Powerflex 525 drive controlled via logix5573

If you've done all the above, can you killed power and swapped two of the incoming/line to the drive and see what happens?

Was possibly going to try that next buts its a delta connection so not to sure if that will work.

Changing the infeed supply to the PF525 will have no affect on the output phasing, as with all VSD's the incoming supply is changed to DC then converted back to AC which is controlled by the direction bit in the VSD.

Alan.

Hi Alan, what paramater would this be

Bit 4 in the command word is for forward and bit 5 is for reverse, when sending the commands from the PLC.

As you are controlling the PF525 with a PLC, there is no "bit" in the drive to change direction in a PF525 unlike a PF750 series drive if it is going in reverse then you can change a bit to change the output polarity, but in the PF525 there
are only 2 ways to change direction if it is going the wrong way is to change the commanded direction or change the output wiring.

Alan.

Hi Alan , so only to change it is from plc if its controlled via plc will have a look at it with rslogix tomorrow. Thanks

Hello Danaus,
Were you able to solve your problem? Please let us know

You should be able to change the direction by swapping the phase on the motor side or through the logic on the PowerFlex 525 AOP. Either one should work. The fact that you weren't able to swap it with the phases makes me think that there's a different issue happening here... Was anything changed on the mechanical side? Are the couplings to the machine the same? Anything that may prevent it from running in the opposite direction?

If you are expecting the DISPLAY on the VFD to change when you swap wires in the motor, that is your mistake. The display is simply telling you the phase order of the VFD output; A-B-C is FWD, C-B-A is REV. What that does to the motor depends on what the connections are in the motor, the VFD has no idea what direction the motor is actually turning.



Inside of the VFD programming, there is a parameter, A544, that allows you to disable the VFD's ability to allow the motor to run in reverse. The factory default is "0", meaning Reversing is ENABLED. If it is set to "1", reversing is disabled and no matter what you tell it, the output will always be A-B-C. But again, that does NOT mean that the motor itself cannot be reversed by swapping leads, it just has to do with the output transistor firing sequence.

danaus said:

Yes I am looking at the right motor, How do I get the fwd to display Rev

Swapped blue and white around at the motor terminal block

Click to expand...

As others are alluding to, something fundamental is missing or a miss here. The 3 phase pump motor should definitely change direction if you are successfully swapping 2 of the 3 phase motor leads. The drive will not have any immediate or automatic influence over this. If FWD is selected on the drive then you should be able to change direction via the wiring until satisfied that the actual forward direction is achieved.

It is good practice to commission a drive application, even if not intended for forward/reverse operation, so that the actual forward direction is represented by the forward (FWD) command on the drive. Changing a drive command to reverse (REV) so as to achieve actual forward direction is not good practice. I could call it lazy to boot. But that is debatable depending on the size and complexity of the design. Phase rotation detection is an important tool here, though.

The reverse disable parameter only disables the drive from asserting a change from FWD to REV direction. It does not govern the output to the point of monitoring phase rotation and auto correcting to prevent a change to reverse after the motor leads have been swapped.

If the pump is not reversing after swapping 2 of the motor leads, then what makes you think that changing the direction via the Logic Command will be any different?

Regards,
George

Stay Safe!

Geospark said:

As others are alluding to, something fundamental is missing or a miss here. The 3 phase pump motor should definitely change direction if you are successfully swapping 2 of the 3 phase motor leads. The drive will not have any immediate or automatic influence over this. If FWD is selected on the drive then you should be able to change direction via the wiring until satisfied that the actual forward direction is achieved.

It is good practice to commission a drive application, even if not intended for forward/reverse operation, so that the actual forward direction is represented by the forward (FWD) command on the drive. Changing a drive command to reverse (REV) so as to achieve actual forward direction is not good practice. I could call it lazy to boot. But that is debatable depending on the size and complexity of the design. Phase rotation detection is an important tool here, though.

The reverse disable parameter only disables the drive from asserting a change from FWD to REV direction. It does not govern the output to the point of monitoring phase rotation and auto correcting to prevent a change to reverse after the motor leads have been swapped.

If the pump is not reversing after swapping 2 of the motor leads, then what makes you think that changing the direction via the Logic Command will be any different?

Regards,
George

Stay Safe!

Click to expand...

This is what I was trying to say.

I'm not an expert in mechanical systems, but I've seen ways to have the system limit the rotation to a single direction through mechanical means. Belts? Sprokets? Gears?

Vlad,

What you are referring to, I believe, are mechanical options such as check valves and non-reversing ratchets or clutches, the latter more used on large turbine or deepwell vertical pumps. These are used to mechanically prevent the pump and motor from reversing due to backlash when stopped and the fluid head "falls". Or if the positive head pressure builds, say against a closed valve, creating back pressure. Or if the motor single phases, for instance. Some pumps may also have special seals or trust bearings which reversing could damage. There is also the risk of certain threaded impellers unscrewing from the shaft when reversed. But the above measures are just designed to mechanically prevent reversing. They cannot, of course, prevent reverse direction wiring of the motor leads, say at commissioning. That is why for many pump applications it is manufacturer recommended and necessary to verify the motor direction before it is coupled to the pump assembly.

So if a ratchet or clutch was fitted to this pump application then the pump/motor could only physically rotate in the correct direction. Such mechanical measures would not prevent you changing direction to get the pump rotating in that correct direction, which I think you might be implying?

If just using say check valves, or of course nothing at all, it would be possible to swap motor leads and observe the pump rotating in the reverse direction.

Depending on the type of pump we're talking about here, and the available "optics" while attempting to change direction in order to get it to to go in the correct direction; I would be curious to know how it is being determined that it is running in "reverse" since the drive was changed, and that it is not changing direction when 2 motor leads are swapped? For instance, is there an arrow on the pump casing and the impeller is visibly turning in the wrong direction. Or is the actual pump direction not visible and there is just no flow observed, or some other erroneous observation? Is there noise, vibration, heat observed? High current measured, pumps in tandem, and so on. Is the pump motor single phasing, perhaps? Why was the drive changed? Was it considered faulty when perhaps the root cause is in the field? Or was it upsized and if so, was the pump, meaning recommissioning required? Lots to consider and guess at here.

It's not to say our friend is inexperienced. It's just we don't know their level of experience and we many of us have met those cases where folks are a little misguided or perhaps "Green". For instance, if you know how swapping 2 phases on a 3 phase motor should definitely change its direction, regardless of a drive, then your experienced focus should remain on why the motor is not reversing for you, if that is actually the case, and not be quickly diverted to, or falling back to, trying to mitigate the field issue with a reverse direction command in the drive.

If experienced, this is lazy. If inexperienced, bravo for trying to "think on your toes". But it is still misguided.

Regards,
George