FAQ :: VFDs | How Do I Pick A Variable Frequency Drive for My Application?

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When applying a Variable Frequency Drive (VFD) to a new or existing application there are many factors to consider prior to making a firm decision on what type of Variable Frequency Drive (VFD) should be used. If one already has an existing application where VFDs seem to consistently fail, they should look to using a different VFD type for potential success. For a new VFD application one should:

  • Research the motor and VFD specifications.
  • Research your application requirements.
  • Learn more about the VFD products that are available to you.
  • Understand the features of those VFD products to determine what is an appropriate solution for your application.

There are a several different types of Variable Frequency Drives (VFDs). Not all drive manufacturers offer every type of VFD available in the market. So if one has their heart set on a specific product line, one must first do research to ensure the desired manufacturer offers the type of VFD needed by the application. The following is a short summary of the three different types of VFDs that are available and when these types of drives should be considered in an application:

V/Hz (Volts per Hertz) Variable Frequency Drives (VFDs)

The most commonly used and most basic VFD available; this product is for a basic application in pumps, fans, conveyors, blowers and others.  These applications do not require high starting torque, full motor torque at low rpm, and/or speed feedback.  Most V/Hz VFDs have adequate programming features for manyapplications.  Be certain adequate I/O and programming features are available to meet your applicationrequirements.  This product is an inexpensive alternative to a phase converter since they will accept single phase input while providing three phase output.

Sensorless (Open Loop) Vector Variable Frequency Drives (VFDs)

The next VFD type that is commonly used in a lathe, mill or any application where full torque is require throughout the motor speed range. Sensorless Vector VFDs are are also referred to as open loop vector drives; these drives are more complex than V/Hz drives and should always be applied to applications where high starting torque and/or full torque operating at low RPM is required. If speed feedback and/or extremely complex programming must be considered in your application you CANNOT use a sensorless vector VFD. Sensorless vector/open-loop vector VFDs do offer complex programming to a certain degree, but when your application exceeds sensorless vector programming features, there is a third solution.

Closed Loop Vector Variable Frequency Drives (VFDs)

This next level of VFDs are more advanced. Applications that require accurate speed regulation and feedback from the motor and/or require complex programming will require a closed-loop vector drive. This type of VFD is often offered as a “three in one” and able to operate in all operating modes.

  • V / Hz (Volts per Hertz)
  • Sensorless (Open Loop) Vector and
  • Closed Loop Vector

These products are complex and extremely efficient when properly applied. Used in the most complex, advanced manufacturing facilities across the world, closed-loop vector technology has few limits in drive technology. The product features are phenominal.  Applications where these products are utilized provide superior speed regulation and torque performance.

Before choosing a VFD for your application consult with a qualified integrator, distributor, or manufacturer who will ask all the right questions and make an appropriate recommendation.  Be sure you will be able to get proper service and telephone support from them when you, or your qualified electrician, are setting up the drive for your application.

VFD for pumps energy‑savings example

VFD for Pumps: Benefits, Setup & Best Practices

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Estimated reading time: 5 minutes

Installing a VFD for pumps in an industrial facility is no longer optional; it is the fastest way to cut electricity costs and stabilize production. Because pumps rarely need to run at full speed all day, engineers now choose speed control instead of throttle valves. Consequently, energy waste disappears and equipment lasts longer. Moreover, the International Energy Agency lists pump systems as the number‑one target for industrial efficiency programmes, which means rebates are often available.

Therefore, plant managers who invest in a modern pump VFD quickly recover the capital outlay, typically in less than two years. Another benefit is operational transparency: many smart drives stream real‑time data to SCADA dashboards, so maintenance teams see power, flow and fault codes at a glance. In addition, soft‑start and soft‑stop profiles eliminate pressure hammer and reduce seal wear.

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Difference between Eaton SVX9000 and SPX9000 adjustable speed drives

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The difference between Eaton SVX9000 and SPX9000? Many Eaton customers call or email asking “what is the difference between Eaton SVX9000 and SPX9000?” There is only a small difference between the two drives other than a letter and the price. The difference between Eaton SVX9000 and SPX9000 is that the SPX9000 is used for applications with speed feedback and the SVX9000 is used on general purpose applications that do not need speed feedback.

