How Do VFDs Work

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How Do VFDs Work?A variable frequency drive is also known as a VFD, variable speed drive, adjustable speed drive, electronic motor controller, or an inverter. How do VFDs work? 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 usea 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 Do VFDs Work In Manufacturing

Many manufacturers will apply variable frequency drivesto 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 its rotating, and electric motors have a longer lifespan if they are only running when they need to be.

Approximately one third of the worlds 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 theyre 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 Do VFDs Work For 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.

Are you still asking yourself, How Do VFDs Work? Please watch our YouTube Video,or contact us via email. For VFD repair and replacement quotes, contact Precision Electric, Inc.

Eaton Overcurrent Protection

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Eaton overcurrent protection and Eaton current control for the Eaton9000X drive is based on motor current measurement in all three phases. In the Frame 9/ Chassis 61 Eaton drives, the current sensors are built into the IGBT SKIP modules, and the current signals are combined and fed into a 14-bit A/D converter on the lower ASIC board. The ASIC board sends the current levels to the control board via a fiber optic serial link. In the smaller Eaton Frame 8 / Chassis 5 drives (and below), the measured current signal is fed directly to the control board. The EatonSVX9000drive has a 10-bit A/D converter and the EatonSPX9000drive has a 14-bit A/D converter.

Eaton overcurrent protection for the 9000X air-cooled frequency converter ratings are based on a High Overload (IH) capability. This means the drive can provide 150% rated output current for 1 minute if the drive was operating at rated output current (IH) for at least 9 minutes. To get continued 150% overcurrent capability, the average current over the duty cycle cannot exceed the rated output current. The maximum drive output current (IS) for starting produces approximately 200% rated motor torque but because the currents are vector sums, IS is less than 200% IH. The drive can deliver IS for 2 seconds every 20 seconds. The drive current limit can be set to 200% (2 x IH) to deliver IH but to reduce the chance of an overcurrent or IGBT over temperature trip, it is better to set the current limit to 150% (1.5 x IH) or less.

The actual drive output current available to the motor is dependent on ambient temperature at the intake to the drive, restrictions in airflow to the drive, and the drive frame size. Drive frames FR4FR9 can deliver rated current (IH) at 50C. Drive frames FR10 and above can deliver rated current (IH) at 40C except for the highest ratings of a drive frame, which may be limited to 35C. The Low Overload (IL ) rating is typically used for variable torque loads where an overload is not necessary even though a 1 (out of 10) minute overload of 110% is allowed. All drive frames are limited to 40C or less for the IL rating. The rated currents of each frame depend on a reduction of switching frequency when unit temperature reaches the warning level.

Eaton overcurrent protection in the liquid-cooled drive has a Thermal maximum continuous rms current (Ith). Use this value for continuous or any overload requirements of the process. The liquid-cooled drive does not have a 1-minute overload current rating. The thermal current rating is dependent on proper coolant flow to each module and a module coolant inlet temperature of 30C. Current limit (software-function) The drive will attempt to limit drive output current to the current limit setting by overriding and lowering the frequency reference until current is within the current limit setting. If unit temperature nears the warning level, the drive will reduce the output frequency in an attempt to bring drive output current down to a continuous current that is approximately the Low Overload (IL ) current rating. The control will not allow any further overcurrent conditions until the average current over the duty cycle is less than the drives current rating. The liquid-cooled drive control will attempt to limit the output current to the current limit setting up to the drives thermal rating. The application should be designed to avoid using the current limiter for control.

The safest way to operate an Eatondrive is to keep the drive output current within ratings with appropriate ramp times or a controlled reference to the drive. If the drive software cannot prevent output current from exceeding 200% IH, a current cutter stops firing the IGBTs when the measured instantaneous value of the current exceeds 360% IH to reduce current quickly before an overcurrent trip occurs. They are re-fired on the next top of the triangle wave. The current cutter is active on select units FR8/CH5 and smaller. If the measured instantaneous value of current exceeds the trip limit value (260400% depending on drive size), all IGBTs are switched off and the drive displays an F1, overcurrent trip. The drive is protected from a short circuit at the motor if the motor leads are greater than 16 feet (5m) in length.

