How a VFD Works

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How A VFD Works: A variable frequency drive is also known as a VFD, variable speed drive, adjustable speed drive, electronic motor controller, or an inverter.  How a VFD Works: Every VFD is unique with its own component characteristics so how each VFD works is dependent upon components within the VFD. Most VFDs integrate a solid state electronics controller consisting of a bridge rectifier, a converter, and an inverter module.

Voltage-source inverter drives are the most common type of VFDs. These drives convert AC line input to AC inverter output. There are some applications that use common DC bus and solar applications. These type of drives are configured as DC to AC drives. The bridge rectifier converter for volts per hertz drives is configured for 3 phase AC electric motors. Volts per hertz drives use a capacitor to smooth out the converter DC output ripple and provides a solid input to the inverter.

This filtered DC voltage is converted to AC voltage output using the inverter’s active switching elements. VSI drives provide higher power factor and lower harmonic distortion (noise) than phase controlled current source inverters and load commutated inverters drives. The drive controller can also be configured as a phase converter having single-phase converter input and three-phase inverter output. Controller advances have allowed increased voltage and current ratings and switching frequency of solid-state power devices over the past 50 years. VFDs were first introduced in 1983, and the insulated gate bipolar transistor has in the past 20 years become the standard for VFDs as an inverter switching device.

In variable-torque applications using Volts per Hertz (V/Hz) drive control, AC motor specifications require that the voltage magnitude of the inverter’s output to the motor be adjusted to match the required load torque in a corresponding V/Hz relationship. For 460 VAC, 60 Hertz electric motors, this V/Hz relationship would be 460/60 = 7.67 V/Hz. While acceptable in a wide range of different applications, V/Hz control is sub-optimal in high performance applications. High performance applications requiring low speed control, demanding high torque, dynamic speed regulation, positioning, and reversing load demands, there are open loop VFDs and closed loop VFDs would be desired over V/Hz VFDs.

How a VFD Works – Manufacturing

Many manufacturers will apply variable frequency drives to rotating equipment to reduce amperage spikes upon start up of large electric motors. Choosing the right VFD for an application will benefit rotating equipment by providing less wear on the electric motors where applied. Adjusting the acceleration and deceleration time of electric motors can extend the lifespan of an electric motor. Variable frequency drives provide the ability to control the frequency of starting and stopping of an AC electric motor. This ability allows an AC electric motor to only operate when needed for the equipment it’s rotating, and electric motors have a longer lifespan if they are only running when they need to be.

Approximately one third of the world’s electrical energy is supplied by electric motors in fixed-speed centrifugal pump, fan, and air compressor applications. These fixed-speed applications hardly ever require the full load speed (RPM) of the electric motor in which they’re operating. By installing a VFD to these applications, electric motor speeds are reduced, and power costs can be reduced by 50% or more. Technology has allowed cost and physical size reduction of variable frequency drives, and has improved performance through advances in semiconductor switching devices, simulation, control techniques, and control hardware and software.

How a VFD Works – Power Savings

The majority of variable frequency drives in the market today contain electronic circuitry that converts 60 Hertz Line power into direct current. The variable frequency drive converts this line power into a pulsed output voltage that duplicates varying alternating current to a desired frequency (speed). A properly applied VFD when paired with the correct electric motor will significantly reduce operating costs for manufacturers. This is particularly true for variable torque loads such as fans, blowers, and pumps. Blowers are often used with dampers to control air flow; these dampers may operate either manually or automatically. When dampers are closed, 50% of the electric motor current will drop to approximately 60% of full load nameplate current. By utilizing variable frequency drives in blower applications, the current draw of the motor will be reduced 30% for every 10% drop in speed. The same electric motor operating from an AC variable frequency drive at 50% speed, will draw approximately 20% of the full load current.

Please watch our YouTube Video to learn more about how a VFD works. For VFD repair and replacement quotes, contact Precision Electric, Inc.

Electrical VFD

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An electrical VFD (variable frequency drive) is also known as a variable speed drive, adjustable speed drive, electronic motor controller, or an inverter. Every electrical VFD is unique with its own component characteristics; so every electrical VFD works dependently upon the components within its VFD. Most electrical VFD’s integrate a solid state electronics controller consisting of a bridge rectifier, a converter, and an inverter module.

A Voltage-source inverter drive is the most common type of electrical VFD. These drives convert AC line input to AC inverter output. There are some applications that use common DC bus and solar applications. These type of drives are configured as DC to AC drives. The bridge rectifier converter for volts per hertz drives is configured for 3 phase AC electric motors. Volts per hertz drives use a capacitor to smooth out the converter DC output ripple and provides a solid input to the inverter.

