Bulgconstante: Introduction to the points of attention for installing jump temperature controller

Jump type temperature controller is a bimetallic sheet temperature controller with shell, common such as KSD301,KSD302, etc., the temperature controller is a new product of bimetallic sheet temperature controller, mainly used as a variety of electric heating products with overheating protection, usually connected with the thermal fuse, jump type temperature controller as a primary protection. The thermal fuse is used as the secondary protection when the thermal element overtemperature is caused by the loss or failure of the jump temperature controller. The combination of the two can effectively prevent the burning out of the thermal element and the fire accident caused by it. The application range is very wide.

1. When installing the jump temperature controller, it is absolutely not allowed to make the temperature sensing surface (cover) deformation, not to collapse or make the top of the cover deformation, so as not to affect the temperature and electrical performance of the temperature controller;

2. When installing a jump temperature controller, do not bend the wiring terminals of the temperature controller and ensure that the terminals are in good contact with each other. Otherwise, electrical contact reliability may be affected. If the soldering wire is used, the soldering iron of no more than 60W should be selected, and the soldering time should be controlled within 5 seconds.

3. When the jump type temperature controller is installed, the temperature sensing surface of the temperature controller cover should contact the temperature control part evenly; When the temperature controller adopts contact temperature sensing, it is better to coat the cover temperature sensing surface with a layer of thermal conductive silicone grease, so that there is no gap between the temperature sensing surface and the temperature control surface, so as to improve the thermal conductivity effect.

4. The use environment of the jump temperature controller should avoid stains and dampness, otherwise the electrical performance of the product will be affected. The temperature controller must be used in the working environment where the relative humidity is less than 90% and no corrosive and combustible media contact. For use in humid environments or immersed liquids, the thermostat needs a special impermeable seal.

For superheat protection devices, how to assemble the circuit board has always been a tricky problem, because the high temperature of the SMD process during the assembly process will cause the thermal protection devices "painful" early disconnection, manufacturers are using manual assembly to avoid this problem, but it also increases the cost. Tyco Electronics recently introduced a mysterious weapon to solve this contradiction, making the heat protectors withstand the high temperatures of reflow welding, ending the history of heat protectors that cannot be assembled using the SMD process.

This mysterious weapon is the Reflowable Thermal Protection (RPT), which can withstand reflowable thermal protection for three times at peak temperatures well above 200℃(up to 260℃) without being turned on. However, when it is used in practice, it will be disconnected once the temperature is detected above 200℃. How does this pair of seemingly contradictory metrics work?

It turns out that this RPT uses a one-time electron activation mechanism. After the reflow is completed, the RPT can be activated during the final test. When the RPT is activated, it becomes heat sensitive and opens an open circuit when its temperature reaches 200℃. This disconnect is not automatic, once the RPT is disconnected, you can only reinstall one. This active time node is very flexible to the user and can be implemented automatically during system startup or system testing.

The first component in the electronic RPT product family, the RTP200, can be used to replace redundant components such as power field effectors, relays and heavy-duty radiators that are often used in automotive designs to save on cost and space, according to the report. Compared to traditional thermal protection solutions such as TCD, PPTC and resistors, it has the overall advantages of low thermal disconnection, high reliability, suitable for SMD assembly, high DC working current (over 30A), maximum interrupt current over 100A, and one-time disconnection. Even now the hot PPTC can not do one-time disconnect, high working current and such a large disconnect current, not to mention it is not resistant to high temperature, at 175℃ on the disconnect.

However, the disconnect temperature of the 200℃ RTP200 is a little strange, many automotive operating temperature chip working range is far less than 200℃, RTP needs to detect the device temperature around 200℃ before disconnect, will lose the protective effect? Eric Braddom, global marketing strategy director for Tyco's Electronic Circuit protection division, explained that 200℃ is a suitable temperature disconnect point. This temperature is above the normal operating temperature range of most electronic components, but below the common melting point of lead-free solder. That is to say, the RTP200 device will not disconnect the circuit when the device next to it is working within the specified temperature range; However, after the temperature exceeds the normal range, the circuit will be disconnected before the device unwelds and creates a risk of short circuit.