Interruptor térmico bimetálico : tipos & aplicaciones

¿Qué son los interruptores térmicos bimetálicos??
Uso de interruptores térmicos bimetálicos Una tira bimetálica es una tira que consta de dos tiras de diferentes metales que se expanden a diferentes velocidades a medida que se calientan.. Se utilizan para convertir un cambio de temperatura en desplazamiento mecánico.. crea un arco redondo, como un arcoiris. A medida que cambia la temperatura, Los metales continúan reaccionando de manera diferente., funcionamiento de los interruptores de corte térmico.

Bimetal thermal switchs are widely used inside heating pads, blankets, medical pads, hervidores eléctricos, and in some other devices where the application demands a cheap temperature controller mechanism.

Inside most home electrical appliances, we can generally find bimetal thermal switchs (temperature Snap Action switches) in two varieties – high voltage (Hi Amp) thermal switchs which directly control the flow of electric current to the load, or low voltage thermal switchs which indirectly control the current flow to the load. Schematic symbols for the common bimetal thermal switchs are shown below.

High voltage (Hi Amp) thermal switchs are rated for the voltage, current and power ratings of the loads they can handle safely. Por ejemplo, a thermal switchs rated at 250V and 10A can be used to control a 2500W(max) load.

Low voltage (and Low Amp) thermal switchs are comparatively smaller and cheaper, but they are more sensitive to changes in heat than high voltage thermal switchs. That means since they are only intended to handle the control current and not the load current, low voltage thermal switchs are highly responsive and can provide more precise control than their high voltage counterparts.

A bimetal thermal switchs opens or closes an electric connection at a predefined temperature. Here is the inside view of a bimetal thermal switchs lifted from an old coffee maker machine. See how everything is put together!

The online customized thermal switch factory in China provides the following complete bimetallic thermal switch parameters and selection:

The first is a 10A~60A/250V resistive load disc bimetal thermostat switch from the KSD301 /KSD302 series. operating temperatures ranging from -40°C to 280°C. Some of them have normally-open contacts, while others have normally-closed contacts.

KSD301 series bimetal thermostat thermal switch

Normally closed KSD301 thermal switch

Hi-Amp – High voltage KSD302 bimetal thermal switch

Next is the TO-220 PCB-bimetal disc thermal switch from the JUC-31F series (PCB-bimetal thermal switch ). Currently, JUC-31F 95°C H This is the most common PCB mounted thermal switch with normally-open (close on rise) contacts.

ksd-01F/JUC-31F 0°C~130°C PCB mounting thermal switch

KSD-9700 most common and the cheap series thermal switch. consists of dish shape high sensitive bimetallic elemeng,movable contact-head,static contact-piece,soleplate,outer case,ghermal resistant lead and so on. When operation,the bimetallic element is in free state and movable contact-head and static contace-piece are closed and the circuit is on. normally-closed KSD 9700-A 250V 5A 70°C thermal protectors ( KSD-9700.pdf).

Interruptor térmico bimetálico KSD9700 barato de corte de alta temperatura

Personaliza los parámetros y cables del protector térmico 17AM-D+PTC, y también procese el mazo de cables para agregar un fusible térmico. 17Protector térmico AM-D+PTC (Texas Instruments KLIXON) es sensible a la corriente, Dispositivo de protección con detección de temperatura conectado en serie con la bobina del motor.. El protector cambia dependiendo de la temperatura de la bobina y la corriente del motor..

17SOY + PTC overheating and overcurrent bimetal thermal switch

Knowledge of bimetallic strips:
A bimetal switch changes its switching status relative to the temperature. If the temperature is sufficient, the bimetall bends, thereby actuating a snap-action switch. This switch can open or close a circuit and in so doing start or stop a process (e.g. heating, cooling, pumping).

A bimetallic strip or bimetal strip is a strip that consists of two strips of different metals which expand at different rates as they are heated. Se utilizan para convertir un cambio de temperatura en desplazamiento mecánico.. The different expansions force the flat strip to bend one way if heated, and in the opposite direction if cooled below its initial temperature. The metal with the higher coefficient of thermal expansion is on the outer side of the curve when the strip is heated and on the inner side when cooled.

Bimetallic switches are used as part of the control engineering in the electrical industry, especially in auto-temperature control and temperature -indicating devices and appliances like heating, cooling, and pumping. Bimetallic thermal switches work on the principle that different metals bend at different temperatures. When the set temperature is achieved, one of the metals in the bimetallic switch bends to cut off the circuit and protect the appliance from extreme temperatures.

The TB02 series protector is a thermal switch with small dimensions（Referred to as battery pack thermal protector）, insulating case, high temperature sensitivity and long lifetime, which is widely used in lithium batteries, iluminación, transformadores, aparatos de calefacción eléctrica, and other fields.

Interruptores térmicos de batería de tamaño más pequeño TB02

Características:
Snap action type bimetallic disc has the characteristics of high reliability and repeatability.
Small dimension is suitable for appliances which compactly installed upon winding or inside winding.
Steel structure bracket makes performance more stable.
Automatic temperature calibration process makes it has a high precision of temperature control.
The bimetallic disc overflow structure solves the technical difficulty of current transient overload and the temperature response lag.

Custom specifications according to customers’ req thermal switch
A key advantage of this concept is that the thermal switch can be installed in any desired local/remote location as it demands nothing but a simple two-core low-voltage cable for the interconnection. The low-voltage control circuit can then be used to drive an appropriate electromagnetic relay module (or a solid state relay module) to safely deliver power to the isolated high-voltage load, a mighty heater wire for example.

Basically, the circuitry switches on and off at different thresholds, so there is no leaping between one state and the other as the capacitors charges. That worked very reliably, no tweaking of the basic setup required. I have used this on a few Various electrical appliances designs now, and they have always proven very reliable.