This filtered DC voltage is converted to AC voltage output using the inverter’s active switching elements. VSI drives provide higher power factor and lower harmonic distortion (noise) than phase controlled current source inverters and load commutated inverters drives. The drive controller can also be configured as a phase converter having single-phase converter input and three-phase inverter output. Controller advances have allowed increased voltage and current ratings and switching frequency of solid-state power devices over the past 50 years. VFDs were first introduced in 1983, and the insulated gate bipolar transistor has in the past 20 years become the standard for VFDs as an inverter switching device.

In variable-torque applications using Volts per Hertz (V/Hz) drive control, AC motor specifications require that the voltage magnitude of the inverter’s output to the motor be adjusted to match the required load torque in a corresponding V/Hz relationship. For 460 VAC, 60 Hertz electric motors, this V/Hz relationship would be 460/60 = 7.67 V/Hz. While acceptable in a wide range of different applications, V/Hz control is sub-optimal in high performance applications. High performance applications requiring low speed control, demanding high torque, dynamic speed regulation, positioning, and reversing load demands, there are open loop VFDs and closed loop VFDs would be desired over V/Hz VFDs.

Electrical VFD Applications

Many manufacturers will apply electrical VFD modules to rotating equipment to reduce amperage spikes upon start up of large electric motors. Choosing the right electrical VFD for an application will benefit rotating equipment by providing less wear on the electric motors where applied. Adjusting the acceleration and deceleration time of electric motors can extend the lifespan of an electric motor. Variable frequency drives provide the ability to control the frequency of starting and stopping of an AC electric motor. This ability allows an AC electric motor to only operate when needed, for the equipment it’s rotating, and electric motors have a longer lifespan if they are only running when they need to be.

Approximately one third of the world’s electrical energy is supplied by electric motors in fixed-speed centrifugal pump, fan, and air compressor applications. These fixed-speed applications hardly ever require the full load speed (RPM) of the electric motor in which they’re operating. By installing an electrical VFD to these applications, electric motor speeds are reduced, and power costs can be reduced by 50% or more. Technology has allowed cost and physical size reduction of variable frequency drives, and has improved performance through advances in semiconductor switching devices, simulation, control techniques, and control hardware and software.

Electrical VFD Power Savings

The majority of electrical VFD modules in the market today contain electronic circuitry that converts 60 Hertz Line power into direct current. The variable frequency drive converts this line power into a pulsed output voltage that duplicates varying alternating current to a desired frequency (speed). A properly applied electrical VFD when paired with the correct electric motor will significantly reduce operating costs for manufacturers. This is particularly true for variable torque loads such as fans, blowers, and pumps. Blowers are often used with dampers to control air flow; these dampers may operate either manually or automatically. When dampers are closed, 50% of the electric motor current will drop to approximately 60% of full load nameplate current. By utilizing variable frequency drives in blower applications, the current draw of the motor will be reduced 30% for every 10% drop in speed. The same electric motor operating from an AC variable frequency drive at 50% speed, will draw approximately 20% of the full load current.

Please watch our YouTube Video, to learn more about electrical VFD modules. An Electrical VFD Is Also Known As A Variable Speed Drive. For Electrical VFD Repair And Replacement Quotes, Contact Precision Electric, Inc. An electrical VFD (variable frequency drive) is also known as a variable speed drive For electrical VFD repair and replacement quotes, contact Precision Electric, Inc.

Adjustable Frequency Drives

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Adjustable frequency drives are also known as adjustable speed drives, variable frequency drives, variable speed drives, VFDs and inverters.

Adjustable frequency drives are solid state electric motor control systems designed to control the speed of an electric motor. Adjustable frequency drives can reduce energy costs up to 50% by speed reduction on electric motors where the full speed of the electric motor is not needed. Drive functions allow an AC electric motor to only operate when needed which allows an electric motor to last longer. Technology has allowed adjustable frequency drives to reduce in cost and physical size and has improved performance through advances in semiconductor switching devices, simulation, control techniques, control hardware, and software.

