The Official Variable Frequency Drive (VFD) Distributing Blog

Machinery imported into the United States is often rated at an operating frequency of 50 Hertz.  Unless engineered for operation at 60 Hz., this can be problematic for electric motors. This is especially true when operating pump and fan loads.  Too often the distributors and purchasers of this machinery assume that the Original Equipment Manufacturer [...]

Many electricians apply Variable Frequency Drives (VFDs) to AC Motors that are not inverter rated. Many are not even aware that inverter rated motors exist.
Inverter rated motors are not required for inverter applications, however, when a VFD is applied to an inverter rated motor, the inverter rated motor has less chance of premature winding failure. Inverter rated motors have [...]

A properly applied Variable Frequency Drive (VFD) will significantly reduce operating costs.  This is particularly true for variable torque loads such as:

Fans
Blowers
Pumps 

Blowers, for example, are often used with dampers to control air flow.  These dampers may be operated either manually or automatically.  When dampers are closed, 50% motor current will drop to approximately 60% of Full Load [...]

One of the more common problems seen in our Variable Frequency Drive (VFD) repair division is the failure of the IGBT (Insulated Gate Bi-polar Transistor) power section modules. 
If the Variable Frequency Drive (VFD) is blowing fuses, or the VFD simply is not turning on, the following test may aid you in finding the root of the problem.
A digital voltmeter test can tell if a [...]

Engineering technicians have many nightmare stories when it comes to on-site troubleshooting.  In this instance, I was called to help troubleshoot a Closed Loop (Sensorless Vector) Variable Frequency Drive (VFD) on a production line that was so large, it seemed to go so far down the plant, it never ended. 
After overcoming the intimidation associated with the sheer size of the line, it became a question of [...]

Often times those using a Variable Frequency Drive (VFD) may find themselves needing to connect a higher horsepower VFD to a single phase input power source.  Since most higher horsepower VFDs only accept three phase input as a power source, they are left with little options or alternatives. Don’t fret, there is a solution.
If you are using a Variable Frequency Drive (VFD) rated for [...]

If you do not yet know how a Variable Frequency Drive (VFD) works, it is recommended you visit our post entitled: How Does A Variable Frequency Drive (VFD) Work? prior to reading this post.
AC Three Phase Induction Motor RPM is determined by the formula:

RPM = (120 * Frequency) / # of poles in the motor

Since [...]

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: 

Alternating Current (AC) power is applied to the input of the VFD and feeds a bridge rectifier.
The rectifier converts the Alternating Current (AC) voltage [...]

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 [...]

Variable Frequency Drives (VFDs) are electronic devices used to control the speed of an Alternating Current Motor (AC Motor).  Variable Frequency Drives (VFDs) are also commonly known as adjustable frequency drives, adjustable speed drives, AC drives and inverters.
Variable Frequency Drives (VFDs) have a wide range of application use that include, but are not limited too:

Variable Air Volume Systems
Circulating [...]