Overview of variable frequency drive technology (part 3)
Continued from: Overview of variable frequency drive technology (part 2) , I will still concentrate on VFD.
As we know before, there are some advantages of variable frequency drives (VFDs, variable speed drives). But of course variable frequency drives (VFDs) are not perfect. There are some drawbacks too.
For example, the very fast voltage rise times associated with insulated gate bipolar transistor (IGBT) technology contributes to precise motor speed control. But it can also lead to voltage spikes that damage cables of poor quality, or ones that are improperly insulated.
Other possible concerns with use of variable frequency drives (VFDs, variable speed drives, VSDs) are the potential for acoustical motor noise and motor heating, when currents, induced by pulse width modulated (PWM) switching, flow in improperly grounded motor shafts. The result can be damaged bearings.
What's more, the purchase cost for a new variable frequency drive (VFD) can be steep, though this must be balanced with the fact that the payback period can be a matter of just a few months to under three years.
