According to Jon Elson :
DoN. Nichols wrote:
According to Alex :

I need help connecting my VFD to a motor.

I connected my VFD (KBAC-27D) to single phase 240V
VFD shows code "Undervoltage"
I measured voltage between AC lines - 237V, between one AC line and ground - 117V
another AC line and ground 117V
It's a little less than suppose to be but should be OK I guess.
Can anyone shed some light on this problem?


It is complaining about the third phase terminal, which is not
connected to anything. Try jumpering it to the nearest terminal which
does have power, and that should eliminate the complaints.

Some VFDs care about this, others do not.
Looking at the data sheet he referenced, there are only two
line terminals.

So there are -- but this was in a followup by someone other than
the original poster, and I had not seen it when I answered.

This is a single-phase only input VFD, which
can be set for 120 or 240 V operation.

So it is -- which suggests that either some of the jumpers are
not quite set right, or that there are glitches in the power line
connection (loose connection) feeding the VFD, causing the undervoltage
to appear momentarily.

Enjoy,
DoN.

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