Vfd

[JesperMP]

Oh, I just remember one detail that I found irritating with AB PF70 VFD's. I control the drive via a network card, and there is no separate power supply to the network card or the control electronics. Thus cutting the power on the input side promptly triggers a bus fault as well. So it would seem that AB in principle expect a contactor to sit on the output side.

On Siemens MM4 VFD's the network card has a separate power supply, so in stead of a bus fault, you can get a meaningful error message "No input voltage". So it seems that Siemens in principle expect a contactor to sit on the input side.

edit:
Found a picture for Siemens MM4 with the contactor on the input side.

 

[MavEric]

Breaking the input power to a drive on a typical network, DeviceNet, ControlNet and Ethernet IP does cause a network fault, however after powering the drives back up, they reconnect. We are doing this on every system, with any of the 3 networks listed.

 

[khanz]

Hi all,
thanks a lot for your comments. I really don't know much of the information about contactors. thanks once again for your replies.

 

[OkiePC]

If it is for safety, be sure to use the SAFE-OFF optional module in the powerflex drive. Don't rely on the standard digital input alone. The safe off option is a tiny relay that kills gate power to the IGBT power modules in the drive when it loses power.


Paul