Permanent Magnet Servo Motors

Permanent Magnet Servo Motors

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Permanent magnet servo motors are also known as brushless servo motors and/or PM (permanent magnet) servo motors. Permanent magnet servo motors are used when an industrial application requires high performance and precise speed regulation. Permanent magnet servo motors are manufactured with a designated controller known as a servo drive or servo driver. Permanent magnet servo motors use position feedback to precisely regulate motor control by being paired with an encoder. Encoders measure a brushless servo motor’soutput shaft position which is compared to the command position. When the servo motor output shaft doesn’t match the demand signal, an error signal is sent to the servo motor controller; the controller adjusts accordingly and sends a signal back to the servo motor until the demand position is met. PM servo controllers (servo drive, driver, etc.) are never included in the base price of the servo motor. Servo motor systems can be expensive but the cost is justified with optimal manufacturing processes via precise speed regulation.

Servo motors output more torque than brushed direct current motors. Brushless servo motors aren’t as loud during operation than brushed direct current servo motors. The lifespan of brushless servo motors exceeds than that of a brushed direct current motor because there aren’t brushes or a commutator to maintain. The idea behind brushless servo motors was to be able to integrate control function of the servo motor with industrial electronic components and personal computers; and to precisely position machines in manufacturing processes. Some manufacturers use brushless servo motors in explosive and dirty environments because brushless servo motors are entirely closed and sealed to prevent dust or sparks to reach the servo motor parts.

Permanent Magnet Servo Motor Design Process

Permanent Magnet Servo MotorsThis process comprises threemain steps: Electromagnetic, structural and thermal designs. Electromagnetic design startswith magnetic circuit modeling and parameter optimization with a given set of designspecifications. A series of optimizations such as pole number, loading, current density,dimensional limits etc. have to be performed to find the optimum parameters of the motorbefore proceeding further. When a design is obtained that meets the technical spec, a quickmotor simulation and the influence of parameter variation must be carried out usingsimulation software such as SPEED (PC-BDC Manual, 2002). A detailed electromagneticfinite element analysis (FEA) either in 2D or 3D is the next step to verify that the designmeets the specified torque-speed characteristics and performance. After an electromagneticdesign is finalized, structural and thermal analyses (MotorCAD Manual 2004) have to becompleted. Structural analysis is not a necessity for design on low speed permanent magnet servo motors. If motor does not meet the structural or thermal tests, then theelectromagnetic design study should be repeated for a better design.

Permanent magnet servo motors are widely used in many industrial applications for theirsmall size, higher efficiency, noise-free operation, high speed range and better control. Thismakes quality of their torque an important issue in wide range of applications includingservo applications. For example, permanent magnet servo motors used in defense applications, robotics, servosystems, electric vehicles all require smooth torque operation.One of the most important issues in PM servo motors is the pulsating torque componentwhich is inherent in motor design. If a quality work is not completed during the designstage, this component can lead to mechanical vibrations, acoustic noise, shorter life anddrive system problems. In addition, if precautions are not taken, it can lead to seriouscontrol issues especially at low speeds. Minimization of the pulsating torque components isof great importance in the design of permanent magnet servo motors.In general, calculation of torque quality is a demanding task since the torque qualitycalculation does not only consider the torque density of the motor but also consider thepulsating torque component. Therefore, a mathematical approach about torque qualityshould include harmonic analysis of electric drive system rather than a simple sizing of the motor.

To learn more about permanent magnet servo motors or for servo motor repair and replacement quotes, contact Precision Electric, Inc.

 

 

 

 

 

 

 

 

 

 

 

What Is A Variable Frequency Drive

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What is a variable frequency drive? Variable frequencydrives are also known as variable speed drives, VFD’s, adjustable speed drives, and inverters.

Variable frequency drives are solid state motor control systems designed to control the speed of an AC (alternating current) electric motor. Variable frequency drives operate as load controls within AC electric motor applications; and variable frequency drives can reduce energy costsup to 50% by speed reduction on electric motorswhere the full speed (RPM) of the electric motor is not required.Variable frequency drives are used in AC servo systems, air compressors, conveyor systems, lathes, mills, plastic extrusion, slitter lines, food processing, waste water treatment systems, submersible pumps, HVAC fans and blowers, and many more electric motor applications.

Many manufacturers apply AC variable frequency drives to rotating equipment because variable frequency drives reduce amperage spikes upon start up of large electric motors.Choosing the right AC variable frequency drive 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. AC variable frequency drives provide the ability to control the frequency of starting and stopping of an AC electric motor.This ability allowsan AC electric motor to only operate when needed for the equipment it’s rotating, and electric motors have a longer lifespan if they are not continuously operating when they don’t 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 AC variable frequency drives 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 AC variable frequency drives, and has improved performance through advances in semiconductor switching devices, simulation, control techniques, and control hardware and software.

Power Savings: What Is A Variable Frequency Drive

The majority of AC 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 AC variable frequency drive when paired with an AC 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 an AC variable frequency drive in blower applications, the current draw of the motor will be reduced 30% for every 10% drop in speed. The same electric motor operating froman AC variable frequency drive at 50% speed, will draw approximately 20% of the full load current.

Example Application:

A 10 horsepower AC electric motor, rated 90% efficient, operating across the line without an AC variable frequency drive, with the dampers operating between 50 70%, for 2000 hours per year will require 11,996 KWH. If the KWH charge is $.08 per KWH, the cost to run this motor will be: $1,248.00 annually.The same 10 horsepower electric motor operating from an AC variable frequency drive, between 50 70% speed for 2000 hours per year will require 4,676 KWH. Operating cost at the same KWH rate will be: $432.00 per year. This represents a savings of $816.00 per year and should be enough to pay for the AC variable frequency drives investment and installation costs, within the first 12 months of operation.If any electric motor application operates more hours than in the above example, and/orthe KWH charge is higher, the savings will quickly compound.The energy saved on a utility bill from using a variable frequencydrive is often significant enough to pay for the variable speed frequencywithin a couple of months from installation date.Increasing and/or decreasing the start up time on an AC current electric motor via a variable frequencydrive can add years to the motor’s overall lifespan. Using a variable frequencydrive can also improve efficiency on production demands. Variable frequencydrives provide the ability to control the frequency of starting and stopping an AC electric motor.This ability provides a means by which an AC electric motor is only operating when needed. AC electric motors have a longer lifespan if they are not continuously operating when they do not need to be.