Only trained and experienced electricians should work withEaton overcurrent protection. For more safety information about Eaton overcurrent protection, visit the Eaton Website. For Eaton drive repair and Eaton drive replacement quotes, contact Precision Electric.

What Is A VFD?

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VFD is an abbreviation that stands for Variable Frequency Drive. VFD’s arealso known as variable frequency drives, variable speed drives, adjustable speed drives, electronic motor controllers, orinverters.

VFD’s aresolid 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.VFD’s 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 will apply a VFD to rotating equipment to reduce amperage spikes upon start up of large electric motors.Choosing the right VFDfor 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 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 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.

VFD 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 froman AC variable frequency drive at 50% speed, will draw approximately 20% of the full load current.

VFD 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 is usually 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.

VFD Types

Volts Per Hertz drives are the most common type of VFDand 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 frequency 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 VFD’s, please watch our YouTube Videobelow this post. For VFD repair and replacement quotes, contact Precision Electric, Inc.

Eaton HVAC Frequency Drives

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Eaton HVAC frequencydrives were specifically engineered for HVAC, pump and fluid control applications. The power unit makes use of the most sophisticated semiconductor technology and a highly modular construction that can be flexibly adapted to the customers needs. The input and output configuration (I/O) is designed with modularity in mind. The I/O is compromised of option cards, each with its own input and output configuration. The control module is designed to accept a total of five of these cards. The cards contain not only normal analog and digital inputs but also field bus cards.

The HVX series of Eaton HVAC frequencydrives are obsolete and replaced by Eaton H-MAX drives.The HMAX series of Eaton HVAC frequency drives are designed to the HVAC market for fan, pump, and fluid control applications. The patented energy savings algorithm, high short-circuit current rating and intuitive user interface provide customers an energy efficient, safe, and easy to use solution for adjustable frequency drive needs.The H-MAX drive supports the increasing demand for energy savings in buildings, systems and facilities. Built in capabilities and unique features provide a competitive solution that can add value to any end user.

MVX9000 And M-MaxEaton HVAC Frequency Drives

The MVX9000 series of Eaton HVAC frequency drives are microprocessor-based, sensorless vector drives that provide adjustable speed control for three-phase motors. MVX9000 drives come with standard features that can be programmed to customize the drive’s performance to suit a wide variety of applications, and they include a digital display with operating and programming keys on a removable keypad.

MVX9000 series of Eaton HVAC frequency drives are obsolete and replaced by Eaton M-MAX drives.The M-Max Drive is a compact micro drive with a broad power range. The M-Max series of Eaton HVAC frequency drives feature conformal board coating, unique mounting characteristics, simple programming, and 50C Rating to makethe M-Max perfectly suited for machinery applications in many industries. Typical applications for the M-Max Eaton drive include Food and Beverage, HVAC, Packaging, Pumping, Textile, OEM, and more.

The M-Max series of Eaton HVAC frequency drives key features include:

  • Global acceptance
  • 50C ambient temperature environments
  • Conformal coating standard
  • Modbus-RTU as standard serial fieldbus
  • Side-by-side mounting and orientation flexibility to maximize panel space
  • Temperature controlled cooling fan to increase efficiency and extend life
  • On-board start-up wizard and preset macros to simplify commissioning
  • NEMA 1 kits available

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

Lenze Drives

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Rapidly changing times present manufacturerswith new and varied challenges. To succeed in the future, manufacturerswill need to handle more extensive tasks in even shorter time frames. Lenze drives create the best possible solution to set ideas in motion for optimizing an existing machine or develop new machines. Lenzeis one of the leading drive and automation specialists in the field of machine engineering.