Eaton’s SVX9000 adjustable frequency drive has sensorless vector control technology coupled with an adaptive motor model and sophisticated ASIC circuit. Sensorless vector technology allows for steady speed error, fast torque rise time, high immunity to resonance vibrations and high starting torque and current. The SVX9000 is suitable for multiple motor drive systems and high-speed applications.

The SVX9000 Series Adjustable Frequency Drives are specifically engineered for today’s commercial and industrial applications. These drives continue the tradition of robust performance, and raise the bar on features and functionality, ensuring the best solution at the right price. SVX9000 Features include: Startup Wizard, seven built-in applications, local/remote button, modular design, text display, and the following:

  • Ease of use: Startup Wizard, seven built-in applications, local/remote button, modular design, text display
  • Space-saving design: Compact design, open NEMA12 option, onboard I/O expansion provisions
  • Efficiency: Built-in 3% line reactor, EMI/RFI filter standard
  • Rugged and reliable: High overload (CT) and low overload (VT) rated, robust time-proven design, durable metal power section, brake chopper circuit.

SPX9000: difference between Eaton SVX9000 and SPX9000

Eaton’s SPX9000 drives are designed specifically for high-performance applications. They feature high processing power and the ability to use information from an encoder or a resolver to provide precise motor control. In addition, a fast microprocessor provides high dynamic performance for applications where good motor handling and reliability are required.

  • Sensorless vector and simple frequency control are supported.
  • The drives can be used in both open loop applications and in applications that require encoder feedback.
  • The SPX9000 supports fast drive-to-drive communication and an integrated data logger functionality.
  • Simultaneous fast monitoring of several drives can be done using the 9000X drive tool and CAN communications.

The main difference from the two products is that the SPX9000 can run motors with speed feedback (i.e. encoder or tachometer). The SVX9000 does not have the ability to run a motor with speed feedback. So if the application requires speed feedback, SPX9000 is the solution. If no speed feedback is needed, the SVX9000 is the solution.

To learn more about Eaton drives, visit the Eaton Website. For Eaton Repair and Replacement quotes, contact Precision Electric.

CNC Machining & Dynamic Braking with High Frequency Output Inverter Applications 0-400hz

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We often receive inquiries for variable frequency drives that are capable of high frequency output. Spindle applications such as CNC equipment generally use a high frequency output, up to 400Hz.

Customers often have trouble locating the proper product for these applications. Precision Electric offers a few different options for these type of applications. Our number one recommended product for high frequency output applications is the Lenze/AC Tech SMV Drive.

The SMV drive is designed for several types of applications, including high frequency output. The standard maximum output on many variable frequency drives is 60 -120 hz. The Lenze/AC Tech SMV has capabilities from 0-400hz, right out of the box. We also offer other Lenze/AC Tech products that have a high frequency output option; such as the Lenze/AC Tech MC series and Lenze/AC Tech SCF series drives. However, if you need either an SCF or MC series drive with high frequency output, you must specify that you need the high frequency option. The SCF and MC series products do not come factory equipped with the high frequency option unless specified when your order is placed.

Machine Tool applications such as the spindle on a CNC machine often run their equipment off of high frequency inverters. Typically dynamic braking kits are required when using high frequency output on this equipment.

When CNC machines are running at high speeds the inertia of the spindle causes the motor to become a generator once the stop button is engaged. Voltage generated from the motor goes back onto the DC bus in the drive. This often will cause the drive to trip on an “over bus fault”. This problem is addresed by adding a dynamic brake kit to the drive. The dynamic brake switch will turn on when the bus voltage reaches a preset level to disapate this excess energy across a set of resistors. This will prevent the drive from faulting. The required resistor wattage is determined by the inertia of the load and often requires more wattage than a standard dynamic brake kit will offer. The expert sales staff at Precision Electric will assist you when selecting a drive/brake package for these applications.

Ryan Chamberlin
Inside Sales, Customer Support
[email protected]

Technician programming VFD controllers panel for conveyor line

VFD Controllers: The Practical Buying Guide for Industrial Users

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Electric‑motor driven systems consume almost half of the world’s electricity, and in manufacturing the share can exceed 70 %. Because many motors still run at full speed even when the process does not require it, untapped efficiency remains enormous. VFD controllers — also known as variable speed drives, AC drives, drive inverters or motor drives — solve that problem by regulating motor frequency and voltage in real‑time so that the machine draws only the power it genuinely needs. According to Efficiency Vermont, trimming a centrifugal fan’s speed by just 10 % cuts energy use roughly 25 %.

