A Detailed Explanation of the Frequency and Speed Inverter
How does a motor drive work?
In the industrial automation sector, the variable frequency drive (VFD) is an essential device comprising a power electronic board (such as IGBT, MOSFET) and a high-speed central control unit (such as microprocessor, DSP). This device is used to drive and manage a single-phase or three-phase electric motor, modulating the frequency and voltage of its power supply to adjust its speed and torque. The process begins by converting alternating current (AC) into direct current (DC) using a rectifier. The direct current is then modulated into a synthetic alternating current waveform by an inverter, enabling the motor's speed to be increased or decreased, offering precise control and more efficient operation.
Nowadays, thanks to software and interface options, the VFD drive has become a high-performance product that enables the user to control motors according to the desired requirements. Fuji Electric has used its expertise, experience and know-how to offer you a selection of the best variable frequency drives on the market, from entry-level to high-end, for your standard or advanced application.
What is the difference between a variable speed drive and a variable frequency drive?
Although the terms are often used interchangeably, it's crucial to understand the difference between these two devices.
- Changing Voltage and Frequency :
- A variable speed drive mainly modifies the voltage applied to the motor to control speed.
- A variable frequency drive, on the other hand, adjusts the frequency of the power supply, which affects both motor speed and torque.
- Applications :
- Variable speed drives are often used in simpler applications where speed control is the only requirement.
- Variable frequency drives (VFDs) are used in more complex applications requiring precise speed and torque control.
- Energy efficiency :
- Variable-frequency drives are generally more energy-efficient than simple variable-speed drives, as they enable more precise and energy-efficient control.
VFDs are also known as variable speed drives, variable frequency drives, AC drives, microinverters and frequency inverters.
What are the applications for frequency inverters?
Variable speed and frequency drives are used in a multitude of fields, offering precise control and energy efficiency.
Fans: Used in suction fans, air handling units, compressors, air conditioning systems, dryers, boiler fans, oven temperature controlgrouped control roofs, refrigerators, film machines, cooling towers, ventilation, diaphragm seals.- Machine tools: Including grinders, sanders, milling machines, lathes, drilling machines, turning tables, positioning machines for machining centers, motherboard drilling machines, winding machines, presses.
- Electric pumps: For use in chillers, potable and tankless water supply systems, submersible motor pumps, vacuum pumps, fountain pumps, cooling water pumps, hot water circulation pumps, well pumps, agricultural storage pumps, water treatment pumps, constant flow pumps, slurry pumps, solar pumps, etc.
- Conveyor equipment: Used in cranes, automated warehouses, conveyors, elevators, parking equipment, elevators, escalators, automatic doors, shut-off equipment.
- Chemical tools / Machine tools for woodworking: Includes fluid mixing machines, extruders, vibrators, diaphragm seals , centrifuges, coating machines, feed rollers, planers.
- Packaging industry: individual and internal packers, wrapping machines, external packers.
- Agri-food processing machines: grain mixing, slicing and grinding machines, tea processing machines, rice milling machines, rice sorting machines.
- Paper industry / Textile machinery: Spinning machines, knitting machines, textile printing machines, industrial sewing machines, synthetic fiber machines, cutting machines.
- Other machines: Automatic mixers for food/medical products, commercial washing machines, offset presses, binders, car washes, shredders, food washing machines, testing equipment, grinders, air screens, automatic blinds, kitchen hoods.
These drives play a crucial role in improving energy efficiency, reducing operating costs, and optimizing productivity in these diverse industrial and commercial applications.
Why use a variable frequency drive?
The use of variable speed drives offers many advantages:
Speed control:The frequency converter modulates motor speed by adjusting the voltage and/or frequency of the power supply. Variable frequency drives (VFDs) are extremely useful in processes requiring precise speed and torque control.- Energy efficiency: By adjusting the motor speed to the needs of the application, the variable speed drive can reduce energy and electricity consumption.
- Reduced operating costs: This converter also enables motors to be started and stopped smoothly. This extends the service life of electric motors.
- Motor protection:Provides protection against phase reversal, overvoltage, undervoltage, overcurrent, and other abnormal conditions that could damage the motor.
- Optimized performance:With precise speed and torque control, the variable speed drive helps optimize the performance and power of motorized systems.
- Energy saving certificate Installing an electronic variable speed drive allows you to benefit from the CEE (Energy Savings Certificate)which contributes financially to your investment, in whole or in part.