SMV Series
The SMV series of Lenze drives range from IP31 (NEMA 1) and IP65 (NEMA 4/NEMA 4X). The SMV series of Lenzedrives offer sophisticated auto-tuning, fast dynamic toque response with impressive low-speed operation all from a compact and simple to use package. The SMV range is designed for motor applications where dynamic speed and torque control is demanded, making the units ideal for conveyors, food production lines, packaging equipment plus fan & pump systems.The SMV series of Lenze drives use a price leadership tradition in the highly competitive AC drive market. With the benefit of a two year warranty, the SMV series of Lenzedrives offerperformance and flexibility make it an attractive solution for a broad range of applications including:

  • Food processing machinery
  • Packaging machinery
  • Material handling/conveying systems
  • HVAC systems

The SMV series of Lenze drives use price leadership in delivering unparalleled performance and simplicity. The SMV series of Lenze drives is the right choice forperformance, power, packaging and intuitive programming. The Lenze SMV series of Lenze drives use anElectronic Programming Module (EPM) for programming. The Lenze EPM makes for ease of hassle-free reconfiguration within each parameter or resetting the drive to factory or user default settings. When drive reset is necessary, reset to factory default or customer settings in seconds with the EPM. When the EPM equipped drive is used on a line containing multiple drives with the identical setup, it takes just minutes to program the entire line. And EPMs can be replaced with or without power connected. When a drive must be replaced, the parameter configuration is not lost, simply plug in the pre-programmed EPM.

MC Series
The MC Series of Lenze drives are the intelligent, versatile and cost-effective choice for industrial applications. From harsh environments to high torque loads, the MC M1000 Series drives meet the toughest requirements with reliability, at a low cost. The MC Series is easy-to-program and offers full features, extensive I/O, and a full array of programmable functions. The M1000 is available in a power range of 1/4 to 150 HP and voltages ranging from 115 to 575 VAC. With its Enhanced Torque System (ETS), a highly efficient sine coding algorithm and auto-voltage boost, the M1000 delivers maximum starting and accelerating torque and tight speed regulation, even under fluctuating load conditions. A built-in, UL-approved thermal overload provides full motor protection. M1000 drives feature manual boost for high starting torque, auto-boost for high torque acceleration at any speed, power-up & auto restart modes, sleep mode with adjustable speed threshold and time. Adjustable units display: Hz, RPM, %, /SEC, /MIN, and /HR. Slip compensation is for tight speed regulation even under fluctuating loads and control configuration uses local, remote, both, serial communications and auxiliary outputs – two open collector outputs and a Form C relay. Dynamic Braking is available for faster stopping or deceleration time. Additional form-C relay and remote keypad is also available (up to NEMA 4X rating).All MC Series options can be factory installed or field installed.

M3000 Series
The M3000 series of Lenze Drives arefor process control demands with fast acceleration and response. Lenze M3000 series drives are designed expressly for use where the motor control is an integral part of a process, the M3000 is rated for constant torque applications but can easily be configured for variable torque applications. Most process control drives are designed for variable torque applications where the motor is driving a centrifugal fan or pump. As such, these drives are limited to 110% current for overload situations such as acceleration or responding to a feedback change. The MC3000 is a true Constant Torque drive rated for 180% of rated current for 30 seconds and 150% for one minute; this allows faster response to system changes and the ability to apply the MC3000 to non-centrifugal applications such as compressors, conveyors and other constant torque loads. The M3000 is available in the same power ranges and voltages as the M1000.
MCH Series
The MCH series of Lenze drives are available for output power from 1 HP to 250 HP (0.18 to 185 kW).The MCH series of Lenze drives were designed for the HVAC market and the specific requirements of Industrial and Commercial installations.The MCH series Lenze Drives are designed to operate standard polyphase induction motors rated from 200VAC – 575VAC from 0 to 120Hz. The MCH Series Lenzedrives offer intuitive operator interface using simpleprogramming and operational information. The MCH series of Lenze drives allow drive software to adjust the motor speed to maintain a preset pressure, flow, temperature or other variables using PID setpoint control. The MCH Series of Lenze drives are HVAC drives and include UL and cUL approved motor protection for single motor applications. The MCH Series of Lenze drives has been specifically designed for HVAC loads such as fans, pumps and cooling towers. The application specific keypad offers easy operation.

