Application areas of frequency converters :
1. Air conditioners
Office buildings, shopping malls, supermarkets, and factories all have central air conditioning systems, which consume a significant amount of electricity during the summer peak season. In hot weather, air conditioning accounts for more than 40% of peak electricity consumption in Beijing, Shanghai, and Shenzhen. Therefore, using variable frequency drives (VFDs) to power the chilled water pumps and fans in air conditioning systems is an excellent energy-saving technology. Currently, many companies across the country specialize in air conditioning energy saving, with variable frequency speed control being their primary technology.
2. Crusher type load
Crushers and ball mills are widely used in metallurgy, mining, and building materials industries, and frequency conversion has shown significant effects on these types of loads.
3. Large kilns and calcining furnaces
Previously, most large industrial rotary kilns ( converters ) in metallurgy, building materials, and caustic soda industries used DC motors, commutator motors, slip-ring motors, cascade speed regulation, or medium-frequency generator speed regulation. However, due to the presence of slip rings or low efficiency of these methods, many units have adopted frequency converter control in recent years, with excellent results.
4. Compressor-type loads
Compressors are also widely used loads. Low-pressure compressors are commonly used in various industrial sectors, while high-pressure, large-capacity compressors are widely used in steel ( such as oxygen generators ) , mining, fertilizer, and ethylene industries. Variable frequency speed control offers advantages such as low starting current, energy savings, and extended equipment lifespan.
5. Rolling mill loads
In the metallurgical industry, large rolling mills used AC - AC frequency converters in the past, but in recent years they have adopted AC - DC - AC frequency converters. The AC conversion of rolling mills has become a trend, especially in light-load rolling mills. For example, the multi-stand aluminum rolling mill of Ningxia National Aluminum Products Factory uses a general-purpose frequency converter to meet the requirements of low-frequency load start-up, synchronous operation between stands, constant tension control, and simple and reliable operation.
6. Hoist type loads
Variable frequency speed control (VFD) is used for winch-type loads, ensuring stability and reliability. Blast furnace winches in ironworks are the primary equipment for conveying raw materials in ironmaking. They require smooth starting and braking, uniform acceleration and deceleration, and high reliability. Previously, cascade, DC, or rotor resistance speed control methods were commonly used, resulting in low efficiency and poor reliability. Replacing these methods with AC VFDs achieves ideal results.
7. Converter type load
For converter-type loads, using AC frequency converters to replace DC units is simple, reliable, and provides stable operation.
8. Roller conveyor loads
Roller conveyor loads are mostly used in the steel and metallurgical industry. Using AC motor frequency conversion control can improve the reliability and stability of the equipment.
9. Pump loads
Pumps are a wide range of loads, including water pumps, oil pumps, chemical pumps, mud pumps, sand pumps, etc., ranging from low-pressure small and medium-capacity pumps to high-pressure large-capacity pumps.
Many water pumps used by water companies, chemical pumps in the chemical and fertilizer industries, reciprocating pumps, and mud pumps in the non-ferrous metals industry have adopted variable frequency speed control, which has produced very good results.
10. Loads from cranes and dump trucks
Cranes and dump trucks, among other loads, require high torque and stable operation, frequent forward and reverse rotation, and high reliability. Variable frequency drives (VFDs) can meet these requirements for controlling cranes and dump trucks.
11. Loads for wire drawing machines
The wire drawing machine for producing steel wire requires high-speed, continuous production. The steel wire strength is 200 kg/mm² , and the speed control system requires high precision, high stability, and synchronization.
12. Loads of transport vehicles
Variable frequency technology ( VFD ) has proven highly effective in coal mine loading vehicles and steel mill molten steel transport vehicles. It allows for rapid start-up and shutdown, strong overload capacity, and flexible forward and reverse rotation, ensuring a level coal surface and accurate weight (neither overloading nor underloading ) . It essentially eliminates the need for manual operation, thereby improving raw coal production efficiency and saving energy.
