VFD rather than VSD
VFD rather than VSD
(OP)
Hi,
I have seen many posts using the term VSD rather than VFD.A variable frequency drive varies the frequency which is a vector quantity rather than speed which has got magnitude only and no direction.
Bob
I have seen many posts using the term VSD rather than VFD.A variable frequency drive varies the frequency which is a vector quantity rather than speed which has got magnitude only and no direction.
Bob





RE: VFD rather than VSD
VSD (as well as ASD) is actually a more generic term. It can mean a DC drive, an eddy current drive, a fluid drive or a mechanical variable pulley system such as a VariDrive or Variator. People use VSD quite often, but they really should probably be more specific since it can and does mean many things.
Inverter is another problematic term used a lot for VFDs. Technically, all VFDs have an inverter in them because that is the heart of the technology, but there is also a converter at the front end, and there are also plain inverters that are NOT VFDs. So again, it is technically too vague.
Side note:
To make matters worse, especially when searching the internet, VFD also means Vacuum Fluorescent Display, Voluteer Fire Department, Variable Field Data and a host of other non-motor related terms. Makes life interesting.
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PowerfulStuff (Electrical)
Hi,
aolalde (Electrical)
Hello Maypot:
Read the Eng-Tips Site Policies at FAQ731-376
RE: VFD rather than VSD
Just one more from a long time ago - many older units were called VVVF drivess - Variable Voltage Variable Frequency. Probably more correct but I haven't seen it used for ages.
Regards,
Martin
RE: VFD rather than VSD
The regional uses must influence the terminology. It depends on how generic or specific the drive description is intended. Some other examples are; AFC for Adjustable Frequency Controller, VVI for Variable Voltage Input driver, CSI for Current Source Input Inverter, PWM for Pulse Width Modulated Inverter, etc.
BTW (not a driver, but by the way) I do not consider frequency a “Vector” since vector quantities must have magnitude, direction and obey the parallelogram law of addition; like force, magnetic field, voltage differential, electric current, including velocity, etc.