1. Installation conditions
When the installation orientation is specified or the performance of the thermal protector is affected by the installation conditions, the installation conditions shall be clearly specified in the product documentation or the installation conditions shall be determined in agreement with the motor manufacturer.
2. Structural requirements
2.1 The structural requirements of the leads and / or terminals.
2.1.1 The structure of the lead-out wires and / or terminals should ensure good electrical contact and corresponding current-carrying capacity.
2.1.2 The lead-out wires and / or terminals should be easy to connect with external conductors.
2.1.3 The connection of the lead wire and / or the terminal and the external wire can be achieved with screws or other effective measures, but it should be ensured that the contact pressure is constant or changes little.
2.1.4 The lead-out wires and / or terminals should be able to withstand 50N axial and / or lateral static tensile force for 1 min.
2.1.5 The thermal protector should have good insulation ability to the outside.
2.2 The adjustment mechanism for temperature setting should be equipped with an effective stop device to ensure that no looseness occurs during use.
2.3 The manual reset mechanism should be able to operate reliably under normal working conditions.
2.4 Under normal working conditions, the manual reset mechanism shall not reset itself after the contacts are broken without manual reset operation.
3. Material requirements
3.1 Live parts shall be made of corrosion-resistant or corrosion-resistant metal.
3.2 The insulating material should be able to withstand the test temperature test of the top of the glow wire at 850 ℃ ± 10 ℃ for a duration of 30s ± 1s.
3.3 Metal parts shall not have cracks and the coating shall fall off, and plastic parts shall not have bubbles, cracks, no obvious marks and scratches.
4. Performance requirements
4.1 Rated breaking temperature
The rated cut-off temperature ranges from 70 ° C to 160 ° C every 5 ° C. The tolerance of the rated cut-off temperature is ± 5 ° C, ± 8 ° C, ± 10 ° C.
4.2 Reset temperature
4.2.1 The reset temperature of the automatic reset type thermal protector is lower than the rated breaking temperature by more than 10K, and its tolerance is ± 15 ℃.
4.2.2 The manual reset thermal protector should not be automatically reset in an environment higher than -5 ℃.
Note: The manufacturer can set other rated operating temperature and reset temperature and tolerance according to user requirements.
4.3 Rated tripping current
The manufacturer of the thermal protector shall provide the rated trip current, nominal time and tolerance of the nominal time of the thermal protector at the specified ambient temperature in the form of a chart or curve.
4.4 Critical trip current
The manufacturer of the thermal protector shall provide the characteristic data of the critical trip current of the thermal protector against the ambient temperature in the form of a graph or a curve.
4.5 Contact resistance
When the contacts are closed, the contact resistance between the terminals should not be greater than 50mΩ.
4.6 Insulation resistance
a) In the state of thermal break of the contact, the insulation resistance between the two lead wires or terminals should not be less than 2MΩ;
b) The insulation resistance of the lead-out wire or terminal and the surface of the insulation layer of the housing should not be less than 5MΩ.
4.7 Electrical strength
Apply a basic sine wave with a frequency of 50 Hz to the thermal protector between the following locations. The test voltage (effective value) should be free of flashover and breakdown for 1 min.
a) In the state of thermal break of the contact, the electrical strength between the two lead wires
b) In the normally closed state of the contact, the electrical strength between the lead wire and the insulation
4.8 Durability
4.8.1 Under the conditions of AC 50Hz, product rated voltage and power factor cosΦ of 0.75 ~ 0.8, the automatic reset thermal protector shall meet the following after passing the rated current test 2000 times
a) The change in operating temperature does not exceed ± 5% or ± 5 ° C of the initial value, whichever is greater.
b) No welding occurs on the contacts.
After continuing the test for 4000 times, the thermal protector has no permanent damage to the operating performance