Inverter Repair

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Most inverterrepair can be prevented with routine maintenance. Inverter repair costs and lead times can also be reduced with routine maintenance. Inverterrepair can be expensive and also cost manufacturers production downtime while the inverter repair is in process.Most manufacturers stock spare inverter modulesto prevent production downtime in the event of an inverter failure.Components used forinverter modules are often cheaply made and prone to failure. Knowledgeable inverter repair shops should replace cheaply made components with high quality components during the inverter repair process. Using high quality components in an inverter repair ensures a higher chance of success and a longer lifespan during production.

Connections
Checkingconnections is a step many people miss or do incorrectly during the inverterrepair process. Heat cycles and mechanical vibration can lead to sub-standard connections, as can standard preventative maintenancepractices. Reusing torque screws is not a good Idea, and further tightening an already tight connection can ruin the connection.Bad connections eventually lead to arcing. Arcing at the inverterinput could result in nuisance over voltage faults, clearing of input fuses, or damage to protective components. Arcing at the inverteroutput could result in over-current faults or even damage to the power components.

Loose connections can cause erratic operation. Loose START/STOP signal wires can cause uncontrollable inverterstarting and stopping. A loose speed reference wire can cause the drive speed to fluctuate, resulting in scrap, machine damage, or personnel injury.

Conduct Diode and IGBT Tests
There are a number of methods to test the input and output power sections of an inverter, and this step is essential prior to applying power to the inverterunit. If for any reason there is a short on the input side or output side of the inverter, 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 inverter 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 offeredto the customer.

Power Up Unit
If the input and output power sections test healthy during this step of the inverter repair process, Precision Electric will power 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 inverter is achieved.

Depending on whether or not the inverter 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 inverter is likely necessary to further evaluate cause of failure and establish costand lead time for the inverter repair.

Run A Motor
If the previous three tests have passed during the inverter repair process, then it is time to run a basic jog function of the inverter with a simple template program. Often when an inverter comes into our facility, we make sure to backup whatever program is currently stored in the inverterprior to inputting a template program and running a test procedure. This 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 inverterto 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 checkthe output voltages and current ratings going to the motor to see if the inverteris functioning properly to rotate the motor.

Contact Customer
At this point we have determined the cause of failure, estimated lead time and costof the inverterrepair. If the inverter 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 really depends on a wide variety of variables.

Send Service Tech
If the customer cannot establish failure on any other aspect of the machine and the inverterappears to test fine, then it may be necessary to send a field service technician on site to establish cause of failure. Field service technicians should betrained to troubleshoot any issue ranging from standard inverterrepair, to advanced robotics, PLCs and more. Field technicians should also be trained to establish cause of failure and come up with solutions as quick as possible.

Inverter repair should be taken with extreme caution. Inverterrepair 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 or installinginverterequipment.Many invertercontrollers have an internal DC bus that retains a charge after power has been cut to the drive, as a result, it does not mean it’s safe to work with. Technicians working with inverter repair must always take extra precautions to ensure proper safety measures are taken, or injury or even death may occur.

For inverterrepair and inverter replacement quotes, contact Precision Electric.

Inverter Drives

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Inverterdrives are also known as variable frequency drives, VFD’s, variable speed drives, adjustable frequency drives, AFD’s, adjustable speed drives and ASD’s. Inverterdrives are solid state motor control systems used to regulatethe speed of alternating (AC) electric motors. Inverter drives are mainly used to reduce energy consumption on electric motors for industrial manufacturers.

Inverterdrives operate as load controls within applications that may accomplish up to 50% reduction in energy costsby speed reduction on applications where the full speed (RPM) of the electric motor is not required. Inverterdrives 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 AC motor applications.

Many manufacturers apply inverterdrives withrotating equipment toreduce amperage spikes upon start up of large electric motors.Choosing the right inverterdrive for an application will benefit rotating equipment by providing less wear on the electric motors where applied; by adjusting the acceleration and deceleration time of electric motors, an electric motor’s lifespan is extended significantly. Inverter 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 they’re operating. By installing inverter 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 inverterdrives, and has improved performance through advances in semiconductor switching devices, simulation, control techniques, and control hardware and software.

