1. Application Background

Different fans are often used in different industries, generally including external rotor fans, centrifugal fans, etc. For example, they are used in high-speed tunnels, factory workshops, cars, 5G communication base stations, etc. Different application environments have different effects on fans and different working conditions required for fans; when the ambient temperature is too high or the fan is abnormally hot, it is easy to burn the motor and cause fire hazards. If the fan has a built-in thermal protector, similar situations can be effectively avoided to ensure safety.

2. Protection Principle

When the fan is abnormally overheated or the ambient temperature is too high, the temperature sensed by the protector reaches the rated action temperature, the bimetallic strip of the protector will deform, separate from the contact, form a circuit, and actively cut off the power supply. If the protector is in the control loop, it will transmit a signal to the motor control board to cut off the power supply. When the temperature returns to normal, the protector is reset and the fan works normally.

3. Installation Location

• Buried in the coil and connected to the main circuit, the temperature sensing is more accurate and sensitive, and the power supply can be cut off directly.

• Stick the protector on the surface of the coil, and then wrap it with insulating tape to fix it.

4. Selection

• Volume: To facilitate embedding inside the coil, you can choose round ST01 and ST06 series. If you stick it on the surface of the coil, you can choose ST07, BW-B, etc.

• Current: According to the fan stall and rated current, choose ST01 (6.3A) or ST06 (10A) or STH6 (13.5A), etc.

• Temperature: Generally 130℃, 150℃, 155℃... and 180℃; most insulation grades are F grade, and those with higher requirements will have H grade.

• Contact switch form: Generally normally open or normally closed, there is also a manual reset type, which can only be reset after power failure and troubleshooting to ensure the safety of maintenance personnel.