Types Of Drives: What Is A Variable Frequency Drive

Volts Per Hertz drives are the most common type of variable frequency drive and areknown as a V/Hz drives, or volts by hertz drives. V/Hz variable frequency drives are used inapplications such as fans, pumps, air compressors, and other related applications wherehigh starting torque is not required. V/Hz variable frequencydrive applications typically do not require full torque when the AC motor is operating at less than the base speed (RPM) of the electric motor. V/Hz variable frequencydrives are the most inexpensive type of variable frequencydrive. V/Hz variable frequencydrives do not provide full motor torque at low RPM.

Open-Loop vector drives are also known as “sensorless vector” variable frequencydrives. Open loop vector drives adapted the name “sensorless vector” because they do not use an external encoder for speed feedback to the motor.Open loop vector drives are used in applications where high starting torque and full torque at low speed (RPM) is required. Open-Loop vector drives operating a motor a zero RPM should not be used on crane or hoist applications. Most open-loop vector drives are used on CNC machines, mixers, mills, lathes, and other applications where high starting torque or full torque at low RPM is needed.Open loop vector drives are usually more expensive than a V/Hz variable speed drives.

Closed-Loop vector drives are used in applications where precise speed control (0.01%) is needed, or in applications where extensive programming is needed. Closed-Loop vector drives use an encoder on the motor to provide constant shaft position indication to the drive’s microprocessor. The encoder feedback allows the drive microprocessor to constantly control torque no matter how many RPM the motor is operating at. Closed-Loop vector drives are used to provide the motor to operate at full torque even at zero RPM. Closed-Loop vector drives are commonly used on hoist and crane applications because crane and hoist motors must produce full torque prior to it’s brake being released, or the load will drop and it will not be able to stop.

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

Yaskawa VFD Drives

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Yaskawa VFD drives are designed to minimize harmful demand for input harmonic distortion. Yaskawa VFD drives up to25 HP are available with optional 3% or 5% equivalent line impedance DC Bus Reactors.At 30 HP and above, Yaskawa VFD drives include 3% impedance as standard. Some Yaskawa VFD drives include a dual diode bridgerectifier which can be configured to accept 12-pulse(delta-delta and delta-wye secondary) transformerinput. Yaskawa VFD drives can also be factory configured with an integral18-pulse transformer. These packages are typicallyused to meet the most strict harmonic requirementsat both drive input terminals and the point of commoncoupling.

Yaskawa VFD drives are factory-programmed and ready torun. An LCD interface enhances ease of use with itsmultiple language support and parameter copy feature thatallows duplication of settings between drives. In addition,a portable USB Copy Unit (1000 series only) providesa very convenient method of desktop configurationtransportable to the factory floor.All Yaskawa VFD drives have a split cover for easy access to thepower and control terminals. The power terminal compartmenteasily accommodates bend radius for cable connections. Controlwires are connected to a detachable terminal board for ease ofinstallation and maintenance.

Detachable cooling fans are easy to replace and on/off fan controlcan extend operating life. Accumulated operation time and coolingfan run time are recorded and can be displayed for preventivemaintenance programs.Start-up and configuration are simplified by the intuitiveprogramming menu and start-up procedure.DriveWizard Industrial is a PC-based support tool for drivecommissioning and maintenance. It provides a way to operatethe drive, change parameters, upload and download parameters,monitor and graph parameters, provide status and troubleshootingdata, and utilize a host of additional features with built-in helpmenus.

Yaskawa VFD Drives Product Overview

Yaskawa VFD DrivesThe Yaskawa A1000 is a multi-purpose VFD drive deliveringup to 1000 horsepower, and provides Yaskawas highest levelof vector performance including precise controlof both induction and permanent magnet motors.The Yaskawa A1000 VFD drive is a full featured drive, providing outstanding quality,performance, flexibility, and environmental friendliness through 1000HP.Enjoy network communications, feedback, and expandable I/O to controlanything from simple fans and pumps to complex machines. For newinstallations or retrofits, the Yaskawa A1000 VFD drive provides a single robust solution,regardless of the application.

The Yaskawa G7 VFD drive is the ultimate performancesolution with increased speed and torque response to provide servo-likeperformance from an induction motor. The Yaskawa G7 VFD drive has theworlds first 480V 3-level inverter architecture that eliminates orminimizes the installation problems associated with IGBT switching andprotects the entire motor-drive system. The Yaskawa G7 VFD drive performance makes it the ideal drive for high performancespeed, torque, or position control applications. Several control modesare provided in the G7. In open loop vector mode, the latest flux observeralgorithms extend speed range and provide maximum starting torque.In closed loop vector mode, 0.01% speed regulation and 1000:1 controlrange can be achieved. Zero-servo capability provides position controlat zero speed.

The Yaskawa P1000 VFD drive is the next generation in Industrial Fan and Pump control,designed for those applications that are variable torque. Simplicity,intuitiveness, and user friendliness were the key factors in the Yaskawa P1000 VFD drive design. The Yaskawa P1000 VFD drive includes a powerful set of pre programmedfan/pump application macros allowing for quick and easycommissioning. With its advanced motor control algorithm alongwith the next generation IGBT technology, motor noise and drivepackaging is reduced. The P1000 supports a wide range of network andcontrol options providing for the most cost effective solution.

The Yaskawa J1000 VFD drive is a general purpose AC drive; its PWM designprovides low motor noise and high starting torque, with a heavy dutycurrent overload rating of 150% for 60 seconds and a normal dutycurrent overload rating of 120% for 60 seconds. Volts per hertz control makesthe Yaskawa J1000 VFD drive suitable for most general applications. The J1000 is feature packed,low cost and compact. The digital operator includes a 5-digitLED status display. TheYaskawaJ1000 VFD drive has five multi-function digital inputs,one multi-function analog input, one multi-function digital output,and one multi-function analog output. An optional RS-422/485Modbus RTU serial communication port is available. An ideal choicewhenever low cost and small size are required.