Power Savings With Inverter Drives

The majority of inverter drives in the market today contain electronic circuitry that converts 60 Hertz Line power into direct current. The inverterdrive converts this line power into a pulsed output voltage that duplicates varying alternating current to a desired frequency (speed).A properly applied inverterdrive 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 inverterdrive at 50% speed, will draw approximately 20% of the full load current.

Types Of Inverter Drives

Volts Per Hertz inverter drives are the most common type of drive and areknown as a V/Hz drives, or volts by hertz drives. V/Hz inverterdrives are used inapplications such as fans, pumps, air compressors, and other related applications wherehigh starting torque is not required. V/Hz drive 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 drives are the most inexpensive type of variable frequencydrive. V/Hz drives do not provide full motor torque at low RPM.

Open-Loop vector inverter drives are also known as “sensorless vector” drives. 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 V/Hz inverterdrives.

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 inverterdrives or for inverter drive repair and replacement quotes, contact Precision Electric, Inc.

VFD Drives

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VFD drives are known as Variable Frequency Drives. VFD drives are also known as variable speed drives (VSDs), adjustable speed drives, motor speed controllers and inverters. VFD drivesare solid state controllers used in AC or DC electric motor applications. Most VFD drives are applied on alternating current (AC) electric motors in the industrial manufacturing world. There are some direct current (DC) electric motor applications that apply variable frequency drives, but most manufacturers seek AC motors because DC motors are expensive and they’re more prone to failure. VFD drives can also be used as a phase converters when three phase motors need to be operated from single phase power.

VFDdrives areused in mills, lathes, fans, air compressors, pumps, conveyors, welders, robots and many other electric motor applications to control the speed regulation of an electric motor. Over 30 percent of the world’s electrical energy is consumed by electric motors in fixed-speed fan, pump, and air compressor applications. The basic idea for using a VFD on mills, air compressors, and fans is to decreasethe amount of electrical energy being consumed toreduce electricity costs.

Energy Savings

Only about3% of the total installed AC electric motors in the United States use VFDdrives.An estimated 60-65% of electrical energy in the United States is used to supply electric motors, and 75% of that electrical energy is consumed by fan, pump and air compressor applications.Approximately 18% of the electrical energy used in the 40 million motors in the United States could save power consumption via efficient energy improvement by using VFD drives on these electric motor applications.

Performance and Operation

VFDdrives are applied to alternating current (AC) electric motors to increase quality control and reduce energy consumption during the process of manufacturing.VFD drives increase quality control by monitoring the electric motor speed, pressure, temperature, torque, and tension; and then adjusting the motor to operate as economical as possible to meet the VFDcriteria.

Fixed-speed electric motor loads exposethe electric motor to high starting torque and electrical current surges that are up to eight times the full-load motor current. When VFDdrives are used on an electric motor, the VFDgradually ramps the electric motor up to full load operating speed; this decreases mechanical and electrical stress, which minimizes motor maintenance and motor repair costs which extends the life of the electric motor and manufacturing equipment.VFD drives haveunique programming capabilities that allow for application specific patterns to minimize electrical and mechanical stress on electric motors during operation. Every VFD drive manufacturer uses a unique parameter selection designed so that every manufacturing field has VFD products designed for their industry.

Repair and Replacement

VFD repair should be taken with extreme caution. 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 VFD equipment.Many VFD controllers have an internal DC bus that retains a charge after power has been cut to the drive, as a result, it does not mean it’s safe to work with. Technicians working with VFD repair must always take extra precautions to ensure proper safety measures are taken, or injury or even death may occur.

Precision Electric offers free repair quotes and offers 24 hour emergency repair services. Repair services performed by Precision Electric include anin-service 12 month warranty; the Precision Electric in-service warranty begins the day repaired work is installed and put into service.

To learn more about VFD drives or for VFD repair and replacement, contact Precision Electric.

