VFD Buying Guide

General pointers before buying a VFD

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When applying a Variable Frequency Drive  to a new or existing application there are many factors to consider prior to making a firm decision on what type of VFD should be used. If one already has an existing application where VFD’s 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 an appropriate solution for your application is.

There are a several different types of Variable Frequency Drives and 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 some 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:

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V/Hz (Volts per Hertz) Variable Frequency Drives (VFD’s)

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This is the most commonly used and most basic VFD available and is designed for rather basic applications 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 VFD’s in this class have adequate programming features for many applications.  Be certain that adequate I/O’s and programming features are available to meet your application requirements.

This product is also an inexpensive alternative to a phase converter since they will accept single phase input while providing three phase output.

For this type of application we have for you the brand new and impressively featured VLT Micro or DANFOSS FC-51 series. Please download the FC-51 Procuct Brochure plus the FC-51 Programming Guide for your further review.

Alternatively you could opt for the amazingly robust VLT-2800 series. Its performance is tested and proven with several years of reliable serrvice and some of our most nameful customers do count on this models.

Please download the VLT-2800 Catalogue plus the VLT-2800 Programming Guide for your further review.

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Sensorless (Open Loop) Vector Variable Frequency Drives (VFD’s)

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The next VFD type which is commonly used for example in a lathe, at a mill or at any other application where full torque is required throughout the motor speed range.

Sensorless Vector VFD’s 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.

However, if speed feedback and/or extremely complex programming must be considered in your application you cannot use a sensorless Vector VFD anymore.

Sensorless Vector/Open Loop Vector VFD’s do offer complex programming to a certain degree, but when your application exceeds sensorless vector programming features, there is a third solution:

For this type of application we do recommend the DANFOSS FC-301 series. We call it also the Automation Drive and we do that for good reasons.

Please download the FC-300 Brochure plus the FC-300 Programming Guide for your further review.

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Closed Loop Vector Variable Frequency Drives (VFD’s)

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This next level of VFD’s is 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 really phenomenal.  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 such as Gingoog Electric Trading (G.E.T.) 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.

This is a perfectly clear job for the cousin of the above mentioned FC-301, our most sophisticated series, the DANFOSS FC-302 series which is another Automation Drive but with the necessary added features and capabilities.

Check how FC-301 and FC-302 compare with the same FC-300 Brochure and have another look on the FC-300 Programming Guide.

For larger ratings we would like to refer to our VLT High Power Drives with the FC-300 High Power Brochure and the FC-300 High Power Manual

If not downloaded and reviewed already earlier we would like to use this opportunity to recommend having an eye on some General Facts of VFD’s, particularly also on some Danfoss Drive Facts and to round it up probably also the Danfoss VFD Overview.

Another overview is also available at the download section of our Danfoss VFD Page.

Let us know when you have more specific questions and we will be glad to respond to your inquiry right away. Simply use our GET Contact Form.

Ralf Wabersich

Gingoog Electric Trading (G.E.T.)

More about VLT’s

More about Danfoss VLT Drives

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In our previous articles we embedded already some short videos, hence we hope that your computer has the necessary flash player installed so that you can view them but if not you could click the corresponding link to get the free download of the latest flash player version because at the buttom of this we will provide another video which shows in a few very well illustrated ways what VLT is all about.

Although our latest blog articles could be viewed also at the blog part of our Home Page but technical reasons do not allow it to see the videos there. They run only on our original GET Blog, so please be advised accordingly.

Very interesting insights about AC motors and Frequency Converters in general plus some protection and safety aspects together with some more related theories could be also found in our VFD Facts file while more particular introductions abour our VLT family could be viewed in our Danfoss VFD Overview, both a must see for those who really want to know more about this topic.

Just click the tile of the file you want to have or take a right click, followed by “Save Target As” or simply hit the provided download link at the top of the tile, after one or two downloads we are sure that you got already very familiar with the way it works.

Feel free to browse also other related files stored at our Sky Drive section in this blog and save them on your hard disk for easy, convenient and quick access anytime.

For the meantime though enough words and enough files, lets go now to the video below and enjoy the show.

Have a great time.

Ralf Wabersich

Gingoog Electric Trading (G.E.T.)

More about VFD’s

More about Variable Frequency Drives but why Danfoss?

