Swede, If you have a true 2 speed motor, typically the lower speed will have approx half the current and half the HP rating. (The name plate should tell you). I would make sure you have the right 4 pole connections as that current appears to be a little high if that is off load, I would expect that current fully loaded at 60hz.
The switch usually connects the windings in either a series or parallel mode.
Also if you have the display set for rpm, and you are running at 60hz for a 4 pole motor it will show the speed/freq out i.e. 1800 but with a VFD with no feedback, this display is usually not the true speed but the frequency output, as a 4 pole motor cannot run at 1800 rpm (unless its a synchronous motor) due to natural slip action .
In some cases the overvoltage fault can be if you try to decelerate too fast, the regenerative action of the motor causes the bus voltage to climb above the recommended and the VFD will shut down.
There is usually an internal braking resistor to take care of some braking, for really fast braking, sometimes an external braking option is offered.
Al
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CNC, Mechatronics Integration and Machine Design.
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E. |