What to Pay Attention to for Motor Heat Dissipation Before High Temperatures

As mid-May arrives, temperatures are rising rapidly across the country. For manufacturing factories, high temperatures pose challenges not only to employees but also to every electric motor in the workshop.

Motor overheating can, in mild cases, accelerate insulation aging and shorten service life; in severe cases, it can directly burn out windings and cause unplanned production downtime. In fact, most motor failures can be avoided through systematic heat dissipation inspections before the arrival of summer. Today, let’s talk about what and how to inspect motor heat dissipation ahead of the high-temperature season.

I. Why Electric Motors Are Prone to “Heatstroke” in Summer

Electric motors generate heat during operation from copper loss, iron loss, mechanical loss and other energy losses. Under normal conditions, this heat is dissipated through cooling fans, heat dissipation fins, the motor shell and ambient air convection. However, summer brings drastic changes:
The ambient temperature surges from 20°C to 35°C or even higher, greatly reducing the air’s heat dissipation capacity. Poor workshop ventilation or densely arranged motors leads to localized heat accumulation. Running at full load or even overload further increases heat generation.

Consequently, the internal motor temperature exceeds the limit permitted by the insulation class, causing rapid aging of winding insulation. For every 10°C rise in temperature, the insulation service life may be halved. Therefore, conducting a systematic heat dissipation inspection before the peak heatwave is far more cost-effective than repairing breakdowns after they occur.

II. Pre-Summer Motor Heat Dissipation Inspection Checklist

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This checklist covers five key dimensions: ambient ventilation, motor body cooling components, air cooling system, lubrication and load. Maintenance personnel are advised to conduct item-by-item troubleshooting.

✅ 1. Ambient Ventilation: The Core of Motor Heat Dissipation

Surrounding space: Sufficient heat dissipation clearance shall be reserved around the motor with no blockage at the air inlet. Common issues include piled materials, oil contamination coverage and debris placed close to the motor.Solution: Clear all debris within 1 meter of the motor to restore natural air convection.
Workshop overall ventilation: Smooth air circulation with no trapped hot air is required. Common problems include enclosed workshops, faulty exhaust fans and clogged air inlet filters.Solution: Overhaul the exhaust system and deploy forced ventilation during high-temperature periods.
Spacing between multiple motors: The distance between adjacent motors shall be no less than 1.5 times the motor width. A common fault is side-by-side close installation causing heat accumulation.Solution: Adjust layout or install partition air ducts.

✅ 2. Motor Cooling Components: Fans, Fan Shrouds & Heat Dissipation Fins

External cooling fan (if equipped): Operate normally with sufficient air volume. Common faults include broken fan blades, fan failure or reverse rotation (reversed airflow).Solution: Manually test rotation, confirm correct rotating direction, and replace damaged blades.
Integrated coaxial fan: Unobstructed fan shroud and smooth airflow path are mandatory. The mesh of fan shrouds is often blocked by cotton lint and dust.

Solution: Blow clean from the inside out with compressed air; do not rinse with water.
Heat dissipation fins: Keep fin gaps free of dust for unobstructed airflow. Oil sludge mixed with dust often forms an insulating layer on fins.Solution: Clean with a soft brush or low-pressure air gun to keep fins spotless.

Practical Tip: Place your hand at the fan shroud air outlet to feel the airflow. A normal motor should produce obvious wind flow. If there is barely any airflow, first check for fan reverse rotation (caused by incorrect wiring of three-phase motors), then inspect for blocked air paths.

✅ 3. Lubrication & Bearings: The Hidden Trigger of Overheating

Bearing failure is an invisible leading cause of motor temperature rise. Poor lubrication or worn bearings generate excessive friction heat, which quickly transfers to motor windings.

rease refilling cycle: Refill grease regularly based on operating hours (generally every 2,000 to 4,000 hours). Common mistakes include never refilling grease or over-lubrication, which worsens heat dissipation.
Grease model: Use the grade specified by the motor manufacturer. Mixing greases with different base oils will cause thickening and decomposition.
Bearing temperature: Normal operating temperature shall not exceed 95°C (subject to insulation class). Pay close attention to abnormal temperature rises without timely inspection.

Key Reminder: Before summer, replace or replenish lubricating grease for motors that have run for more than half a year. Aged grease loses its lubrication and heat dissipation performance.

✅ 4. Electrical System & Load: Reduce Heat at the Source

Excessive current is a major root cause of motor overheating. Even optimal heat dissipation cannot offset heat generated by faulty load conditions.

Operating current: Measure three-phase current with a clamp meter. Warning standard: Current shall not exceed the rated value, and three-phase current unbalance shall be less than 5%.
Voltage: Measure terminal voltage of the motor. Warning standard: Voltage fluctuation shall be within ±10% of the rated voltage.
Inverter parameters: Check carrier frequency and overload protection settings. Warning standard: Excessively high carrier frequency causes extra motor heat; keep the manufacturer’s default setting in most cases.

✅ 5. Targeted Solutions for Motors in Special Environments

Dust-prone workshops (cement, polishing, woodworking): Motor heat dissipation fins are easily clogged with dust. Blow clean weekly or adopt a forced air cooling structure with dustproof filters.
Humid & corrosive workshops (electroplating, chemical industry): Corrosion may peel off the shell heat dissipation coating and weaken radiative heat dissipation. Meanwhile, check terminal box sealing to prevent moisture ingress and insulation resistance decline.
Areas near high-temperature kilns: Ambient temperature may exceed 50°C. Ordinary motors need additional heat shields or compressed air auxiliary cooling.

Quick Compliance Checkpoints

No debris or material accumulation within 1 meter of the motor
Fan shroud mesh free of cotton lint and dust blockage
Clean heat dissipation fin gaps with no oil sludge caking
Correct rotation direction and sufficient airflow for external fans
Lubricating grease refilled on schedule with correct model
Operating current within rated value with balanced three-phase power
Inverter carrier frequency set to a reasonable level
Hand can stay on running motor surface for more than 5 seconds
Workshop exhaust fans and air inlets in normal working condition

If more than 2 items fail to meet standards, arrange professional maintenance as soon as possible.

III. Action Recommendations Before the High-Temperature Season

Arrange a special motor heat dissipation inspection immediatelyDo not wait for overheating alarms or tripping downtime. Complete all inspections in May to ensure stable operation from June to September.
Establish an emergency mechanism for hot weatherIncrease inspection frequency on days with temperatures ≥35°C, and measure motor surface temperature daily. Prepare spare cooling fans, lubricating grease and other consumable parts in advance. Install temperature stickers or wireless temperature measuring devices for critical process motors.
Complete energy-saving and cooling renovation before June if conditions permitReplace old inefficient motors with IE4 high-efficiency motors that generate less heat; or install independent axial flow fans for high-power motors to assist heat dissipation.

Motors cannot speak, but their operating temperature reveals their operating condition.

As summer arrives, equipment prevention is always better than emergency repairs. A burned-out motor means not only equipment replacement costs but also cascading losses such as full production line shutdown, order delays and contract breach penalties.

Motors are designed to withstand high ambient temperatures, yet they are not immune to extreme heat. One more routine inspection, one more cleaning and one more standardized maintenance in daily operation mean fewer failures, less downtime and lower losses in hot summer.

Make adequate cooling and protection preparations for motors ahead of summer. Stabilizing equipment operation is equivalent to safeguarding factory production efficiency and profits!

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