Originally Posted by
TeaManMachine
Not to change your mind or anything, but I would be cautious to push a 1400 RPM motor up to 3360 RPM. The motor was designed for 1400 RPM with an engineering fudge factor. The bearings are not rated to double the speed, though you probably won't be there all the time. If these are Chinese motors, I'd really be cautious. Their standards are not where they should be. They fail within their duty cycle, can't imagine what happens when you double it.
TeaManMachine
I have installed a few VFD's over the years and consistently used 120hz on a 4 pole motor, part of my reasoning is that I would imagine the motor manufacturer would use the same construction standards, bearings, balance etc, for a 4 pole as he would the 2 pole version?
Also the 4 pole has the advantage on lower rpm due to the fact there is 2 Electrical Revolutions per mechanical of the motor, compared to a 2 pole motor that only has one E.R.
Also it pays to get the sensorless vector version of VFD rather than the cheaper variable speed version.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.