Andrew Evenson
Member
Hello,
I am hoping someone can give me some insight on the current wiring of some AC drives we are currently using.
A bit of a background. We are currently starting to experience failures on some of the drives in a 20-25 year old panel. The Current mix of drives are Mitsubishi Z260's , AB Bulletin 1333, and newer Mitsubishi A560 AC drives.
We have limited spares and its getting harder to source the same drives.
Within the next 2-3 years were are planning to do a complete control systems upgrade, so I'm looking to replace a few of the existing drives with a more modern/common drives we are using elsewhere in the plant to keep us running until the upgrade as we don't know which vendor platform we will be going with.
I was planning to use AB PowerFlex 70's.
Now, onto my burning question.
The existing drive's digital inputs (both Mitsubishi and AB) are "sinking". Our PLC provides a relay contact for FWD/REV jog commands to each drive. What the original designer did was tie all the digital input commons together. Now, the AB drives's have 5 VDC logic and the Mitsubishi's have 24 Vdc logic. Is this a common practice? I personal don't see this too often. I have attached a very simplified drawing to show what I mean.
My worry is the interfacing wiring for the PowerFlex 70. It says the digital inputs can be either sinking or sourcing, but I'm leary of connecting the commons together of 2 of the new and old drives.
I hope my question makes sense. Maybe I should ask simply, can you time the common of different voltage DC supplies together when using sinking digital inputs??
Hope my question makes sense. If not, please let me know and I'll try to clarify...
Thank you,
Andrew
I am hoping someone can give me some insight on the current wiring of some AC drives we are currently using.
A bit of a background. We are currently starting to experience failures on some of the drives in a 20-25 year old panel. The Current mix of drives are Mitsubishi Z260's , AB Bulletin 1333, and newer Mitsubishi A560 AC drives.
We have limited spares and its getting harder to source the same drives.
Within the next 2-3 years were are planning to do a complete control systems upgrade, so I'm looking to replace a few of the existing drives with a more modern/common drives we are using elsewhere in the plant to keep us running until the upgrade as we don't know which vendor platform we will be going with.
I was planning to use AB PowerFlex 70's.
Now, onto my burning question.
The existing drive's digital inputs (both Mitsubishi and AB) are "sinking". Our PLC provides a relay contact for FWD/REV jog commands to each drive. What the original designer did was tie all the digital input commons together. Now, the AB drives's have 5 VDC logic and the Mitsubishi's have 24 Vdc logic. Is this a common practice? I personal don't see this too often. I have attached a very simplified drawing to show what I mean.
My worry is the interfacing wiring for the PowerFlex 70. It says the digital inputs can be either sinking or sourcing, but I'm leary of connecting the commons together of 2 of the new and old drives.
I hope my question makes sense. Maybe I should ask simply, can you time the common of different voltage DC supplies together when using sinking digital inputs??
Hope my question makes sense. If not, please let me know and I'll try to clarify...
Thank you,
Andrew