The savings grow exponentially, and when paired with soft‑start, diagnostics and smoother process control the business case is formidable. This article summarises the latest manufacturer documentation, standards and peer‑reviewed research, then turns those findings into a clear buying workflow. For deeper background, see our cornerstone resource Variable Frequency Drives – Benefits, Sizing & Products or explore the types of variable frequency drives in greater detail. Meanwhile, keep reading to discover how the right VFD will reduce operating costs, lengthen equipment life and improve product quality.

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Motor and VFD setup for autotune

VFD Auto tune: Setup, Troubleshooting & Best Practices

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Estimated reading time: 11 minutes

Variable Frequency Drives (VFDs) are widely used to control motor speed and torque in industrial and commercial applications. However, to get the best performance from a VFD, you must take advantage of its VFD auto tune feature. Skipping or misusing this critical VFD auto tune step can lead to inefficient operation, poor torque control, or even nuisance trips.

In this article, we’ll explain what VFD auto tune is, why it’s important, common auto tune issues and their solutions, and how to properly perform an auto tune. By the end, you’ll know how to optimize your drive for smooth, reliable operation.

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Variable Frequency Drive Basics

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Variable frequency drives are also known as (VFDs), variable speed drives (VSDs), adjustable speed drives, and inverters. Variable frequency drives are solid state controllers used in AC or DC electric motor applications. Most variable frequency 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 often fail.  Variable frequency drives can also be used as a phase converters when three phase motors need to be operated from single phase power.

Variable frequency drives can be used in small appliances, large mills, lathes, air compressors, conveyors, and many other electric motor applications in the industrial manufacturing world. 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 variable frequency drive on mills, air compressors, and fans is to reduce the amount of electrical energy being consumed which consequently reduces electricity costs on unused power.

Energy Savings

About 3% of the total installed AC electric motors in the United States use variable frequency drives. 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 variable frequency drives on these electric motor applications.

Performance and Operation

Variable frequency drives are applied to alternating current (AC) electric motors to increase quality control in manufacturing processes in the industrial manufacturing world. Variable frequency drives increase quality control in the industrial manufacturing world via monitoring the electric motors’ speed, pressure, temperature, torque, and tension.

Fixed-speed electric motor loads subject the electric motor to a high starting torque and electrical current surges that are up to eight times the full-load motor current. When a variable frequency drive is used on an electric motor, the variable frequency drive gradually ramps the electric motor up to full load operating speed, and this decreases mechanical and electrical stress, which minimizes motor maintenance and motor repair costs which ultimately, extends the life of the electric motor and manufacturing equipment.

Variable frequency drives’ unique programming capabilities allow for application specific patterns to minimize electrical and mechanical stress on the electric motors’ they’re operating. Every variable frequency drive manufacturer uses a unique parameter selection designed so that every manufacturing facility can seek out the product designed for their industry.

Repair and Replacement

The internet has brought high demand of quality repair processes and competitive pricing in the industrial manufacturing world. Maintenance technicians began seeking alternative solutions via the internet for their need of variable frequency drive repair and replacement because maintenance technicians do not always receive the services needed to be a leader in their industry.

A highly trained repair facility is the backbone of successful production.  Precision Electric has been repairing industrial electronics, rewinding electric motors, and servicing all other industrial-related equipment since 1982. Customers on the coasts of the United States send Precision Electric repair work everyday such as variable frequency drives, servo motors, servo drives, encoders, printed circuit boards, electric motors, and all other related equipment.

Precision Electric offers free quotes for all repair work and has a reputation for keeping manufacturers’ downtime to an absolute minimum while increasing production processes for 30 years. Equipment repaired by Precision Electric is more reliable than brand new equipment purchased from the manufacturer, because Precision Electric uses the most advanced testing equipment and replaces generic components with the best components in the industry. Precision Electric offers an in-service warranty on all repair work completed. The Precision Electric in-service warranty begins the day repaired work is put into service and ends 12 months thereafter.

