Powerflex Drive help

Hi Everyone,

I use this forum for some problems that I usually have with PLC, but I currently have an issue with a Powerflex 753 drive. Can anyone re-direct me to a good Drives Forum?

Thanks
Victor

there are many posts on this site - too many to paist here
enter the drive type and brand in the search bar
Powerflex 753
they will come up

Ok, so maybe let me ask the question .... see where it goes

We have a customer that has a Pumpstation with 4 identically sized pumps (250kW). He had 4 identical PowerFlex 400 drives installed. Unfortunately, one of his drives got damaged and he has now replaced the damaged one with a PowerFlex 753 - this is where the fun begins !!

He has the following scenario:
1 - When he runs the PF753 drive on it's own, no problem
2 - When he runs the PF753 together with ONE PF400, the PF753 starts to overheat, and eventually trips (after a few hours)
3 - When he runs the PF753 together with TWO or THREE of the PF400, then no problems again !!

What could be the possible reason for this behavior?

Has anyone seen anything similar happen?

Thanks
Vic

2 - When he runs the PF753 together with ONE PF400, the PF753 starts to overheat, and eventually trips (after a few hours)

Click to expand...

Is there a drive fault? what F#, or does the motor/pump overheat?

It looks like a supply power issue and/or load side EMF interference...The VFDs are probably sharing the same power supply and there isn't enough filtering (line side Line Reactors) or the VFDs load side field wiring is sharing the same conduit run using conductors which's insulation is deteriorated.
I would first ensure there is a properly sized line reactor for every VFD line feed; load side chokes are recently available and could be installed before deciding the field wiring replacement.

Whether the drive is overheating or the motor, it still looks like, when only two motors are running, they are not sharing the load evenly. Check the running amps of the two drives before you get the fault and see if they are balanced.

If the load is not balanced, then most likely the control system is not regulating the two motor speeds evenly. I don't know just how the controls are configured to loadshare but my guess is that's where your problem lies.

When more than two motors are running, the loadsharing is still probably not balanced but, with more motors working, none are loaded heavy enough to cause a fault.

Let us know what you find, please.

One thing to keep in mind is the Speed Scaling of the PowerFlex 400 and 700 Series is very different. Has this been addressed?

Stu.....

I understand you have 3 pf400's and 1 pf753.
Please clarify that the same fault occurs with any One of the PF400's running with the PF753.
also can you provide a JPG picture of the panel layout.
it sounds like you have an air flow problem - maybe the internal cooling of the panel is circulating incorrectly - even may be opposing or restricting the air flow of the new drive