exchanger on a regular basis; water‑cooled systems require specific descaling procedures. Design mismatch: If calculations confirm the existing cooler capacity is insufficient, consider upgrading to a larger heat exchanger or increasing the heat‑transfer area. |
| Temperature control system faults | Sensor failure: Calibrate or replace ageing temperature sensors to ensure accurate monitoring. Controller issues: Inspect and optimise control parameters of the temperature control system to ensure it responds flexibly to temperature changes. |
Regular maintenance is key to avoiding sudden cooling system failures:
Routine inspections: Establish a daily inspection schedule – listen for abnormal fan noise/vibration, and monitor water pressure, flow, and temperature readings.
Periodic servicing: Plan regular maintenance – clean air ducts and radiator fins of dust and oil, flush the cooler, and check all fasteners.
Water quality management: For water‑cooled systems, always use treated soft water or deionised water, and test water quality periodically to prevent scaling and corrosion.
Spare parts inventory: Keep essential spare parts (e.g., cooling water pumps, fan motors) on hand so that quick replacements can be made during failures, reducing downtime.