Approximately one third of electrical energy in the world is supplied by electric motors in fixed-speed centrifugal pump, fan, and air compressor applications. These fixed-speed applications do not usually require full load speed of the electric motor they’re operating. By installing adjustable frequency drives to these applications, electric motor speeds are reduced and power costs can be reduced by 50% or more. Properly applied adjustable frequency drives with electric motors will significantly reduce energy costs for variable torque loads such as fans, blowers, and pumps. Blowers are often used with dampers to control air flow that operate either manually or automatically.  When dampers are closed, 50% of the electric motor current will drop to approximately 60% of full load nameplate current. By utilizing adjustable frequency drives in blower applications, the current draw of the motor will be reduced 30% for every 10% drop in speed. Electric motors controlled by adjustable frequency drives at 50% speed will draw approximately 20% of the electric motor full load current.

Adjustable frequency drives are also used on rotating equipment to reduce amperage spikes upon start up of large electric motors. Adjusting the acceleration and deceleration time of electric motors can extend the lifespan of an electric motor. Using a drive on an electric motor provides the ability to increase or decrease the frequent starting and stopping of an AC electric motor. Limiting the starting and stopping of a motor and controlling the ramp up and ramp down speed of a motor allows for decreased wear on an electric motor. Choosing the right drive for an application can help rotating equipment by providing less wear on the electric motors where applied. Adjustable frequency drives are used in AC servo systems, air compressors, conveyor systems, lathes, mills, plastic extrusion, slitter lines, bottlers, packaging lines, pharmaceutical production, food processing, HVAC systems, waste water treatment systems, submersible pumps, fans, blowers, and many more electric motor applications.

To learn more about adjustable frequency drives or for drive repair and replacement quotes, contact Precision Electric, Inc.

ABB VSD

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ABB VSD drives are designed for motor-driven applications in any industry and all power ranges. ABB VSD drives are compatible with virtually all processes, automation systems, users and business requirements. The innovation behind ABB VSD drives is architecture that simplifies operation, optimizes energy efficiency and helps maximize process output. ABB VSD drives for general purpose applications are designed to control a wide range of applications such as fans, pumps, mixers, conveyors and process control in industries including food and beverage, material handling, chemical, rubber and plastics, and textile and printing. ABB general purpose VSD drives are easy to select, install, configure and use. ABB VSD drives for general purpose applications save users time by using standard built-in features.

ABB VSD Overview

The ACS55 and ACS150 series of ABB VSD micro drives are easy to install and set up. ABB micro drives provide flexible mounting alternatives and straightforward configuration for many basic applications. Each micro drive is tested before it leaves the factory providing high machine availability. ABB local customer and technical support is available no matter where ABB micro drives are delivered and installed.

The ACS355 and ACS850 series of ABB VSD machinery drives are designed to meet the production and performance needs of machine builders, system integration specialists, panel builders and end users in a broad range of applications. ABB VSD machinery drives can be flexibly programmed to meet the demands of different machine solutions. A wide range of features and options provide optimal solutions.

The ACS880 series of industrial VSD drives are designed for fast, cost-effective installations and integration into control cabinets. ABB ACS800 VSD drives enable OEMs, system integrators and panel builders to build their own drive while maximizing benefits from ABB drive technology such as DTC motor control, adaptive programming and a wide range of built-in and external options. ABB provides detailed cabinet installation instructions and other support material to help customers build their own solutions. ACS880 VSD multi-drives are built from ABB industrial drive modules connected to a common DC bus. This enables a single power entry and common braking resources for several drives. This construction simplifies the total installation and results in benefits including savings in cabling, reduced installation and maintenance costs, reduced line currents and more.

The ACS880 single drive module series of ABB VSD drives are complete alternating current drives and can be installed without any additional cabinet or enclosure. ABB single drive modules configuration contains a rectifier, optional EMC filter, reactor, DC link and an inverter in one single AC drive unit. ABB single drives are available as wall-mounted, free-standing and cabinet-built constructions. The key features of ABB single drives are programmability and configurability during both ordering and commissioning, which makes adaptation to different applications easy. ABB’s ACS880 cabinet-built single drives are drives that are mounted into a cabinet and the complete assembly is offered and delivered as one package. Often the cabinet will include additional accessories such as contactors and earth fault protection units. ABB VSD drives for control cabinets are typically built-to-order products.

ABB VSD drives cover a wide power and voltage range, including voltages up to 690 Volt and powers up to 5600 kW. At the core of ABB VSD drives is the Direct Torque Control (DTC), ABB’s DTC is premium motor control technology that enables highly accurate open and closed loop control. ABB VFD drives are designed for industrial applications such as those found in pulp and paper, metals, mining, cement, power, chemical, oil and gas, water and wastewater, and food and beverage.

To learn more about ABB VSD drives, visit the ABB Website. For ABB VSD drives repair and replacement quotes, contact Precision Electric.