The Yaskawa V1000 VFD drive is a high performance line of AC micro drives withlow motor noise and high starting torque. It provides two controlmethods; Volts per hertz,and open loop current vector control for precise speedregulation and higher torque at lower speeds. The Yaskawa V1000 VFD driveis intendedfor either heavy duty applications or normal duty applications. The Yaskawa V1000 VFD drive is the perfect choice wherever highperformance in a small size is required.

To learn more about Yaskawa VFD drives, please visit the Yaskawa Website or contact Precision Electric.

 

 

 

 

 

dc variable speed drives, abb 500 horsepower control cabinet

DC Variable Speed Drives

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The first electric motors were designed and built for operation from direct current power.The following should be considered when choosing DC variable speed drives for production:

  • Wide speed range
  • Good speed regulation
  • Compact size and light weight
  • Ease of control
  • Low maintenance
  • Low cost

dc variable speed drive, 500 horsepower ABB variable speed drive

In order to determine if DC variable speed drives have the capability to provide the above characteristics, the DC drive has to be analyzed as two elements that make up the package. These two elements are the electric motor and the control.General purpose DC motors used on nearly all packaged drives have a very simple performance characteristic; the motor shaft turns at a speed directly proportional to the voltage applied to the armature.The Armature amperage of a DC motor is almost directly proportional to output torque regardless of speed. This characteristic indicates that a small fixed amount of current is required to turn the motor even when there is no output torque. This is due to the friction of the bearings, electrical losses in the motor materials and load imposed by the air in the motor winding.

DC motor speed is primarily determined by the applied armature voltage and DC motor torque is controlled by armature current.Understanding these concepts of DC motors provides the key to understanding the performance of DC variable speed drives. DC variable speed drives use a control module. This control module rectifies alternating current power and converts it to direct current for DC motor control. The control module also controls the DC output voltage and amperage in response to various control and feedback signals. The feedback signals then regulate the DC motor performance via speed, and torque.

The regulating function of DC variable speed drives provide an electronic circuit that monitors a number of inputs and sums these signals to produce an error signal. This error signal is processed and transformed into precisely timed pulses that are applied to the gates of the Silicon Controlled Rectifier(SCR) in the power bridge, thereby regulating the power output to the DC motor.In order to control DC motor speed accurately it is necessary to provide DC variable speed drives with a feedback signal related to motor speed. The standard method of doing this in a simple control is by monitoring the armature voltage and feeding it back into the regulator for comparison with the input set point signal.When armature voltage becomes high, relative to the set point, established by the speed potentiometer setting, an error is detected and the output voltage from the power bridge is reduced to lower the motor’s speed back to the “set point”. Similarly when the armature voltage drops an error of opposite polarity is sensed and the control output voltage is automatically increased in an attempt to re-establish the desired speed. The “Armature Voltage Feedback System” which is standard in most packaged drives is generally called a “Voltage Regulated Drive”.

A second and more accurate method of obtaining the motor speed feedback information is called “Tachometer Feedback”. In this case the speed feedback signal is obtained from a motor mounted tachometer. The output of this tachometer is directly related to the speed of the motor. Using Tachometer Feedback gives a DC variable speed drive improved regulation characteristics. When “tach feedback” is used the drive is referred to as a “Speed Regulated Drive”. Most DC drives are capable of being modified to accept tachometer signals for operation in the tachometer feedback mode.In some newer high performance “digital drives” the feedback can come from a motor mounted encoder that feeds back voltage pulses at a rate related to motor speed. These (counts) are processed digitally being compared to the “set point” and error signals are produced to regulate the armature voltage and speed.

In addition to the normal external adjustment such as the speed pot, there are anumber of common internal adjustments that are used on simple small analog type DC variable speed drives.The following is a description of the functions that these individual adjustments serve and theirtypical use.

Adjustments Of DC Variable Speed Drives & Motors

DC Variable Speed DrivesIn most cases when DC variable speed drives are initially installed, the speed potentiometer can be turneddown to its lowest point and the output voltage from the drive will go to zero, then the motor will stop.There are many situations where this is not desirable, because there are some machinesthat need to be kept running at a minimum speed and accelerated up to operating speed asnecessary. There is also a possibility that an operator may use the speed potentiometer tostop the motor to work on the machine. This can be a dangerous situation since the motor hasonly been brought to a stop by zeroing the input signal voltage. A more desirable situation iswhen the motor is stopped by opening the circuit to the motor or power to the control usingthe on/off switch. By adjusting the minimum speed up to some point where the motorcontinues to run even with the speed potentiometer set to its lowest point, the operator mustshut the control off to stop the motor. This adds safety into the system. The typicalminimum speed adjustment is from 0 to 30% of motor base speed.

The maximum speed adjustment sets the maximum speed attainable either by raising the inputsignal to its maximum point or turning the potentiometer to the maximum point. On a typicalDC motor the rated speed of the motor might 1750 RPM but the control might be capable ofrunning it up to 1850 or 1900 RPM. In some cases it’s desirable to limit the motor (and machinespeed) to something less than would be available at this maximum setting. The maximumadjustment allows this to be done. By turning the internal potentiometer to a lower point themaximum output voltage from the control is limited. This limits the maximum speed availablefrom the motor.

Digital DC variable speed drives are capable of constantly monitoring the DC motor current. The current drawn by the armature of theDC motor is related to the torque that is required by the load. Since this monitoring and controlis available an adjustment is provided in the drive that limits the output current to amaximum value.This function can be used to set a threshold point that will cause the motor to stall ratherthan putting out an excessive amount of torque. This capability gives the motor/drive combination the ability to prevent damage that might otherwise occur if higher values oftorque were available. This is handy on machines that might become jammed or otherwisestalled. It can also be used where the drive is operating a device such as the center winderwhere the important thing becomes torque rather than the speed. In this case the current limitis set and the speed goes up or down to hold the tension 0f the material being wound. Thecurrent limit is normally factory set at 150% of the motor’s rated current. This allows the motorto produce enough torque to start and accelerate the load and yet will not let the current(and torque) exceed 150% of its rated value when running. The range of adjustment istypically from 0 to 200% of the motor rated current.