Eaton power board failure

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This article has been updated and re-posted athttps://www.precision-elec.com/eaton-power-board-failure-2-2/

Eaton power board failure is a common problem among Eaton drive users. The main reason most Eaton drives fail is due to power board or control board failure. Power board failure is usually caused from either Eaton drivesreaching the end of their life cycle orneglecting preventativemaintenance of Eaton equipment. Eaton power boards can be repaired by Eaton Corporation but Eaton takes a long time to diagnose and repair equipment. Most of the time Eaton will hold onto a manufacturer’s drive for months and then tell them that the drive must be replaced because “it isn’t worth repair”. Precision Electric has repaired many Eaton power boards and drives over the years that Eaton deemed “not repairable”.

Eaton power board failure repair services are also offered by Eaton drive distributors but most Eaton drive distributors don’t even repair the drives themselves. Most Eaton drives distributors outsource Eaton drive repair because they don’t have the equipment or technical staff to perform Eaton drive repair Going through an Eaton distributor who is sending the repair to a third party is cost prohibited and takes too long for the drive user. Precision Electric performs all Eaton power board repair in house and offers emergency repair for breakdowns that require immediate service.

The Eaton power board failure repair process should always be taken with extreme caution. Eaton power board failurerepair should only be performed by technicians who have required training and experience to work with electrical equipment. Troubleshooting and repairing an Eaton power board is time consuming and tedious because every Eaton power board can be unique depending upon the Eaton drive functions and capabilities; But, the overall structure of troubleshooting and repairing always remains the same.The ultimate goal when repairing an Eaton power board is to diagnose the cause of failure, repair the power board, and re-commission the unit, as quickly as possible.

Precision Electric performs all Eaton power board failure repairs in house. In house repair ensures efficient turnaround time and repair cost to Eaton drive users. Precision Electric also offers Eaton power board failure emergency repair services for customers who are broke down andrequire immediate repair services.

To learn more about Eaton power board failure or for Eaton power board repair quotes, contactPrecision Electric, Inc.

 

 

 

 

Motor Speed Controllers

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There are three general types of motor speed controllers – AC motor speed controllers, DC Motor motor speed controllers, and Eddy Current motor speed controllers.Eachtype of motor speed controller can be divided into different variations. Each type of motor speed controller system will include an electric motor and aspeed control unit. Motor speed control technology today mainly consists of solid state electronic components in a single system. Older speed controlsystems use mechanical parts that, over time, result in failure due to moving and worn parts.

AC Motor Speed Controllers

AC motor speed controllers are also known as alternating current speed controllers, adjustable speed drives, variable frequency drives, VFD’s, inverters,and micro drives. AC motor speed controllers are used in many applications such as air compressors, conveyors, injection moulding, food processing, wastewater treatment pumps, HVAC fans and blowers, and other industrial applications. Approximately one third of the world’s electrical energy is supplied byelectric motors in fixed-speed centrifugal pump, fan, and air compressor applications. This proves that energy efficiency improvement can be implementedwhere electric motors are operating without speed AC motor speed controllers.

DC Motor Speed Controllers

DC Motor Speed Controllers are also known as DC variable frequency drives, or DC drive systems. The speed of a DC motor is directly proportional to armature voltage and inverselyproportional to motor flux; either armature voltage or field current can be used to control the motor speed. DC Motors have become expensive and todaymost dc motor speed control systems have been retrofitted by pairing an AC motor with an AC motor speed controller. AC motor speed controllers are moreenergy efficient, less expensive and more available than DC motor speed controllers.

Eddy Current Motor Speed Controllers

Eddy current motor speed controllers are a combination of a fixed speed motor and an eddy current clutch. The clutch contains a fixed speed rotor and anadjustable speed rotor separated by a small air gap. A direct current in a field coil produces a magnetic field that determines the torque transmittedfrom the input to the output rotor. The controller provides closed loop speed regulation by varying the clutch current, allowing the clutch to transmitenough torque to operate at the desired speed. Speed feedback is provided by an integral AC tachometer.

Eddy current controllers are less efficient than all other types of motorspeed controllers. Nearly all eddy current controllers are obsolete today.Somemanufacturers still use eddy current motor speed controllers, but when the equipment fails, it’s expensive to repair and oftenimpossible to replace. Eddy current motor speed controllers are upgraded via replacement by pairing an AC motor with an AC motor speed controller.

