Medium voltage MV ac drives are much larger and produce much more power than smaller and more common low voltage drives.
Consequently, they are found controlling much larger electric motors such as those found in mines, electric utilities, steel mills, water treatment facilities and oil field applications. Since the higher voltages, commonly 4160 volts, allow for less amps, the installations are mechanically easier due to smaller cable sizes.
Medium Voltage MV VFDs must pay attention to harmonic and motor noise mitigation and almost all modern drives do. Here at EMA we most commonly sell the Toshiba T300MVI medium voltage VFD and they have taken great care in this area. Their switching topology, active bus clamping, and other innovations make them one of the least disruptive MV Drives on the market.
Most medium voltage MV VFD applications are variable torque loads, such as pumps and fans. In the past these large motors were started and operated across the line, and since medium voltage MV VFDs were so expensive, the energy savings possible with them wasn’t viable.
However, the cost of medium voltage MV VFDs has dropped considerably as the state of the art has improved. The well known energy saving abilities of VFDs on low voltage fan and pump applications are now applicable to medium voltage MV VFD applications, only more so. We’re seeing paybacks of less than one year in some cases, and this has driven the demand for medium voltage VFDs as never before.
There is another factor driving the application of medium voltage MV VFDs that was seldom seen in low voltage VFDs. Many medium voltage MV VFDs are simply used as starters. This is because with the additional stresses placed on the US power grid, starting a large medium voltage motor is often frowned upon by the power companies. Medium Voltage Soft Starters can sometimes work, but not as often as you might think. Often, the least costly and best solution is to simply use a medium voltage VFD as a starter. (See when you should use a VFD as a soft starter)
Although the majority of Medium Voltage MV VFDs we sell and service are used on centrifugal fan and pump loads, we are seeing more and more on conveyors, gas compressors, and other constant torque loads. In these cases the medium voltage MV VFDs are not being used so much to save energy, as to tightly control a critical process.
Applying, servicing, and installing MV VFDS is not for the inexperienced, although the manufacturers have done a great job in simplifying the product lines.
At EMA, we routinely repair, service, apply, and provide medium voltage MV VFDs all over the United States and world. Call 770-448-4644770-448-4644 or hit any of the contact methods on the right of this page. We also have medium voltage MV VFDs in stock for immediate shipment.
No One, Anywhere, is better at drives than we are.. . and that includes medium voltage MV VFDs.