IR compensation is a method used to adjust for the droop in a motor’s speed due to armature resistance. As mentioned previously, IR compensation is positive feedback that causes thecontrol output voltage to rise slightly with increasing output current. This will help stabilize the motor’s speedfrom a no load to full load condition. If the motor happens to be driving a load where the torque isconstant or nearly so, then this adjustment is usually unnecessary. However, if the motor is driving a loadwith a widely fluctuating torque requirement, and speed regulation is critical, then IR compensationcan be adjusted to stabilize the speed from the light load to full load condition. One caution isthat when IR compensation is adjusted too high it results in an increasing speed characteristic. This meansthat as the load is applied the motor is actually going to be forced to run faster. When thishappens it increases the voltage and current to the motor which in turn increases the motor speed further. If thisadjustment is set too high an unstable “hunting” or oscillating condition occurs that is undesirable.

The Acceleration Time adjustment performs the function that is indicated by its name. It willextend or shorten the amount of time for the motor to go from zero speed up to the set speed. It alsoregulates the time it takes to change speeds from one setting (say 50%) to another setting(perhaps 100%). So this setting has the ability to moderate the acceleration rate on the DC variable frequency drive.If an acceleration time that’s too rapid is called for, “accelerationtime” will be overridden by the current limit. Acceleration will only occur at a rate that is allowed by theamount of current the control passes through to the motor. On most small DC variable speed drives, the acceleration time is not linear. What this means is that a change of 50 RPM may occur more rapidly when the motor is at low speed than it does when the motor is approaching the set pointspeed. This is important to know but usually not critical on simple applications where these drives are used.This is an adjustment that allows loads to be slowed over an extended period of time. Forexample, if power is removed from the motor and the load stops in 3 seconds, then the deceleration timeadjustment would allow an increased time and “power down” the load over a period of 4, 5, 6 ormore seconds.

To learn more about DC variable speed drives or for DC variable speed drive repair and replacement quotes, contact Precision Electric, Inc.

 

 

Information References:

http://www.fincor.net

 

 

 

 

 

 

 

 

 

 

types of vfd drives

Types Of VFD Drives

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There are 3 general types of VFD drives:

Each of these types of VFD drives can be divided into different variations. Every type of VFD drive system runs an electric motor and a speed control unit. VFD drive technology in today’s manufacturing processes mainly consist of solid state electronic components in a single control system. Older VFD drive systems use mechanical moving parts that in short periods of time, result in equipment failure due to worn parts from constant motion.

Eddy Current Systems – Types Of VFD Drives

types of vfd drivesThese types of VFD drives use an eddy current electric motor system. An eddy current type of VFD drive consists of a fixed speed motor and an eddy current clutch. The clutch contains a fixed speed rotor and a variable speed rotor separated by a small air gap. A direct current in a field coil produces a magnetic field that determines thetorquetransmitted from the input to the output rotor. The controller provides closed loop speed regulation by varying the clutch current, allowing the clutch to transmit enough torque to operate at the desired speed. Speed feedback is provided by an integral AC tachometer.

Eddy current VFD drives are less efficient than all other types of variable frequency drives.Nearly all eddy current motor drive systems are obsolete today. Eddy Current motor drives were designed and manufactured decades ago and there are very few manufacturing facilities across the globe that still use them in production. When an Eddy Current motor drive system fails, it’s usually too expensive to repair and impossible to replace. When an Eddy Current motor drive reaches the end of its life cycle and can no longer be repaired, manufacturers retrofit the Eddy Current Drive Systems with an AC Induction Motor and an AC VFD Drive system.

DC Systems – Types Of VFD Drives

types of vfd drivesThese types of VFD drives use DC (direct current) electric motors. DC (direct current) motors have a rotating armature winding (winding in which a voltage is induced) but non-rotating armature magnetic field, and a static field winding (winding that produces the main magnetic flux) or permanent magnet. Different connections of the field and armature winding provide different inherent speed/torque regulation characteristics. The speed of a DC motor can be controlled by changing the voltage applied to the armature or by changing the field current. The introduction of variable resistance in the armature circuit or field circuit allowed speed control. Modern DC motors are often controlled bypower electronicssystems called DC VFD drives.

There are different types of DC VFD drives, but the most common are known as DC Motor Speed Control Systems.The speed of a DC motor is directly proportional to armature voltage and inversely proportional to motor flux; either armature voltage or field current can be used to control the motor speed. DC Motors have become expensive and today most DC motor speed control systems are retrofitted with an AC induction motor and AC VFD drive. AC VFD drives are less expensive than DC Drive systems, are more available, and are more energy efficient than DC VFD Drive systems.

AC Systems – Types Of VFD Drives

types of vfd drivesThese types of VFD drives use AC (alternating current) electric motors. AC VFD drives are also known as Variable Frequency Drives, VSDs (variable speed drives), AFDs (adjustable speed drives), inverters, and micro drives. AC variable frequency drives are used in many applications such as AC Servo Systems, Air Compressors, Conveyor Systems, Lathes, Mills, Food Processing production lines, Waste Water treatment systems, Submersible Pumps, HVAC fans and blowers, and many more applications.Approximately one third of the world’s electrical energy is supplied by electric motors in fixed-speed centrifugal pump, fan, and air compressor applications. This proves thatsignificant energy efficiency improvement opportunities are available if older DC motor speed control systems and eddy current drive systems are retrofitted with AC variable frequency drive systems.Most industrial manufacturers replace their eddy current and DC variable frequency drive systems with AC variable frequency drive systems.

Technology has reduced the physical size and cost of AC variable frequency drives, and has improved performance through advances in semiconductor switching devices, simulation, control techniques, and control hardware and software.Manufacturers capitalize on AC VFD drive technology to save money on power consumption, increase quality control, decrease production downtime, and improve overall efficiency on production lines.

