text: <s>[INST] Powerflex 755 Drive faults Summary: Precharge, Alarm 14, + some questions Hi, I'm having a few problems with two of these drives and I would like to just confirm some things with someone who isn't guessing. Im fairly new to the drive and job so im still trying to figure things out Why would the DC bus voltage be up, but not show the DC voltage up status? Why would the drive have power on the 3phase incoming, but the DC voltage remain down until you send a reset signal to the drive? I have seen Alarm 14 which is ground fault, I think this may be my actual overall problem, but I want to ensure I have everything covered before telling the customer his ground is rubbish, it’s a large reputable site, however saying that, it is based in china Why would the drive sit in pre charge and require a reboot to run again? I have read through some manuals, and I think it might be down to the PWM exceeding 125% of my line to line voltage dropping out disabling the precharge for the drive, however sleep has been a problem lately, and im at wits end, so I may just be seeing the words I want to see to blame the ground When should you take the enable signal off the drive? If the drive was being given a motion command while the enable was dropped could I we be causing problems? And in turn, a motion command before the enable is active Should we be dropping the 3 phase power to the drive roughly twice every 10 minutes? If we drop the 3 phase voltage is there a minimum time before we should re apply it? Any help would be greatly appreciated Thanks [/INST] Page 13 of the programming manual (I have revision I, July 2013 handy) and page 13 of the reference manual (September 2013) says you should power-cycle the drive no more than one cycle a minute. That said, if you are using an input contactor to drop line-in AC power to the drive, you should consider using a safe-torque-off option card. This uses 24VDC signals to disable the output stage of the drive so you do not have to constantly cycle line-in power. You need to attend to the ground warning alarm 14 before anything else. Having significant current being measured to ground means there are real wiring problems. The ground conductor coming back from the motor should be landed on the drive PE terminals and no where else. Landing it on the back panel or on a grounding lug separate from the drive could be one cause of this. What size drive is this? What line-in voltage? \\n </s>