Eaton VFD M

Eaton VFD Motor Drives

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Eaton VFD motor drives can reduce energy consumption in factories from 10 to 50 percent. Technicians achieve this energy reduction through motor speed reduction. Since most equipment does not require the full load motor speed for effective production, an electric motor’s needed output speed is reduced via Eaton VFD motor drives. Reduced energy consumption lowers utility expenses  and in some cases, the investment of Eaton VFD motor drives quickly pay for themselves.

The DG1 general-purpose Eaton VFD motor drives are part of the PowerXL series. The DG1 is specifically engineered for today’s more demanding commercial and industrial applications. Eaton DG1 drives offer an industry-leading energy efficiency algorithm, high short-circuit current rating, safety, and reliability. The LCX9000 drive is liquid-cooled to utilize potable water or a water-glycol mixture as a cooling medium. The LCX9000 drive has a compact size and low heat transfer rates to allow the enclosure size to be greatly reduced, which is especially beneficial in UL Type 4X applications.

The CFX9000 clean power Eaton VFD motor drives use tuned passive filters to significantly reduce line harmonics at the drive input terminals. These drives are ideal for small to midsize applications where harmonics are problematic. The CPX9000 drives are used for pump, waste water, HVAC, industrial and process industries, where harmonics are present. They offer one of the purest sinusoidal wave forms available in the VFD market.

The SVX9000 Eaton drive offers sensor-less vector technology with an adaptive motor model and sophisticated ASIC circuit. This technology allows for steady speed error, fast torque rise time, high immunity to resonance vibrations and high starting torque and current. The SVX9000 is suitable for multiple motor drive systems and high-speed applications.

Eaton VFD Motor Drives That Are Obsolete

The SLX9000 Eaton VFD motor drives are compact, powerful and are based on the more robust SVX9000. The SVX9000 is a newer version of the obsolete SLX9000. It is designed to be the next generation of drives specifically engineered for modern commercial and light industrial applications. Eaton MVX9000 series drives are obsolete and replaced by Eaton M-MAX drives. The M-Max drive is a compact micro drive with a broad power range. Typical applications for the M-Max include Food and Beverage, HVAC, Packaging, Pumping, Textile, OEM, and more.

The HVX Eaton VFD motor drives are replaced by the Eaton H-MAX drives. The H-MAX series 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 variable frequency drive needs.

For more information on Eaton VFD motor drives, visit the Eaton Website. For Eaton VFD motor drives repair and replacement quotes, Contact Precision Electric.

FAQ :: VFDs | How Does A Variable Frequency Drive Work?

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An AC Variable Frequency Drive (VFD) is commonly referred to as an “Inverter”. This is because of the way a VFD works.  The following details the inner workings of a VFD:

  1. Alternating Current (AC) power is applied to the input of the VFD and feeds a bridge rectifier.
  2. The rectifier converts the Alternating Current (AC) voltage into Direct Current (DC) voltage.
  3. The Direct Current (DC) voltage then feeds the Direct Current (DC) buss capacitors on the VFD where it is stored for use by a transistor or Insulated-Gate Bipolar Transistor (IGBT).
  4. Direct Current (DC) from the capacitors feed the input of the transistor(s).
  5. The transistor(s) then continuously turns on and off at the appropriate frequency to build a new sine wave for use by the motor connected to the output of the VFD.

The process above is often referred to as inversion because it changes from one form to another then back again.

The voltage frequency, as distributed in the USA, is 60 cycles per second and the unit of measurement is Hertz (Hz). The output frequency and voltage of an AC Variable Frequency Drive (VFD) is variable and controlled by the speed at which the output transistor is continuously turned on and off.

The variable speed is controlled digitally in modern VFDs and changed by the operator through programming, an operator interface, or by changing an analog input to the VFD that is programmed as “speed reference input”.

 

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 prevent manufacturing 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 VFD’s 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 a laptop 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.

Nema Cabinet Ratings: Protecting a VFD from environmental conditions

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Nema cabinet ratings are designed to protect electrical components from environment-specific threatening conditions. Nema cabinet ratings are made for a range of different environmental conditions. There are as many Nema cabinet ratings available as there are environmental conditions where equipment is installed.