 

Information References:

 

 

 

 

ac variable frequency drives - bottling line

AC Variable Frequency Drives

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ac variable frequency drives - bottling lineAC variable frequency drives are also known as VFDs, VSDs (variable speed drives), AFDs (adjustable speed drives), inverters, and micro drives. AC variable frequency drives are used in AC Servo Systems, Air Compressors, Conveyor Systems, Lathes, Mills, Plastic Extrusion, Slitter Lines, Food Processing, Waste Water Treatment Systems, Submersible Pumps, HVAC Fans and Blowers, and many more applications.

Many manufacturers apply AC variable frequency drives to rotating equipment because variable frequency drives reduce amperage spikes upon start up of large electric motors.Choosing the right AC variable frequency drive 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 an electric motor’s lifespan. AC variable frequency drives provide the ability to control the frequency of starting and stopping of an AC electric motor.This ability provides a means by which an AC electric motor is only operating when needed for the equipment it’s rotating, and electric motors have a longer lifespan if they are not continuously operating when they don’t 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 AC variable frequency drives to these applications, the motor speeds are reduced, and power costs can be reduced by 50% or more. Technology has reduced cost and physical size of AC variable frequency drives, and has improved performance through advances in semiconductor switching devices, simulation, control techniques, and control hardware and software.

Power Savings Via AC Variable Frequency Drives

ac variable frequency drives - bottling lineAC variable frequency drives are used to reduce power savings in food processing, plastic extrusion, waste water treatment, and many other applications.AC variable frequency drives operate as load controls within applications that may accomplish up to 50% reduction in energy costs. Electric motors will turn at a rate proportional to the frequency of the alternating current (AC) applied to it.

The majority of AC 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 AC variable frequency drive when paired with an AC electric motor, will significantly reduce operating costs. This is particularly true for variable torque loads such asFans,Blowers, andPumps.Blowers, for example, 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 an AC variable frequency drive in this application, current draw in the motor will be reduced 30% for every 10% drop in speed. The same electric motor operating froman AC variable frequency drive at 50% speed, will draw approximately 20% of the full load current.

Example Application: AC Variable Frequency Drives

ac variable frequency drives - bottling lineA 10 horsepower AC electric motor, rated 90% efficient, operating across the line without an AC variable frequency drive, with the dampers operating between 50 70%, for 2000 hours per year will require 11,996 KWH. If the KWH charge is $.08 per KWH, the cost to run this motor will be: $1,248.00 annually.The same 10 horsepower electric motor operating from an AC variable frequency drive, between 50 70% speed for 2000 hours per year will require 4,676 KWH. Operating cost at the same KWH rate will be: $432.00 per year. This represents a savings of $816.00 per year and should be enough to pay for the AC variable frequency drives investment and installation costs, within the first 12 months of operation.If any electric motor application operates more hours than in the above example, and/orthe KWH charge is higher, the savings will quickly compound.

Manufacturers across the globe capitalize on AC variable frequency drives to save money on power consumption, increase quality control, decrease production downtime, and improve overall efficiency. To learn more about AC variable frequency drives or for repair and replacement quotes, contact Precision Electric, Inc.

 

 

 

 

 

energy saving vfd

Energy Saving VFD

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Over the past decade, energy saving VFD drives have allowed to become a cost efficient way to reduce power costs and increase system production efficiency. 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 don’t always require the full load speed (RPM) of the electric motor in which they’re operating. By installing an energy saving VFD drive to these applications, the motor speed is reduced, and power costs can be reduced by 50% or more.This energy savings is often significant enough to pay for energy saving VFD drives within a few months.

Energy Saving VFD – Applications

Energy saving VFD drives are used in many applications such as swimming pool pumps, air compressors, conveyor belts, lathes, mills, food processing, plastic extrusion, waste water treatment pumps, HVAC fans and blowers, and many more. Energy saving VFD drivesare used in manufacturing to increase or decrease the acceleration and deceleration times on alternating current (AC) motors.

Adjusting the acceleration and deceleration time on electric motors can extend the motor’s lifespan, and can also improve efficiency on production demands. Energy saving VFD drives can also provide the ability to control the frequency of starting and stopping an AC motor.This ability provides a means by which an AC electric motor is only operating when needed for the equipment it’s rotating, and electric motors have a longer lifespan if they are not continuously operating when they don’t need to be.

energy saving vfdUtilizing energy saving VFD drives can greatly increase power savings in food processing, plastic extrusion, waste water treatment, and many other manufacturing sites. Many manufacturers apply energy saving VFD drives to their rotating equipment because they reduce amperage spikes upon start up of large electric motors.Choosing the right energy saving VFD drive for an application will increase power savings on utility bills, increase production flow, and will benefit rotating equipment by providing less wear on the electric motors where applied.

The use of energy saving VFD drives on variable torque loads for the purpose of gaining energy savings is a common goal. VFD drives operate as load controls within applications that may accomplish up to 50% reduction in energy costs.In general, an electric motor will turn at a rate proportional to the frequency of the alternating current (AC) applied to it.The majority of VFD drives in the market today contain electronic circuitry that converts 60 Hertz Line power into direct current. The VFD converts this line power into a pulsed output voltage that duplicates varying alternating current to a desired frequency (speed).A properly applied energy saving VFD Drive will significantly reduce operating costs. This is particularly true for variable torque loads such as:

  • Fans
  • Blowers
  • Pumps

Blowers, for example, are often used with dampers to control air flow. These dampers may be operated 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 an energy saving VFD drive in this application, current draw in the motor will be reduced 30% for every 10% drop in speed. The same electric motor operating froman energy saving VFD drive, at 50% speed, will draw approximately 20% of the full load current.

Example Application:

A 10 horsepower AC electric motor, rated 90% efficient, operating across the line (without an energy saving VFD) with the dampers operating between 50 70%, for 2000 hours per year will require 11,996 KWH. If your KWH charge is $.08 per KWH, the cost to run this motor will be: $1,248.00 annually.

The same 10 horsepower electric motor operating from an energy saving VFD Drive, between 50 70% speed for 2000 hours per year will require 4,676 KWH. Operating cost at the same KWH rate will be: $432.00 per year. This represents a savings of $816.00 per year and should be enough to pay for the energy saving VFD investment and installation costs in the first 12 months of operation.

