PTC Heater Control Features

Characteristics of PTC heaters: Heaters made of PTC ceramic heating elements have excellent temperature control and energy-saving characteristics, extremely low thermal inertia, no open flame, no radiation safety, good vibration resistance and other advantages. The reason why PTC heaters are energy-saving is that their output power will decrease significantly with the increase of ambient temperature. When the ambient temperature rises due to heating, the PTC power has decreased under the condition of constant air volume. This feature plays a role in automatic power regulation to a certain extent. On the other hand, it can also be understood that the larger the room temperature, the greater the PTC output power, and the faster the heating. As the room temperature rises, the PTC output power gradually decreases, and the heating effect becomes slower.

High power density is also one of the significant features of PTC heaters. PTC heaters use forced convection to heat the room temperature. Because the heat transfer coefficient of forced convection air is dozens of times that of natural convection, the heat exchange area required to transfer the same amount of heat can be as small as a few tenths. A 100-120W PTC component can be made into a volume as small as 24×15×2.2mm3. This is the key to making PTC heaters compact and light under the same power. Its volume and weight can be as small as about one-fifth of the same power electric oil heater.

Aging attenuation is one of the most important parameters to measure the quality of PTC heaters. The aging speed of PTC components is the fastest in the first 400 hours of use, and then it becomes more and more stable. After 1000 hours of continuous work, the output power of good PTC components is about 10% attenuated, and then it tends to be stable, which has little effect on the heating function of PTC heaters. There are many factors that affect the aging and attenuation of PTC. The high Curie point is the main reason. The higher the Curie point, the faster the aging. In order to save costs and pursue high power unilaterally, some unknown manufacturers often use PTC components with TC ≥ 260℃ to make heaters. There seems to be no problem in the initial use, but as time goes by, the aging and attenuation are obvious.

Constant temperature heating PTC thermistor has constant temperature heating characteristics. The principle is that after the PTC thermistor is powered on, the self-heating temperature rises and the resistance value enters the jump zone. The surface temperature of the constant temperature heating PTC thermistor will remain constant. This temperature is only related to the Curie temperature and applied voltage of the PTC thermistor, and has nothing to do with the ambient temperature.

Constant temperature heating PTC thermistor can be made into a variety of shapes and different specifications. Common ones are disc, rectangle, strip, ring, and honeycomb porous. Combining the above PTC heating elements and metal components can form various forms of high-power PTC heaters.