A:

The action temperature selection of a thermostat should be based on the application:
Measure the temperature of the position where the thermostat would be mounted;
Setting the temperature range of application;
Select the temperature of a thermostat. The current flowing through thermostat need to be considered when selecting this temperature. If this thermostat is used for heat protection, the action value should be above the normal working temperature, but lower than the temperature limit of other components to be damaged.

A:

Normally closed thermal switch means that the contacts of thermal switch normally remain closed. When temperature increases to the set value, the contacts would open and cut the circuit OFF.
Normally open thermal switch means that the contacts of thermal switch normally remain open. When temperature rises, the contacts would close and connect the circuit ON.
We now have several models that both Normally Open and Normally Close type are optional, like 17AME, TS01, KW, KSD301, 3MPE, and so on.

A:

According to the action type of contacts, the bimetal thermostat can be divided into creep action and snap action thermostat. General speaking, creep action thermostat can only be used for heating pad or cushion. Our WAA2 series thermostat belongs to creep action type.The function of creep action thermostat is for temperature adjustment, not for heating or over temperature protection. Only USA and Canada accept this kind of temperature controlling device. In Europe,creep action thermostat is not allowed to use. On the contrary, most of bimetal thermostats are snap action. The main purpose is over heat protection. Our KW model is snap action.

A:

It is a confusing question for some engineers. Actually, for current sensing thermal protectors, there are two current parameters. One is rated current. It is the nominal working current. The other one is tripping off current, also called over-loading current.
For the rated current, for examples, 3A or 5A, it means that the thermal protector can not trip off under this current. It would only cut the circuit off when temperature reaches the pre-set value.
But for the tripping off current, it means that the thermal protector has to trip off very quickly, like 4 to 10 seconds under this current. It is for overload protection purpose. General speaking, the tripping off current is around triple or 4 times of rated current. For example, if the rated current is 3A, the tripping off current should be set at 9A to 15A. It is only a rough estimation. The accurate value depends on the technical requirements of mock-up test and application.

A:

For some applications that have special demands for mounting space, the size of thermal switch would be extremely important. For example, battery pack, small motor and heating tube. They have no enough room to mount a thermal switch with bigger size. We now have two models with smallest size.
1. TS05, thickness 2mm only. It is now widely used for battery overheat protection and heating tube temperature control. This super thin thickness can make it insert into the batteries or heating tubes easily. The conductive leads can be wire or nickel strip.
2. S01 series. It is 8mm diameter and 2.6mm thick, even smaller than a cell battery. It is used for PCB mounting. TS01 with lead wire is used in small coil, transformer, heating tube or motor. The max temperature can be 200C.

A:

Customers like to ask the question:” Why does the smaller size thermal protector have higher price?” It sounds that it does not make sense. In fact, there are some reasons:
1. For the small size thermal protector, all parts have to be more precise. It means that we need to use better manufacturing machineries. The equipment cost would be higher.
2. The yield rate of smaller size thermal protector is lower than common size. So, the final cost would be higher.
3. The material of small size thermal protector is different also. The material has to be more reliable. Accordingly, the price of raw material is higher.
4. For the small size thermal protector, we have to use different machineries and manufacturing process. Both the manufacturing cost and labor cost are much higher than common size.
Due to the above reasons, the final cost of smaller size thermal protector is higher than common size.

A:

The lowest action temperature of our bimetal thermostat is 0C. It is creep action type and the relevant model number is 17AME-H. The contact making type can be normally closed or normally open. The main function of this thermostat is to remain the temperature inside of a narrow range. For example, OFF at 5C, ON at 3C or 4C. It is widely used to temperature control device or PCB control system. The life endurance can be 100,000 cycles also. The terminal ends of this bimetal thermostat can be at the same direction or opposite direction. The insulation paper has Nomex or Nitto for your option.
The shortage of this bimetal thermostat is the current. The max working current can’t exceed 5A, normally less than 3A. Since the current is too small, we sometimes to use gilded contact to avoid contacts oxidization.

A:

There are three reasons for thermal switch with lower temperature but higher price:
1. Thermal switches with lower temperature have to use some special materials, like bimetal strip and contacts. These materials have higher cost and better quality level;
2. In the process of manufacturing, both production and testing equipment for lower temperature thermal switches are different. The equipment cost of low temperature is higher than common temperature ratings.
3. The production yield of low temperature thermal switches is lower than standard temperature rating also. It would make the final cost is much higher.