If any electric motor application operates more hours than in the above example, and/orthe KWH charge is higher, the savings will quickly compound.

Energy Saving VFD – Repair Versus Replacement

In our ever growing world of technology, energy saving VFD drives have over the past decade allowed to become a cost efficient way to reduce power costs and increase system efficiency. Today manufacturers around the globe within a wide range of industries are finding more ways to apply energy saving VFD drives to their rotating equipment.From past experience, smaller horsepower VFD drives typically fail in eight years and are more often replaced rather than repaired.

Larger horsepower VFD drives last longer by virtue of repairs that often require replacement of circuit boards and other electrical components. After bearing the cost of two or three replacement boards in any one VFD drive, the user often realizes that the drive should have been junked sooner.

 

 

 

Eaton VFD Troubleshooting

Eaton VFD Troubleshooting

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Eaton VFD TroubleshootingEaton VFD troubleshooting begins with technicians working with the VFD in production. Eaton VFD troubleshooting can be time consuming, so manufacturers tend to keep spare Eaton drives on hand for production lines that cannot afford downtime.When Eaton VFD troubleshooting cannot be resolved in the plant, technicians in the field are known to send their Eaton VFD to the original equipment manufacturer or Eaton VFD repair centers for repair and replacement options. The original equipment manufacturer of Eaton drives and Eaton VFD repair centers usually only offer a replacement for failed drives, but this isn’t usually the most economical solution for manufacturers.

Eaton VFD troubleshooting and VFD repair centers are an asset to manufacturers who use Eaton drive products, and Precision Electric is the best source for Eaton VFD troubleshooting and Eaton VFD repair.Precision Electric has been performing Eaton VFD Troubleshooting and Eaton VFD Repair since 1983.Precision Electric has helped save manufacturers thousands of dollars by repairing their failed Eaton VFD drives in lieu of of replacing Eaton VFD drives.

When Eaton VFD troubleshooting leads to Eaton VFD repair, the repair process should be taken with extreme caution. Eaton VFD repair should only be performed by technicians who have required training and experience to work with electrical equipment. Precision Electric strongly recommends to consult an expert in the field when repairing and troubleshooting Eaton VFD equipment.

The troubleshooting techniques for each brand of VFD can be unique, but the overall structure of troubleshooting always remains the same.The ultimate goal when performing Eaton VFD troubleshooting is to diagnose, repair and re-commission the unit as quickly as possible, and these are the steps that Precision Electric follows before anydis-assembly takes place.

1. Take Notes –Eaton VFD Troubleshooting

This is often a subject that is passed by many individuals who are attempting to troubleshoot industrial electrical equipment. Before Precision Electric begins to perform Eaton VFD troubleshooting, qualified technicians take note of many important aspects of the equipment including, but not limited to:

    1. Eaton VFD Model Number
    2. VFD Serial Number
    3. Reason for Service
    4. Urgency (Rush Overtime or Standard)
    5. Visual Inspection of External Device

2.Diode and IGBT Tests –Eaton VFD Troubleshooting

Eaton VFD TroubleshootingWhen Eaton VFD Troubleshooting exceeds parameter changes, Precision Electric tests the input and output power sections of the Eaton VFD. This step is essential prior to applying power to the VFD unit. If for any reason there is a short on the input side or output side of the VFD, further damage can be caused to the unit if power is applied to it.

For this reason, Precision Electric uses meters to properly test the input and output power sections of the Eaton VFD prior to applying power to the actual unit. If a short is found, the unit can be disassembled and the cause of the short can be diagnosed and quoted for repair. If the repair is too costly, then a replacement is offered to the customer.

3. Power Up –Eaton VFD Troubleshooting

If the input and output power sections test healthy during this step of the Eaton VFD troubleshooting and repair process, Precision Electric will power up the unit and perform amp reading and output frequency tests. Precision Electric prefers to slowly increase power voltage to the unit until the rated input voltage of the VFD is achieved.

Depending on whether or not the VFD provides a display will determine what further action(s) will be taken. If display is unavailable, dis-assembly and diagnosis of the internal power supply of the control section of the VFD is likely necessary to further evaluate cause of failure and establish cost and lead time for the Eaton VFD repair.

4. Run A Motor – Eaton VFD Troubleshooting

Eaton VFD TroubleshootingIf the previous three tests have passed during the Eaton VFD troubleshooting and repair process, then it is time to run a basic jog function of the VFD with a simple template program. Often when a VFD comes into our facility, we make sure to backup whatever program is currently stored in the VFD prior to inputting a template program and running a test procedure. This is to ensure we have a backup copy of the program.

The best method for backing up depends on the brand of drive, but after it has been backed up, we either reset the Eaton VFD to factory defaults through the keypad and recommission a basic start, stop and job application or closed loop if an encoder is involved. If the motor will not run, it will be necessary to check the output voltages and current ratings going to the motor to see if the VFD is functioning properly to rotate the motor.

5. Contact Customer – Eaton VFD Troubleshooting

At this point we have determined the cause of failure, estimated lead time and cost of the Eaton VFD troubleshooting and VFD repair. If the VFD has tested good entirely, then further underlying issues are communicated with the customer. This is when Precision Electricwill gather application specific information from the customer to establish whether or not it may be some outside issue associated with the system including, but not limited to, PLC communications, faulty IO, bad wiring or even bad cabling. There is no single way to do this step, as it depends on a wide variety of variables.

6. Send Service Tech – Eaton VFD Troubleshooting

If the customer cannot establish failure on any other aspect of the machine and the Eaton VFD troubleshooting tests appear to be good, then it may be necessary to send a Precision Electric field service technician on site to establish cause of failure. Precision Electricfield service technicians are trained to troubleshoot any issue ranging from standard VFD repair to advanced robotics, servo systems, electric motor issues and more. Precision Electric field technicians are trained to establish cause of failure and come up with solutions as quick as possible.

