The relevant technical requirements for indoor resistance load groups mainly include the following aspects:
Voltage and current:
Rated voltage: It needs to match the voltage of the power supply. Common single-phase AC rated voltages include 220V, 110V, etc. For example, in China, single-phase electricity for civilian use is mostly 220V. If the rated voltage of the load does not match, it may not work properly or even be damaged
Rated current: determined based on the actual power demand of the load, the rated current of the selected load should be greater than or equal to the maximum current during normal operation of the load to prevent overload
Power and power factor:
Rated power: Clearly define the power of the load at rated voltage and rated current. In actual use, avoid operating beyond the rated power for a long time, otherwise it will shorten the load life and even cause safety accidents
Power factor: Low power factor can lead to increased line losses and reduced utilization of power supply equipment. For inductive or capacitive loads, attention should be paid to their power factor, and power factor compensation measures should be taken if necessary
Frequency:
The frequency of single-phase AC power supply in China is usually 50Hz, and in some countries or regions it is 60Hz. The rated frequency of the load should be consistent with the power frequency, otherwise it may affect the performance and lifespan of the load
Insulation and voltage resistance:
Insulation resistance: Reflecting the insulation performance of the load, it is generally required that the insulation resistance be above the specified value (such as megaohm level) to prevent leakage and electric shock accidents
Voltage withstand level: The load should be able to withstand a certain voltage without being broken down, and its voltage withstand value should be higher than the maximum voltage that the power supply may experience to ensure safe use
Load characteristics:
Resistive loads: such as electric heaters, incandescent lamps, etc., with current and voltage in phase and a power factor of 1. The characteristics are stable current, easy to calculate power, but attention should be paid to heat dissipation
Inductive loads: such as motors, transformers, etc., with current lagging voltage and power factor less than 1. During startup, there may be a significant surge current, which requires high power capacity and circuit requirements
Capacitive loads, such as capacitor banks, have current leading voltage and power factor less than 1. Overvoltage and inrush current may occur during input and disconnection, and corresponding protective measures need to be taken
Protection level and environmental adaptability:
Protection level: Choose a load with the appropriate protection level according to the usage environment. For example, IP20 is suitable for general indoor environments, and IP54 can be used in places with certain dust and water splashes
Environmental temperature and humidity: The performance of the load will be affected under different temperature and humidity environments, and the appropriate load should be selected according to the actual usage environment