Derate a VFD ??
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The general priniciple is you take 3Ø, input into a VFD which outputs 3Ø, but variable frequency.
In this case the three phase in, offers maximum capacity for the DC supply that is used to supply the switching devices.
Some models will recommend de-rating their products if used with single phase input, this is due to the lowered capacity of DC supply, which can result in insufficient energy to drive the motor when the motor is running at its rated full load.
If you never drive the motor at its peak, this may not be a problem.
There are makes that manuf. 1Ø input VFD's that have larger DC capacity and therefore do not need de-rating. But it is generally not recommended to use 1Ø supply for over 5HP motors.
Al.
