Thiết bị bảo vệ quá nhiệt là gì?

The overheat protector is an automatic control device that achieves equipment safety protection through temperature monitoring. Its core function is to cut off the circuit or trigger the protection mechanism when the temperature exceeds the set threshold to prevent the equipment from malfunctioning or causing fire due to overheating. The following are its technical details and application analysis:

Function and application of motor overheat protection device

Application case of automobile motor overheat protection device

Thiết bị bảo vệ nhiệt áp dụng cho pin

1. ‌Core Principle and Type‌
‌Bimetallic Strip Structure‌: Using two metal composite sheets with different thermal expansion coefficients, the deformation triggers the contact action when the temperature rises (normally open/normally closed type).
‌Self-recovery and non-self-recovery type‌:
Self-recovery type: automatically reset after the temperature drops (such as refrigerators, máy giặt);
Non-self-recovery type: manual reset is required (such as fuel motors, industrial equipment).
‌Thermistor linkage‌: Some models combine thermistors or single-chip microcomputers to achieve precise temperature control.

How it works:
Sensors:
Overheat protection devices typically utilize temperature sensors (like thermistors or bimetallic strips) to monitor the temperature of a specific area.
Threshold:
When the temperature exceeds a pre-set threshold, the sensor triggers a signal.
Action:
This signal then activates a circuit breaker, relay, or other mechanism that either disconnects the power supply or reduces the power output of the device.

2. ‌Key parameters and selection‌
‌Temperature range‌: Common action temperature 40-180℃ (such as KSD9700 series tolerance ±3/5℃);
‌Current/voltage‌: Typical specifications AC250V/5A, high-voltage models can reach AC1800V;
‌Structural form‌:
Plastic shell (PBT material, lightweight);
Metal/ceramic shell (high temperature resistant, insulation).

Thermal protector device for heating pad

Thermal protector device for medical treatment

Thermal protector device for instant water heater

3. ‌Typical application scenarios‌
‌Household appliances‌: air conditioner motors, máy giặt, vân vân., to prevent motor windings from overheating‌; ‌Industrial equipment‌: submersible pump stator coil temperature monitoring (such as GB-220V protector); ‌Electronic circuits‌: processor heat dissipation protection to avoid high temperature attack vulnerabilities‌. Examples of overheat protection devices:
Thermal protectors in motors:
These devices are embedded within electric motors to prevent overheating, which could cause the motor to fail or catch fire.
Cabin overheat protection in vehicles:
Some vehicles, like Tesla, have a cabin overheat protection feature that automatically activates the air conditioning to prevent the interior from getting dangerously hot when parked.

4. PTC thermostors in electronics:
These are used in a variety of applications to protect circuits from overheating by significantly increasing their resistance when a certain temperature is exceeded.
Temperature limiters in heating systems:
These devices, like the one described in the Heatsystems article, are used to prevent heating elements from getting too hot, which could damage the heating element or surrounding materials.
Importance of overheat protection:
Safety: Preventing fires, equipment damage, and potential injury from overheating.
Reliability: Ensuring the longevity and proper functioning of devices and systems.
Efficiency: In some cases, like in vehicles, overheat protection can help optimize energy usage.

5. ‌Common Problems and Precautions‌
‌Installation requirements‌: Need to be close to the surface of the controlled equipment to avoid deformation of the shell affecting performance‌;
‌Risk of false operation‌: Solder aging or mechanical damage may cause protection failure‌;
‌Difference from overload protection‌: Overheat protection is based on temperature threshold, while overload protection responds to current abnormality‌.

6. ‌Technology Development Trends‌
‌Integrated design‌: Such as the jump-type bimetallic protector combined with overcurrent/overheating dual functions‌;
‌High reliability improvement‌: Ceramic packaging and anti-interference circuits improve adaptability to industrial environments‌.