To learn more about Eaton VFD Troubleshooting or for Eaton VFD Repair Quotes, contactPrecision Electric, Inc.

 

 

 

 

 

 

ABB DCS800 VFD

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ABB DCS800 VFDThe practical requirements of a modern DC VFD are extremely diverse. A DC drive should be full of features and easy to use which sometimes, isn’t a simple task. The challenge is to find an innovative solution which excels in both, and the solution, is the ABB DCS800 VFD.

The ABB DCS800 VFD offers a simple interface and rich feature set, offering ease of commissioning and smooth adaptation to specific applications. The ABB DCS800 VFD has the widest power ranges in the industry from 10 horsepower through 2,500 horsepower in single VFD module packages and solutions through 1200 volts and 20,000 amps.

The ABB DCS800 VFD has the most advanced digital controller of any DC drive on the ABB power platform. This means that there are 16-bit analog input / output; 5 millisecond response time for overriding control; and integrated speed, torque, PID, and voltage controls as standard features. This makes the automatic tuning feature of the ACS800 simple to commission, macros to simplify setup, and adaptive programming feature that allows ease of custom requirements within the application. The ABB DCS800 VFD is the latest digital technology on a proven power platform.

ABB DCS800 VFD Programming and Communications

ABB DCS800 VFDAdaptive Programming (AP) offers the ability to customize the drive to needs without installation of additional hardware to the ABB DCS800 VFD. Adaptive Programming within the ABB DCS800 VFD also allows the user to change how a digital output works, add a PI Controller, and filter an analog input. The DCS800 can be programmed with the control panel or by using the ABB PC-Based software, DriveWindow Light, which is included with every ACS800 VFD. Adaptive Programming features the flexibility users need to make the drive work to required specifications.

ABB offers a wide range of software to make accessing, programming and diagnostics easier to communicate with the ACS800 than ever before. DriveWindow Light is a powerful PC-Based tool to start up and interface with the ACS800, and DriveWindow Light is included with every ACS800 drive module. More complex applications and systems use High Speed DriveWindow Tool with a host of features, high speed data, and clear graphical presentation of the application operations that make it a valuable addition to any DC Drive System.

For Control Builder users, ABB CoDeSys offers all t he tools needed to create and modify applications. If additional programming or software is needed beyond the CoDeSys, ABB will provide control builders with its own web page with full internet access.

ABB DCS800 VFD Adaptability

The ABB DCS800 VFD functionality increases according to the requirements of the DCS800 user. The user has the ability to include plug-in options such as field bus modules, input / output extension modules, and fiber-optic communication modules. ABB’s field bus alternatives feature full access to drive control and status words to system diagnostics. This makes the choice of automation systems completely independent from the choice of using an ABB DCS800 VFD versus the competition. The ABB DCS800 VFD also offers the adaptability of Control Builder; Control Builder is a tool that puts fully programmable PLC (prgrammable logic control) inside the drive. Control Builder can modify the drive operation, interface, or create entirely new functions for the application equipment.

To learn more about the ABB DCS800 VFD, please visit the ABB Website or contact Precision Electric, Inc.

 

Information References:

 

  • http://new.abb.com/us
  • http://www.abb.com/product/us/9AAC113388.aspx?country=US
  • http://www05.abb.com/global/scot/scot204.nsf/veritydisplay/7e9e66c8d3dea67ec1257a090044cea7/$file/3adw000192r0601%20dcs800%20technical%20catalog%20e%20f.pdf

 

 

 

 

 

 

 

 

SVX9000

SVX9000 VFD

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Eaton SVX VFDEatonsSVX9000VFD (variable frequency drive) is thecompact, modular solution to adjustable speed applications. The SVX9000 VFD enables a broad range of new application capabilities, and option cards allow the to configurethe VFD to meet any requirement. With its wide voltagerange, high overload ability, and user-friendly alphanumericalkeypad,SVX9000VFD Drivesare the smart decision forevery user.

There are just three screws that link thecontrol module to the powermodule on the SVX9000 VFD. SVX9000 VFD controlunits are interchangeable withinframe sizes while software,control panels, I/O andcommunication cards arecommon throughout the line.Separating the power andcontrol units provides installationadvantages and reduced spareparts requirements. Forconvenience, theSVX9000VFD isfield convertible from Type 1 toType 12 (frames 46). Itsreduced size equates to lesspanel space used and easyretrofits.

Even when the drive isunpowered, theSVX9000VFDcanbe programmed and tested.The control logic module can bepowered from an external +24Volts DC source so youre ready totrain, test and go live wheneverneeded. Whether you chooselocal or remote operations viathe keypad, simple copy/pastefunctions streamline processes.

TheSVX9000may be configuredwith several differentcommunication protocols,making it easy to communicatewith all commonly used controlsystems. The control unitspowerful microprocessor can beused for local control tasks,thereby freeing resources of thecontrol system for other controltasks. 9000XEngine, Eaton’sversatile block-programmingtool, eliminates the need for aPLC and significantly simplifiesthe control system.

SVX9000 VFD Programming Software

SVX90009000XLoad For SVX9000 VFD

9000XLoad is an easy-to-usetool for the SVX9000 VFD, to upload system,application and option cardsoftware intended for use byengineering, commissioning andservice personnel. 9000XLoad isalso suitable for loading customapplications to the SVX9000 VFD.

9000XDrive For SVX9000 VFD

9000XDrive is a software toolthat allows uploading anddownloading SVX9000 VFD parameters.Parameters can be changed,saved, and uploaded to anynumber of SVX9000 VFD drives.The tool has the ability to printparameters or save them to afile for future use and reference.Parameters can be compared todefault values to determine drivesetup. Operator functions includethe ability to set references,start and stop the drive, andto monitor signals and actualvalues. These values can bedisplayed via a graphic display.

9000XEngine For SVX9000 VFD

Create IEC 1131-3 compliantcustom applications with9000XEngine for the SVX9000 VFD. This graphicaldesign tool customizes thecontrol logic and parameters inthe SVX9000 VFD. Functional BlockDiagram (FBD), Ladder Diagram(LD) and Structured Text (ST)are all part of the functionset. 9000XEngine enables thecreation of parameters, faultmessages and other application relatedfeatures.