A:

We can guarantee that our price is competitive based on the same quality level. The quality of bimetal thermostat cannot be distinguished by the picture or
appearance. To ensure the good quality consistence, we import the key raw materials like bimetal, insulation paper and contacts from USA, Japan and France.
The appearances of all these materials look same, but the quality level and price are totally different. Therefore, we believe that good quality product should have reasonable price.

A:

Yes. We are providing customized service for our noble customers. If you need a customized thermal protector sample, please kindly tell us the following parameters:
1) Rated voltage and Current
2) Action temperature
3) Dimensional requirements
4)Overloading or Tripping current if needed
5) Application and relevant special demands
6) Potential order quantity.
If the customized thermal protector has the same dimension as our current models, and you only need special parameters, we would not charge any cost for 5 pcs samples. If the requested dimensions are different, we may need to build new toolings for this customization. It would cause extra cost and we can negotiate separately.

A:

If you need to have temperature sensitive thermal protector samples, please prepare the following parameters:
1. Rated voltage, current
2. Action temperature of thermal protector
3. Leadwire length, type and temperature rating.
4. Application of thermal protector.
5. Mounting requirements if needed, including dimensional requirements.
If you want to have current sensitive thermal protector samples, you may prepare three more parameters besides the above:
1. Trip off current
2. Trio off time
3. Normally working temperature of thermal protector. It can not trip off under this temperature.

A:

1. If you need the contact resistance of thermal switch is less than 15 mOhm, you need gold contacts. The resistance of gold contacts is much smaller than silver contacts.
2. If the rated current of thermal switch is 250 mA or less, Gold contacts are necessary.  It can prevent oxidation of the contacts at low current rating. Oxidation forms an insulation film on the silver contacts and low current does not arc enough to burn off the oxidation.

A:

Incoming test for thermal switch includes temperature test under No-Load, mock-up test under load, functional test in applications and appearance inspection. Since mock-up test, functional test and appearance inspection can be easily done in the customers’ factories, we will only explain how to conduct temperature test under No-Load here.
1. Put the thermal switch inside of a test oven. The air flow speed of the oven needs to be over 200m/min
2. The measuring thermal couple should be as close to thermal switch as possible. An indicator of showing ON/OFF should be provided. The current flowing through thermal switch is less than 0.01A
3. Increasing the air temperature inside of the oven slowly. When air temperature increases to the 10C lower than the bottom tolerance limit of rated temperature value, the further temperature increasing speed has to be controlled at 0.5K/min.
4. When the temperature reaches the tolerance of thermal switch, the bimetal will actuate the contact and cut the circuit off. After that, the operator can open the cover of test oven and let the temperature decrease down. Then, the thermal switch will turn ON again.

A:

When the end users operate the appliances, the working current might exceed the rated value. If so, what would happen to the bimetallic thermal switch? There are some possible results:
1. The thermal switch would trip off earlier than the rated temperature. The reason is that the bigger current would generate more heat, and the bimetal would sense higher temperature than the rated value. So, it would trip off earlier.
2. The life endurance would be shorter. Bigger current would hurt both bimetal and contacts. There would be flashover between two contacts. If the current is too big, for example, 3 or 4 times of rated value, the two contacts would be stuck and could not open. That would make thermal switch malfunction, or even cause fire.
3. The thermal switch failed to action in few seconds and even burned the insulation sleeving
Therefore, it is very important for the user to operate the thermal switch correctly and try to avoid overloading the thermal switch.

A:

1. To ensure the quality consistence of our bimetal thermal switch, we got ISO9001:2008 version certification and fulfill the system strictly. In 2012, we started to implement TS16949 system to meet the demands of automotive cusotmers.
2. The life endurance we guaranteed is based on the working enviroment and rating. Different thermal switch has different level, like 10,000 cycles, 30,000 cycles or 100,000 cycles.
3. The defective rate of our thermal switch that we promise to our customer is 100 ppm.

A:

The warranty period of thermal protector we promised is not a specific time, like how many days, months or years, but the action cycles of thermal protector. Normally the life cycles ranges from 10,000 cycles to 100,000 cycles according to different models and working capacity. It is one of the most important parameters of thermal protectors. Customers can find it in the specification of different models.
The life cycles we mentioned here are only for working under rated current and voltage. If the working condition changed, the final life endurance would be also different.