FAQs

The differential or hysteresis is the difference in temperature, measured in degrees Celsius, between the point where the thermostat first operates and the level where the contacts return to their original state.

Yes, in some cases a specific differential range can be supplied through a selection process however a minimum differential of 10°C must be maintained in order to insure a strong snap of the bimetal disc. Limitations do exist in the results obtainable as we can only select thermostats from within the actual range of temperatures [...]

The snap action thermostat is the result of the design of the bimetallic disc which is formed in order to hold its original shape until the specified transition temperature and then switches the position of the contacts quickly. Also a differential or hysteresis is built into the design which eliminates the rapid and repeated on/off [...]

Each Cantherm/Microtherm product is tested before leaving our factory. Depending on the particular model switch that you have purchased, they have either been tested for response temperature on a sample batch basis based on AQL 2.5 level I, or tested on a 100% basis. The pill type thermal protectors (F, B, T) are tested 100% [...]

Often the perceived operating temperature of a thermostat in the actual application will differ from the published temperature range because of thermal lag. This is the result of the thermal mass of the device and the thermal resistance of the insulation which slows down the reaction of the bimetal disc. The bimetal disc always operates [...]

In order to standardize results and to be able to compare one thermal switch to another, the industry has adopted a standard rate of temperature change which ranges from 0.25°C to 1.0°C change per minute. The larger and the more thermally resistive the package the slower the temperature rise rate must be. After the rise [...]

A creeper thermostat is generally manufactured with a blade type bimetal which has not been pre-formed as is a disc type. Calibration is achieved by either bending the bimetal or adjusting the pressure of the contacts until the desired result is achieved. Essentially a creeper has almost no differential and once the operating temperature has [...]

A PTCR thermal protector has a tiny PTC (positive temperature coefficient) ceramic heater imbedded into its body, it is connected in parallel with the contacts of the switch and as long as the switch is closed it does not heat. When the contacts of the protector open due to an external heat source the PTC [...]

A thermal fuse is a single operation device similar to a current limiting fuse which is sensitive to surrounding temperatures instead of the current passing through it. The small low current type are made using a fusible link material whereas the higher capacity fuses are equipped with an organic or wax pellet which hold the [...]

A thermal protector is a device which has been designed to protect an apparatus or appliance against an excessively high temperature. They are typically used in electric motors, transformers and heaters to prevent overheating but can be installed in any type of equipment that is sensitive to high temperatures or to prevent damage, fire or [...]