PTC heater working principle wiring diagram, PTC heater role. The tracking number will take you to learn more about it. 1. PTC electric heater introduction PTC is the abbreviation of Positive Temperature Coefficient, which means positive temperature coefficient, which generally refers to semiconductor materials or components with a large positive temperature coefficient. Usually we mention
PTC heater working principle wiring diagram, PTC heater role. The tracking number will take you to learn more about it.
1. Introduction to PTC electric heater
PTC is the abbreviation of Positive Temperature Coefficient, which means positive temperature coefficient, which generally refers to semiconductor materials or components with a large positive temperature coefficient. Usually we refer to PTC refers to positive temperature coefficient thermistor, referred to as PTC thermistor.PTC thermistor is a typical temperature-sensitive semiconductor resistance, more than a certain temperature (Curie temperature), its resistance value with the increase of temperature step increase.
PTC heater operating principle wiring diagram (role of PTC heater) (Figure 1)
2. Functional principle
Ceramic materials are usually used as excellent insulators with high resistance, while ceramic PTC thermistors are made of barium titanate based on doped with other polycrystalline ceramic materials, with low resistance and semi-conductivity characteristics. This is achieved by purposefully doping a chemically expensive material as a lattice element of the crystal: a portion of the barium ion or titanate ion in the lattice is replaced by a higher valence ion, thus obtaining a certain number of conductive free electrons. For the PTC thermistor effect, that is, the reason for the step increase in resistance value, is that the material structure is composed of many small crystallites, forming a barrier at the interface of the grain, the so-called grain boundary (grain boundary), preventing electrons from crossing the boundary into the adjacent region, thus producing high resistance. This effect is counteracted at low temperatures: high permittivity and spontaneous polarization strength at grain boundaries hinder the formation of barriers at low temperatures and allow electrons to flow freely. At high temperatures, the dielectric constant and polarization strength are greatly reduced, resulting in a large increase in barrier and resistance, showing a strong PTC effect.
PTC heater operating principle wiring diagram (the role of PTC heater) (Figure 2)
Wind speed and power relationship
Generally, in the windless state, the power attenuation rate after 1000 hours of operation with the rated voltage is measured, and the power attenuation rate is required to be ≤ 8%.
PTC heater working principle wiring diagram (the role of PTC heater) (Figure 3)
4. Features of PTC heater
The heater made of PTC ceramic heating element has the advantages of excellent temperature regulation and energy-saving characteristics, extremely low thermal inertia, no open flame, no radiation safety, and good vibration resistance. PTC heater is energy-saving because its output power will be significantly reduced with the increase of ambient temperature, in the case of unchanged air volume when the ambient temperature rises PTC power has decreased, this feature to a certain extent played a role in automatic power adjustment, on the other hand, it can also be understood that the larger the room temperature, the greater the PTC output power, 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 distinctive features of PTC heaters. PTC heater uses forced convection to heat room temperature, because the heat transfer coefficient of forced convection air is dozens of times that of natural convection, so the heat exchange area required to transfer the same heat can be as small as a few tenths, a 100-120W PTC component can be made to 24×15×2.2mm3 such a small volume, which is the same power, PTC heater can be made small and light key, its volume and weight can be as small as about one-fifth of the same power electric heating oil heater. Aging attenuation is one of the most important parameters to measure the quality of PTC heaters, PTC components use the first 400 hours of aging speed is the fastest, and then flattened, after 1000 hours of continuous work, good PTC component output power attenuation of about 10%, and then tends to be stable, which has little impact on the heating function of PTC heaters. There are many factors affecting PTC aging attenuation, the Curie point is high is the main reason, the higher the Curie point, the faster the aging, some miscellaneous manufacturers in order to save costs and one-sided pursuit of high power, often choose TC≥ 260 °C PTC components to make heaters in the early stage of use seems to be no problem, but over time, aging attenuation is obvious.
Constant temperature heating PTC thermistor has constant temperature heating characteristics, the principle is that PTC thermistor after power-on self-heating temperature into the transition zone, constant temperature heating PTC thermistor surface temperature will maintain a constant value, the temperature is only related to the PTC thermistor Curie temperature and applied voltage, and basically unrelated to the ambient temperature.
Constant temperature heating PTC thermistors can be made into a variety of shape structure and different specifications, common are round shape, rectangle, long strip, ring and honeycomb porous, etc. The combination of the above PTC heating elements and metal components can form various forms of high-power PTC heaters.
PTC heaters are classified by conduction method:
(1) PTC ceramic heater based on heat conduction is characterized by multi-layer heat transfer structures such as electrode plate (conductive and heat transfer), insulation layer (power insulation and heat transfer), thermal conductive heat storage plate (some are also attached with thermal conductive glue) installed on the surface of PTC heating element, etc., to transfer the heat emitted by PTC element to the heated object.
(2) Various PTC ceramic hot air heaters for convection heat transfer with the formed hot air are characterized by large output power and can automatically adjust the blowing air temperature and output heat.
(3) Infrared radiant heater, its characteristics actually use the rapid heat emitted on the surface of PTC element or thermal conductive plate to directly or indirectly stimulate the far-infrared coating or far-infrared material that touches its surface to radiate infrared rays, which constitutes a PTC ceramic infrared radiation heater.
Class:
The efficiency and utilization rate of the electric vehicle air conditioning system have a great impact on the cruising range, especially the use of warm air will consume more electric energy, and for gasoline engine cars, because the warm air directly uses the heat dissipation of the engine, so usually the energy consumption of cold air will be greater than that of warm air. The warm air of electric vehicles is actually the process of converting the electric energy of the power battery into heat energy through the heating air device, and most of the current electric vehicles are using PTC (Positive Temperature Coefficient) warm air device, and PTC warm air device can be subdivided into two forms of direct heating air or heating and cooling circulating water and then heating. For example, the i‐MiEV developed by Mitsubishi Motors uses a PTC heater to heat the circulating water, while the leaf unveiled by Nissan at the 2010 Motor Show uses PTC to heat air directly.