Dear Sirs, I have an OKUMA LB25 with an OSP5020L controller and an inverter (VAC-DRIVE UNIT TYPE A) OTHER MARKINGS ON THE INVERTER ARE D22-A, motor 15/11KW, LB25.
The problem with this inverter is that it is tripping when speed is reduced or electronic break is activated. Therefore it seems that some sort of back EMF or feedback is not working as it should. This defect started when we had a Voltage dip and the unit tripped. However if I reduce the speed gradually (manually) and then I stop the motor, this does not trip. When the speed is high or at a higher percentage, it will trip anyway. The only way to reset is either to switch off and on again or press the reset button on the inverter. When the fault occurs, the two RED LEDs (alarm A) flash.
Can you please guide us or a quick check, preferably to avoid sending parts and be without the lathe. We are an electronics R&D company and have the technical people and equipment and can easily follow your guide lines.