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In our first technical blog entry a few days ago we spoke already in the category GET Savings about some of the benefits of Variable Frequency Drives or in short VFD’s and aside from the utmost flexibilities at minimal space, full control and protection, reliable performance and safety features we found out together with the support of a very relevant presentation that we can save indeed a lot and I mean really a lot, not only in terms of energy but also in other maintenance and operation expenses.

The return of such an investment, or ROI, is usually achieved after 12 to 18 months already, depending on the particular model selected, the type of application and of course the average runtime and this is actually also about the warranty period granted to such a unit, one whole year that is to be exact… Another too good to be true? Again, it is good and it is true.

OK, now we know that VFD’s are great stuff but why should we GET Danfoss and no other brand?

The reasons here are as versatile as our products itself and while we will surely go more into product details as we progress I believe this is a very good opportunity already to highlight just a few general Danfoss features such as for example:

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1.) Its user-friendlyness with an awardwinning control panel:

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This key pad was actually created by a Nokia designer and equipped with a very intuitive parameter structure, so the programming and scrolling trough the menus can be truly compared to the rather simple handling a cell phone, meaning something we actually all do on a daily basis and are more than familiar with.

Our so called Quick Menu, an ideal short menu version for regular standard applications makes the commissioning even additionally easier, faster and safer with very minimal to non manual reading required.

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2.) Its exceptional and remarkable quality and reliability:

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Danfoss uses only highest quality components and genuine VLT solutions, two of the very reasons why our products are certified with ISO 9001 standard.

All models use an intelligent heat management which removes the process heat through a very effective heat sink or through forced convection cooling wherein a fan blows cold air through the cooling ribs of the aluminium base.

This systems are highly efficient and allow operations at an ambient temperature of up to 50 degrees Celsius but this systems also leave the electronic parts protected from dust and dirt because no air flows through its compartments.

Now this is only one of our ways to protect the electronics of your Danfoss Drives but this is not all, we do more because all our models come with silicon coated circuit boards.

Yes, that is right, all electronics are coated already as standard, meaning those little dust particals which can possibly still come in over a longer period of time could even in combination with tropical moist from our natural humid environment, hence the lifespan of all our products is dramatically increased and this is exactly what all our customers do confirm just as well.

Throughout the years we have really observed that Danfoss simply outlasts other available brands in our area and our satisfied customers know why they GET the VFD’s from GET.

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3.) Its noteworthy high performance:

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Danfoss Drives are all designed to perform perfectly even in rather complex application set-ups. A huge number of parameters in the advanced mode can be set to optimize the energy efficiency for example with the built in Automatic Energy Optimizer or AEO.

To optimize the operation itself we have as another example a build in Process PI Controller and Smart logic Controller which could eliminate the very need of any external controller or make an additional Programmable Logic Controller or PLC ommissible, that’s how smart our Drives nowadays really are, we offer only the latest technology in our product range.

Built in Electronic Thermal relays or ETR’s replace the conventional external motor protection, other features to be mentioned are Torque Boost, Automatic Motor Adaption or AMA for less energy consumption, Flying Start with which you could even catch an already or still spinning motor for a lean operation and more uptime,.

RFI filters at the input and the output to eliminate emission and to achieve immunity and both sided Harmonic Filers, Kinetic Backup, Dynamic Braking, Sinewave Filters, various Serial Communication features, completely water and dust proofed rated enclosures, etc, etc, etc… the list is long but eventually we will come to all of that.

For the meantime I have prepared here some more general Facts about Drives and a quick VFD Overview for you guys and I hope you enjoy the reading.

VFD’s can really do much more than commonly known and really do deserve to be studdied more, they are truly a vital component in all of your automation requirements.

However, and also here we will definitely still dig much deeper into the issue but I would like to mention already today that we also carry Danfoss Softstarters, a perfect replacement to the conventional Star-Delta setup which requires at least 3 well rated contactors and if not completely manually operated also an additional timer plus of course overload relays, other desired protective devices and possible control gadgets.

All of this belongs to the past and the proper solution here would be a good Danfoss Softstarter. I prepared also here already some general views on the matter in this Softstarter Presentation.

Have a great day!

Ralf Wabersich

Gingoog Electric Trading (G.E.T.)