What is an electric heater? What is the classification of electric heaters?

An electric heater is a device that starts heating after power is supplied. Electric heaters are not only widely used in water heaters, Rice cooker, electric frying pans and Water dispenser, but also widely used in refrigerators and air conditioners.
1、 Classification of electric heaters
According to power, electric heaters can be divided into high-power heaters, medium power heaters, and low-power heaters; According to the structure, electric heaters can be divided into three forms: electric heating tubes, bare wire heaters, and PTC type heaters, which are practical
1. Electric heating tube
This type of electric heater is made by installing resistance wires and adding insulation materials in a circular metal sleeve with crystalline magnesium oxide, as shown in the following figure:
This heater has advantages such as good insulation performance, high power, shock resistance, and moisture resistance.
2. Bare wire heater
The bare wire heater is installed with resistance wire, insulation layer, and porcelain insulator on the bracket. It has the advantages of fast heating speed and high efficiency, but also has the disadvantage of easy leakage. Partial electric heating assistance, heat pump air conditioning uses this type of heater. As shown in the following figure:
3. PTC type heater
PTC type heater is a new type of heater. The PTC heater uses PTC thermistors as a heating device, which has advantages such as long service life, fast heating speed, high efficiency, automatic constant temperature, wide power supply range, and good insulation performance. In addition, the radiator of the heater is made of aluminum alloy, which is then bonded and welded, as shown in the following figure:
2、 Detect electric heater
1. On/off detection
When using electric heating pipes and PTC type heaters, first check for corrosion and looseness in their joints. If so, repair or replace it; If normal, use the resistance of a multimeter to block the resistance between its terminals. If the resistance value is infinite, it indicates that it is turned on. For bare wire heaters, some faults can be detected through visual inspection; If the visual inspection is normal, please use a multimeter for inspection.
2. Testing insulation performance
Place a digital multimeter "200M" resistor or a pointer multimeter "R × 10k "gear, with one lead connected to the pin of the electric heater and the other lead connected to the housing of the electric heater. Under normal circumstances, the resistance value should be infinite, if not, it indicates leakage.