DIYbanter - View Single Post - is it possible to use AC motor with inverter in 4Q mode?

In article . com,
says...
just want to be su
does its mean that AC motor with encoder and vector drive can operate
torque on the opposite side of rotation?

That's right. I assumed by "4Q mode" you meant four quadrant operation.

You do need to be sure the energy regenerated by the reverse torque has
someplace to go. Not a big concern with, for example, a camshaft where
the torque reversal is of short duration and there's enough capacitance
in the DC supply bus to absorb the energy. You need to pay much closer
attention with a load like an elevator, the classic overhauling load.

Ned Simmons