To learn more about the Eaton SVX9000 VFD, visit the Eaton Website or contact Precision Electric, Inc.

 

 

Information References:

http://www.eaton.com/Eaton/ProductsServices/Electrical/ProductsandServices/AutomationandControl/AdjustableFrequencyDrives/IndustrialDrives/SVX/index.htm

 

 

 

ABB Low Harmonic Drives

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Harmonic distortion may disturb or damage sensitive equipment connected to the same circuit of a variable speed drive. Any distorted voltage and current waveform that deviates from the ideal waveform presents the potential to harm electronic components, which can result in expensive repairs and production downtime. Non-linear loads connected to the electrical supply in industrial and commercial facilities insert harmonic distortion on the power distribution system.

A non-linear load application included solid state electric motor soft starts, variable speed drives, personal computers, electronic lighting, welding equipment and other power supplies that are not interrupted. Harmonic distortion can cause distribution transformers and supply cables to overheat; resulting in the breakdown of electrical insulation and failure; electronic display failure, circuit breaker tripping and other damage resulting in distorted readings by metering equipment.

Taking action to solve harmonic distortion provides many benefits beyond managing risk. Industries with high power consumption such as paper and pulp, metals, oil and gas refineries, cement and chemical processing, have the opportunity to optimize the power quality in these facilities by managing the disturbances and losses that are caused by harmonic distortion.

A Single Solution to Harmonic Distortion

ABB Low Harmonic DrivesHarmonic standards are becoming stricter and there is a growing demand for low harmonic drive solutions. The ABB ACS800-U31 variable speed drive offers an easy solution to the problem of harmonics. The solution itself is incorporated within the variable speed drive, eliminating the need for any additional filtering equipment or complicated large multiple pulse transformer installations.

The ABB ACS800-U31 eliminates low order harmonics with the active converter controlled with DTC technology and high order harmonics with an LCL line filter. The result is exceptionally low harmonic content within the network that exceeds the requirements made by IIEEE519 at the drive input terminals. Even on the weakest AC line network the ACS800-U31 can be a solution to harmonic distortion. The ABB ACS800-U31 provides a simple, compact and complete solution to meet power quality standards.

The ABB ACS800-U31 doesn’t require a dedicated multiple pulse transformer so the installation time is significantly reduced with regards to cabling and wiring processes. The ABB ACS800-U31 also requires less physical floor space which also makes ease of installation. The ABB ACS800-U31 always operates with unity power factor of 1 and is impervious to alternating current line voltage imbalances up to and over 3%. The system efficiency also is better than 12 and 18 pulse drive solutions since there isn’t a phase shifting transformer required for applications.

The ACS800-U31 is a ultra low harmonic wall mounted drive and is available in power ratings from 208-240 voltage from 10 horsepower through 60 horsepower; and 380-480 voltage from 20 horsepower through 125 horsepower.

To learn more about ABB ACS800-U31 low harmonic drives, please visit the ABB Website.

 

Information References:

 

 

 

 

 

Variable Frequency Drives for Wastewater

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The flow and pressure of fans and pumps need to be controlled because water consumption varies during a day.The flow and pressure can be adjusted either electrically with variable speed drives or mechanically with fixed-speed solutions such as inlet guide vanes, throttling valves or hydraulic couplings. The most common flow control method is by means of a fixed speed motor regulated with a valve. This method can be compared to adjusting the speed of a car by braking while keeping the foot on the gas pedal. This technique doesn’t only waste a tremendous amount of energy, it also wears out the equipment. With variable frequency drives, changing the flow is achieved by adjusting the motor speed which can be compared to reducing the speed by taking the foot on the gas pedal and switching the automobile into lower gear. Wastewater pumps are operated at best efficiency point under all operating conditions when using a variable frequency drive with the application. Variable speed drives are the most efficient control method because they save energy and they decrease water emissions while minimizing total operating costs.

Variable frequency drives can also reduce maintenance overhead at waste water plants by acting as soft starters when applied to electric motors; because they reduce the stress on bearings, motor windings, housings and other equipment. The variable frequency drive progressively increases the motor speed and accelerates the corresponding load to the rated RPM of the motor. When sized correctly, one variable frequency drive can be setup to operate several wastewater pumps in sequence.

Using a variable frequency drive for soft starting electric motors eliminates high starting currents and voltage dips that normally would cause breakers to trip on overload fault. When a wastewater pump is turned off or if the water demand is reduced, a variable frequency drive can slowly reduce the speed of the pump to avoid water hammering, stress on pumping equipment and electric motor parts, resulting in an extended lifetime of wastewater pumps and electric motors. A pump running at half its rated RPM consumes as little as one eighth of the energy compared to a pump running at full rated RPM.Wastewater pumps usually operate at partial load so a huge potential in energy savings can be achieved by controlling a pump’s RPM with a variable frequency drive. Applying a variable frequency drive to wastewater pumps instead of operating across the line, an energy bill can be reduced by as much as 60 percent and this consequently helps to reduce water emissions.

ABB Drive Solutions for Wastewater Pumps

Variable Frequency Drives for WastewaterThe ABB ACS 2000 ULH direct-to-line configuration combines the cost savings of a variable speed drive systems without using a transformer and features the benefits of a voltage source inverter, including excellent availability, reliability, and high, constant power factor with superior control performance.

The ABB ACS 2000 drive features an active front end combined with multiple levels of control. The result is an ultra-low harmonic design that minimizes line harmonics without the use of expensive, custom transformers. The ABB ACS 2000 also includes a smaller, lighter weight packaged product to minimize the overall space required in the maintenance room while reducing shipping and installation costs.

Power ratings of the ABB ACS 2000 series drives range from 400 kVA through 300 kVA to 2000 horsepower.and 4.16 kV, 6.0 kV to 6.9 kV. The ABB ACS 2000 series drive is commonly used on influent, effluent pumps, aeration blowers, cooling fans, intake pumps and other related wastewater equipment.

To learn more about the ABB ACS 2000 series drive, please visit the ABB Website.

 

Information References: