Fan motors, bearings and electronic controllers generate heat during continuous operation. A blocked blade, increased bearing resistance or locked rotor can rapidly increase current and temperature. A dedicated test system combines multi-channel temperature measurement, electrical acquisition and controlled abnormal-operation fixtures.
1. Test Functions
- Temperature rise at different fan speeds;
- Motor housing, winding, bearing and controller temperatures;
- Current and power during locked-rotor conditions;
- Thermal protector or electronic protection operating time;
- Recovery behavior after protection.
2. Temperature Acquisition
Thermocouples or PT100 channels can record key points together with ambient temperature. Sensors must be secured without changing the cooling path. Long-duration tests can store data at one-second or configurable intervals to generate temperature-time curves.
3. Locked-Rotor Fixture
The fixture must prevent rotation safely without creating unrelated damage. Adjustable stops or dedicated shaft-locking fixtures may be used. Remote operation and protective guarding are essential because the fan remains energized during the abnormal condition.
4. Procedure
- Record rated motor and protection information;
- Install and verify temperature sensors;
- Run the fan to thermal stability;
- Create the specified abnormal condition;
- Record current, power, temperature and protection time;
- Automatically disconnect power at the stop condition;
- Allow cooling and verify recovery;
- Inspect motor, wiring, controller and enclosure.
5. Safety and Data Analysis
Independent overcurrent, overtemperature, smoke detection and emergency power removal should supplement software limits. Excessive normal temperature may indicate poor efficiency or cooling. Delayed protection during locked rotor requires review of protector rating and thermal coupling.
6. Laboratory Integration
The test bench can be integrated with power analyzers, environmental acquisition and video monitoring. Final abnormal-operation conditions and acceptance criteria should follow the applicable product standard.