# Difference between VFD and Curtis Controller



## brian_ (Feb 7, 2017)

"VFD" means Variable Frequency Drive, and so all AC motor controllers could be called VFDs... but they're not. Usually, the term VFD is used to refer to controllers which take in AC power at a fixed frequency (presumably 50 Hz in Thailand), rectify it to DC, then invert that to provide AC power of the right frequency for the motor speed. An AC controller in an EV (such as one from Curtis) starts with DC power from the battery so it doesn't have the rectifier section, just the inverter.


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## attz (Oct 23, 2019)

Thank you very much Brian


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## remy_martian (Feb 4, 2019)

EV-Thai (publicly traded company on the Bangkok stock exchange) in Samut Prakan has been making EV's for a couple of decades... they may have salvage pieces you could use.


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