Many people have seen inverter refrigerators or inverter air conditioners in their homes and offices in recent years. Inverter appliances are available in many stores and online. Inverter appliances are popular because they are energy-efficient. The inverter’s operation is not explained by salespeople or even in commercials.
What is an Inverter?
Inverters can also refer to AC Drives or VFDs (variable-frequency drive). They can transform DC (Direct Current), into AC (Alternating Current). It controls speed and torque for electric engines.
The majority of devices we use for our work include electric motors. These motors run on electricity. It is crucial to match the motor speed to the desired process in order to prevent energy wastage. In factories, wasteful energy and materials can put your business at risk. Therefore, inverters are used for controlling electric motors. They increase productivity while saving energy.
Technology Behind Power Conversion and Motor Control
An AC drive operates between an electric motor or power supply. The AC drive controls the AC power. The motor is then supplied with the regulated power.
An AC drive includes a rectifier, a DC intermediate and an inverse circuit. An AC drive can have a unidirectional rectifier unit or a bidirectional one. The latter can be used to accelerate or run the motor by using the energy available in the electrical network. A bidirectional rectifier is able to extract the mechanical rotation energy from a motor and transmit it back into the electrical system. An inverse conversion unit can be used by a DC circuit, which stores the electrical power.
Before the motor can receive the regulated current, it goes through a process within the AC drive. The AC voltage is converted into DC voltage by the rectifier unit. The DC intermediate circuit smoothens DC voltage. It flows through an inverse conversion circuit, which converts DC voltage back to AC voltage.
This allows the AC driver to adjust the frequency or voltage that is supplied to the motor to meet the needs of the process. Higher frequency output voltages result in a motor that runs at a faster speed. This allows the operator interface to control the motor’s speed.
Benefits
1. Energy-saving
AC drives can be used to control fan and pump motor rotations. AC drives offer a superior alternative to dampers or on/off switches. By controlling motor rotation, they can reduce energy consumption up to 20% to 50%. It works in the same way as reducing a car’s speed. The accelerator can be used to reduce the car’s speed.
2. Soft Starters
AC Drives are used to start motors by delivering power at low frequencies. It gradually increases frequency and motor speed until desired speed is reached. It is possible to adjust the speed and frequency at any moment. This is useful for conveyor belts and escalators, as it prevents load drops.
3. Controlled starting current
It takes seven to eight times the AC motor’s full load current to start the motor. AC drives decrease the starting current. This results in fewer motor wind-ups and a longer motor life.
4. Minimized power line disruptions
The voltage can rise if an AC motor is started across the line. This can lead to a significant drain on the power distribution network. A large motor can cause sensitive equipment, such as sensors and computers to trip. AC drives reduce voltage sag by taking the power out of the motor and preventing it from tripping.
5. It is easy to change the direction of rotation
AC drives can be used for frequent start/stop operations. You only need a small current in order to change the direction or rotation of the motor after you have changed the rotation command. Stand mixers can produce the desired output in the same direction as the rotation command. A 24v 5000w inverter drive allows for the control of the number and speed of the revolutions.
6. Simple Installation
AC drives can be pre-programmed. All auxiliaries, communication and motor lines are pre-wired for control power. The contractor needs to only connect the line with the power source that will supply AC drive.
7. Adjustable Torque Limit
AC Drives protect motors by precisely controlling the torque. The motor will continue turning until the overload switch is activated. You can set an AC drive to limit the torque applied to the motor in order to not exceed the torque limit.
8. Elimination of all Mechanical Drive Components
AC drives can deliver the speed required by loads without using gearboxes and speed-increasing/reduction devices. This allows for lower maintenance costs and reduces floor space requirements.
Low and medium Voltages
AC drives are divided into two types: Low Voltage, (LV), and Medium Voltage. There are many things to take into consideration when buying AC drives.
An LV-drive can output 240 to 600 volts alternating current (VAC). They are often used in pumps, compressors, conveyor belts, etc. Low maintenance is required because LV drives put less strain on the motor. It also uses less energy. A LV drive can produce higher frequency and better motor performance at low Voltage, thereby reducing production costs.
However, lower voltage generates more current. If LV drives can be used with high horsepower (HP), machines, it will generate more heat and raise the room temperature. Increased current means more heat is generated. It is important to install vents and add air-conditioning.
MV drives are used to power huge, multi-megawatt motors in power plants and metal processing facilities. They produce 4160 VAC but can reach up to 69,000 VAC. For high output voltage, they need a high input current. MV drives have higher costs and require more costly transformers and breakers. They are physically larger than LV drives. Unlike LV drive, which can only be maintained by an electrician in-house, MV drives require regular maintenance.
Conclusion
Regular consumers and companies both strive to conserve energy. This has led to the creation of inverters for machines and appliances. Inverters are concealed and kept in areas with good ventilation. However, inverters play a significant role in energy conservation. You can reduce your energy consumption and produce less waste by adjusting the control of office devices to meet demand.
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