However, there are a number of requirements to be met in order to qualify. Maximize your energy savings with this installation, while complying with the required conditions.
How to size a variable frequency drive and how to choose an inverter for a motor?
Sizing a variable speed drive requires a clear understanding of application requirements and motor characteristics:
Motor power :
- Motor power rating must match frequency converter power rating.
- Supply voltage :
- Depending on the mains voltage (220V or 380V), one of two types of variable frequency inverter should be selected: tri/tri input or mono/tri input.
- Frequency :
- The rated frequency of the motor must be compatible with that of the inverter.
- Speed range and load conditions
- Specific application requirements, such as required speed range and load conditions, must be taken into account.
- Protection features :
- Make sure the frequency converter offers the necessary protection against overvoltage, overcurrent and other abnormal conditions.
- Additional features and options :
- Look for products with additional features such as diagnostic functions and communication interfaces, which can facilitate maintenance and improve safety.
- Environmental compatibility :
- Make sure the speed controller is suitable for the operating environment before installation, e.g. temperature and humidity conditions.
- Consideration of Support and Maintenance :
- Take into account the availability of technical support and maintenance services.
- Expert consultation :
- Consult your Fuji Electric variable speed drive manufacturer for recommendations based on your needs.
Technical features and benefits of Fuji Electric variable speed drives
Easy installation and operation- Wide range of power ratings and voltage choices in three-phase and single-phase versions
- User interface with optimized software, integrated console and large LCD display
- Easy parameter setting
- Available in IP21 & IP55 versions
- DCR and EMC filter
- User-customizable language (French, English, etc.)
- Numerous functions: Torque vector control, Overload capability, PID loops, Customizable logic and specific macros, Real-time clock, Unit conversion function
- Numerous communication interfaces available: Modbus RTU, BACnet MS/TP,
- Energy-saving function
- Control functions: Analog input/analog output, PID loop, cascade control
- Safety features: password protection, SIL2 level, fire mode
- Remote control: Extension cable for remote control, man-machine interface
- Approved standards: CE directive (CE marking), UL/cUL
- Control cabinet solutions available
Choose a Fuji Electric variable speed drive
These variable speed drives are more than essential in modern plants, enabling efficient energy management, precise speed and torque control, and contributing to the overall efficiency of motorized systems. By integrating the right drive into your system, you open the door to more efficient operation, lower operating costs and longer equipment life. Mastering these technologies is a step towards smarter, more economical use of energy in a variety of applications. Fuji Electric is your expert in high-performance variable speed drives.
Our mission is to help you understand this equipment. We help you understand their importance and how they work. Finally, we help you choose and size the ideal drive for your specific needs. As a manufacturer of variable frequency drives, Fuji Electric's experts can help you make an informed choice and optimize the performance of your motorized systems: conveyor systems, cooling fans and test benches, as well as special fields such as elevators, pumping and heating, ventilation and air conditioning (HVAC).
FAQ
How to vary the speed of a 220V single-phase motor?
To modulate the speed of a 220V single-phase motor, a suitable variable speed drive is required. It is essential to choose an inverter compatible with the motor's voltage and frequency.
How to choose a variable speed drive for a DC motor?
For a DC motor, it is crucial to choose a drive specifically designed for this type of motor, taking into account the rated output power, voltage and application requirements.
Why a variable frequency drive?
A variable frequency drive offers precise speed and torque control, improved energy efficiency and overload protection, making it indispensable in many industrial and commercial applications.
How to vary the speed of a three-phase motor?
To vary the speed of a three-phase motor, the use of a frequency inverter is the most common and effective method. The variable frequency drive adjusts the frequency of the motor's power supply, enabling precise control of motor speed and torque.
How do you vary the rotation speed of an induction motor?
The rotational speed of an induction motor can be controlled by changing the output frequency of the power supply using a frequency converter.
What is the minimum frequency of a frequency inverter?
In general, most frequency inverters have an output frequency range starting at a few hertz (Hz). The minimum frequency required also depends on the application for which the drive is used. To obtain the minimum frequency for a specific frequency inverter, it is important to consult the technical datasheet supplied by the motor manufacturer. Going below it may result in damage to the motor winding, as the motor may overheat.
Can a single frequency converter power several motors?
It is not possible to control several motors with a single speed controller.
