Variable frequency drive torque control inverter vfd

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Customers of Precision Electric have been using variable frequency drives to better control torque on electric motor applications for a number of years. This posting is to help you decide what type of variable frequency drive will work best for your application.

For a new VFD application:

  • Research the motor andVFD specifications.
  • Research yourapplication requirements.
  • Learn more abouttheVFD products that are available to you.
  • Understand thefeatures of thoseVFD products to determinewhatis an appropriate solutionfor yourapplication.

There are a several different types of Variable Frequency Drives. The following is a short summary ofthe three different types of drives 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 VFDavailable; this product is for a basic applicationinpumps, fans, conveyors, blowers and others. These applicationsdo not require high starting torque, full motor torque at low rpm, and/or speed feedback. Most V/Hz VFDshave adequate programming features for many applications. Be certain adequate I/O and programming features are available to meet your application requirements. This product is an inexpensive alternative to a phase converter since they will acceptsingle phase input while providingthree phase output.

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

The next VFDtype that is commonly used in a lathe, mill or any applicationwhere full torque is require throughout the motor speed range.Sensorless Vector VFDsareare also referred toas open loop vector drives; these drives are morecomplex than V/Hz drives and should always be applied to applicationswhere high starting torque and/or full torque operating at lowRPM is required. If speed feedback and/or extremely complex programming must be considered in your applicationyouCANNOT use a sensorless vector VFD. Sensorlessvector/open-loop vector VFDsdo offer complex programming to a certain degree, but when your applicationexceeds sensorless vectorprogramming features, there is a third solution.

Closed Loop Vector Variable Frequency Drives (VFDs)

This next level of VFDsare more advanced. Applicationsthat require accurate speed regulation and feedback from the motor and/or require complex programming will require a closed-loop vector drive. Thistype of VFDis 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, advancedmanufacturing facilitiesacrossthe world, closed-loop vector technology has few limitsin drive technology. The product features are phenomenal. Applicationswhere these products are utilized provide superior speed regulation and torque performance.

Before choosing a drivefor your applicationconsult with a qualified integrator, distributor, or manufacturer who will ask all the right questions and make an appropriate recommendation. Here at Precision Electric Inc we offer proper service and telephone support from when you, or your qualified electrician, are setting up the drive for your application. Call us today.

Ryan Chamberlin
Inside Sales, Customer Support
[email protected]
Call Toll Free: 1.877.625.2402