For motor speed controller replacement, repair, or retrofit quotes, Contact Precision Electric, Inc.

The SMVector Series drive is one of the most cost effective and versatile choices for controlling your motors start and stop method.

6 Step Basic Setup Of An SMV Variable Frequency Drive

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The SMVector Series drive is one of the most cost effective and versatile choices for controlling your motors start and stop method.

If you want complete control over every aspect of your motor, we recommend the SMVector Series variable frequency drive.

The SMVector Variable Frequency Drive is our product of choice for the majority of customer’s applications. There are a number of factors that make us consider it the best option in the market today. One reason it that it’s extremely cost effective compared to many of their competitors. The SMVector Variable Frequency Drives comes in sometimes 20% to 50% less expensive than their counterparts. Another reason to consider the SMVector Variable Frequency Drive is the ease of setup.

This post aims to show the basic setup and configuration of an SMVector Variable Frequency Drive.

1. Turn Off All Line Power

SMVector Variable Frequency Drives come in four different voltages: 120 VAC, 240 VAC, 480 VAC and 600 VAC. No matter what voltage you have it is extremely important to shut off all power prior to wiring your drive. This is extremely important to avoid injury or death. If you are umcomfortable working with these voltages we also recommend hiring a licensed contractor to do the installation for you.

2. Wire The Input Line Voltage

The second step for the basic setup of an SMVector Variable Frequency Drive is the wiring of the input line voltage. Here is a basic overview of the different wiring options for the SMV drive. If you’re running single phase, you may also benefit from reading up on how the SMVector will can be used To Run A 3 Phase Motor On Single Phase Power.

  • Single Phase, 120 VAC: Wire and fuse your hot wire to L1 and wire your neutral to N.
  • Single Phase, 240 VAC (two hot lines): Wire and fuse your two hot lines to L1 and L2 respectively.
  • Single Phase, 240 VAC (one hot line): Wire and fuse your hot line to L1 and wire your neutral to L2.
  • Three Phase, 240 VAC: Individually wire and fuse all three hot lines to L1, L2 and L3 respectively.
  • Three Phase, 480 VAC: Individually wire and fuse all three hot lines to L1, L2 and L3 respectively.
  • Three Phase, 600 VAC: Individually wire and fuse all three hot lines to L1, L2 and L3 respectively.

You will also want to reference the SMVector manual on page 16 for a diagram of how to wire it. Don’t forget to wire an earth ground to the PE terminal as well.

3. Wire The AC Motor

The SMVector Variable Frequency drive currently only support three phase motors. Wiring the motor is extremely easy as there really is only one way to do it. The reason the SMVector currently only supports three phase motors is because it is typically used in industrial applications where higher horsepower and torque is required.

Simply individually wire your motor leads to U, V and W. Don’t forget to also wire your ground wire to the PE ground terminal on the SMV.

4. Jumper The Drive Enable

For basic setup we will be running the drive directly from the keypad so we will not need any custom wiring to the control terminals. One essential thing we need, however, is to electrically enable the drive by putting in a jumper on the control terminals. In order for the drive to enable on power up place a wire jumper between terminals one and four. For a diagram see page 19 of the SMVector Users Manual.

5. Power Up The Drive

You can now power up the drive once you are confident you have wired everything correctly. On powerup the LED screen should come up for programming. At this point in time the default settings should allow you to simply press the start button on the keypad for the drive to run. If you wish to adjust the speed you can use the up and down arrows on the keypad.

6. Finish Your Setup

There are some essential parameters you should set in your SMVector to protect the motor and the drive. See them below, you will want to reference the SMVector Variable Frequency Drive operators manual when doing this. If prompted for the password when entering the parameter menu (by pressing the menu button) then you’ll need to use the arrow keys to enter the default password of 0225.