VFD manufacturers will usually offer variable frequency drive (VFD) products in several different Nema cabinet ratings to cover a broad range of customer needs. It’s important to choose the right Nema cabinet ratings for your VFD because: A.) you don’t want your VFD to fail because then your operation is down / production is disrupted; and, B.) VFD warranty is often voided due to choosing the incorrect Nema cabinet ratings of VFD.

While there are a variety of Nema cabinet ratings available, the Type 1, 12, 3R, 3RX, 4, and 4X are specifically used in the Food and Beverage industry and HVAC industry. Of those Nema cabinet ratings, the Type 1, 12, and 3R options are used in over 95% of VFD installations. Type 3RX, 4, and 4X enclosures are available for unusually harsh and dusty environments. Whenever practically possible, mount the VFD in a stable environment, such as a mechanical room. Otherwise, make sure the Nema ratings for your VFD are susceptible to the environmental conditions of installation site.

UL Type 1 VFDs

  • Indoor locations only
  • Minimal dirt/dust in the air
  • No exposure to water spray or drips
  • Most common HVAC VFD enclosure

UL Type 12 VFDs

  • Indoor locations only
  • Dirty/dusty environment
  • Possibility to be splashed with water

UL Type 3R VFDs

  • Outdoor location
  • Minimal salt/corrosives in the air
  • Maximum ambient temperature ≤122°F

UL Type 4 VFDs1

  • Indoor or outdoor locations2
  • Requirement to wash-down the VFD
  • Combination of dusty environment with
  • heavy moisture (fog)
  • Properly sized units may operate >122°F

UL Type 4X VFDs1

  • Indoor or outdoor locations2
  • Requirement to wash-down the VFD
  • Significant salt/corrosives in the air
  • Properly sized units may operate >122°F

UL Type 3RX VFDs

  • Identical to Type 3R except with stainless steel box
  • A degree of salt/corrosives in the air
  • enclosure appearance is important

When buying a VFD, make sure the VFD Nema cabinet ratings are susceptible to withstand the environmental conditions of installation site. If you’re unsure which Nema cabinet best fits your application, contact Precision Electric with your application specifications; Precision Electric will provide you with a VFD quote that will meet your enclosure specifications. Call Precision Electric at 574-256-1000 for VFD repair, VFD replacement, or complex VFD project quotes.

 

Credit refs: most of the information in this article was originally published by ABB: LV drives division.

Some information was obtained from the ABB download center. Precision Electric is a certified ABB LV Drives

distributor and ABB Certified Startup Center. Certified Startup improves ABB Factory Warranties on LV Drives.

Additional information can be found at nema.org 

 



Lenze EtherNet/IP for SMVector
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Lenze-AC Tech announces the release of EtherNet/IP as an optional communication protocol for the SMVector Drive. According to Mike Bailey, Product Sales Manager at Lenze-AC Tech, the SMVector AC Drive can seamlessly operate on an EtherNet/IP network with the addition of a simple plug-in communication module. “Other network protocols are also available as option modules including CANopen, DeviceNet, Profibus and Modbus RS-485,” states Bailey.






EtherNet/IP is a member of the DeviceNet and ControlNet family of Common Industrial Protocols (CIP) developed by Allen-Bradley (Rockwell Automation – ROK). As a member of the CIP family, EtherNet/IP can utilize the same set of pre-defined common objects, thus making communication between devices from different manufacturers much easier.


According to Lenze-AC Tech company officials, Lenze-AC Tech worked together with Allen-Bradley engineers to ensure complete product compatibility. “We first added EtherNet/IP to our PositionServo Drive and since then, our customers have been looking for EtherNet/IP for their AC Drive Solutions,” says Bailey, and he adds, “Allen-Bradley remains the largest implementer of EtherNet/IP, with most applications in the packaging and automotive markets; providing Allen-Bradley compatibility and multiple communication options for all of our products allows our customers to choose the fieldbus that best fits their automation application as well as their physical network.” Bailey explains that EtherNet/IP is a popular industrial network solution because it can support a nearly unlimited amount of nodes, can be used on a single point connection for configuration and control and permits devices to send and receive messages simultaneously.




Ryan Chamberlin

Inside Sales, Customer Support

[email protected]