Set the following parameters to complete your setup:

  • P102 – Minimum Frequency (Speed)
  • P103 – Maximum Frequency (Speed)
  • P104 – Acceleration
  • P105 – Decleration
  • P108 – Motor Overload (Important for Motor Protection)
  • P110 – Start Method (If you want to start on power up)
  • P111 – Stop Method (If you want to coast or ramp to stop)
  • P112 – Rotation (If you want to change direction)

Conclusion:

The SMVector is capable of very advanced features including sensorless vector control and a full range of control terminal options. If you purchased your drive from us then we strongly recommend contacting us if you have any questions or concerns regarding this drive. We are also capable of Variable Frequency Drive Repairwhich includesrepairing them or determining if they are worth repair. You can get a free quotation by contacting us as well.

Preventive Maintenance VFD

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A VFD (variable frequency drive) controls the speed, torque and direction of an induction motor. A VFD takes fixed motor voltage and AC frequency and converts it to a variable voltage and frequency AC output. In very small VFDs, a single power pack unit may contain the converter and inverter modules. Preventive maintenance VFD programs preventmanufacturing downtime while maintaining optimal production performance.

Clean Environment– Preventive Maintenance VFD:

Most VFDs fall into the NEMA 1 category or NEMA 12 category. Drives that fall in the NEMA 1 category are susceptible to dust contamination. Dust on VFD hardware can cause a lack of airflow resulting in diminished performance from heat sink and circulating fans. Dust on an electronic device can cause malfunction or even failure. Dust absorbs moisture, which also contributes to failure. Periodically spraying air through the heat sink fan is a good PM measure. Discharging compressed air into a VFD is a viable option in some environments, but typical plant air contains oil and water. To use compressed air for cooling, you must use air that is oil-free and dry or you are likely to do more harm than good. A non-static generating spray or a reverse-operated ESD vacuum will reduce static build-up. Common plastics are prime generators of static electricity. The material in ESD vacuum cases and fans is a special, non-static generating plastic. These vacuums, and cans of non-static generating compressed air, are available through companies that specialize in static control equipment.

Control boards and other electronic components can be damaged when subjected to periodic moisture or water. Some VFD manufacturers include a type of condensation protection on certain product versions. If you operate a VFD all day every day, the normal radiant heat from the heat sink should prevent condensation. Unless the unit is in continuous operation, use a NEMA 12 enclosure and thermostatically controlled space heater where condensation is likely.

Keep Connections Tight – Preventive Maintenance VFD:

Checking connections is a step many people miss or do incorrectly, and the requirement applies even in clean rooms. Heat cycles and mechanical vibration can lead to sub-standard connections, as can standard PM practices. Reusing torque screws is not a good Idea, and further tightening an already tight connection can ruin the connection.

Bad connections eventually lead to arcing. Arcing at the VFD input could result in nuisance over voltage faults, clearing of input fuses, or damage to protective components. Arcing at the VFD output could result in over-current faults or even damage to the power components.

Loose connections can cause erratic operation. For example, a loose START/STOP signal wire can cause uncontrollable VFD starting and stopping. A loose speed reference wire can cause the drive speed to fluctuate, resulting in scrap, machine damage, or personnel injury.

Additional Considerations – Preventive Maintenance VFD:

  • As part of a mechanical inspection procedure, don’t overlook internal VFD components.
  • Check circulating fans for signs of bearing failure or foreign objects.
  • Store spare VFDs in a clean, dry environment, with no condensation allowed.
  • Power spare VFD’s every 6 months to keep the DC bus capacitors at their peak performance capability.
  • Regularly monitor heat sink temperatures.
  • Inspect DC bus capacitors for bulging and leakage. Either could be a sign of component stress or electrical misuse.

You wouldn’t place alaptop computer on the roof of a building or in direct sunlight, where temperatures could reach 115 degrees Fahrenheit or as low as -10 degrees Fahrenheit. A VFD, which is basically a computer with a power supply, needs the same consideration. Some VFD manufacturers advertise 200,000 hours-almost 23 years-of Mean Time between Failures (MTBF). Such impressive performance is easy to obtain, if you follow these simple procedures.

By integrating a preventive maintenance VFD program, you can ensure your drives provide minimal repair service while maximizing production.Always call certified variable frequency drive integrators or experienced technicians to perform preventive maintenance VFD services to prevent injury or death.

To learn more about preventive maintenance VFD programs or for VFD repair and replacement quotes, contact Precision Electric.