Single Phase to Three Phase VFD

[CommAgent]

Hello All hope someone can help me.

I am working on a project which requires single phase to three phase conversion for some motors. This is being accomplished by using VFDs, ABB ACH550-UH HVAC Drives. There are a total of 4 drives being used to power 4 seperate motors. 3 of the drive motor combinations work well, but 1 drive motor combination displays a fault, and does not operate correctly.

The specifics are below:

The motor is 5 HP motor 240 Volt, the drive has been derated because of the phase conversion and is a 10HP drive.

When the drive first powers the motor, the motor acts like it is single phasing and starts with a jerking action, and continues to vibrate like crazy. The motor has been removed and tested by a motorshop with 3 phase power,and came back with no errors.

One of the legs of the power from the drive to the motor was drawing a lot more current. 2 legs were drawing around 11.8 amps, and the other leg was drawing 15.86 amps (at 45hz before drive faults). All electrical connections were double checked and found to be tight.

The drive will only run up to around 45hz (with much shacking and vibration of the motor) before it faults. The error code is Supply Phase - Ripple voltage in the DC link is too high.

My thoughts are that for some reason the capacitor in the drive is either not big enough, or is not functioning properly, which is causing to big a ripple voltage.

I am recommending a replacement of the drive, and possibly a larger drive, but because this project is so far North and the expense to get the drive flown in is fairly high, I want to make sure that I haven't overlooked anything.

Any ideas or recommendations?

Thanks in advance,

Jamie

 

[itsmoked]

I think you do have a serious drive problem.

1) I would try to reset the drive to defaults. Then carefully copy every setting from a working system.

2) Hook the single phase you have to different terminals which will feed the drive thru different rectifiers as maybe a rectifier is toasted.

Since you have this remoteness problem
3) I would hook one of the other drives to this motor and confirm a bad drive.

4) Get a replacement.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[jraef]

The absolute rule on drive derating for 1 phase input is to use the square root of 3 (motor FLA x 1.732) because that covers the additional current going through the diode bridge. Then most of use 2.0x the FLA as a minimum because that will provide extra capacitance for smoothing out the higher DC bus ripple. So it should have worked, as evidenced by the fact that 4 out of 5 did work. I would then agree with itsmoked that you probably have a bad drive, i.e. a bad transistor, a blown capacitor or maybe a bad diode on the bridge (or any combination thereof).

Maybe someone more familiar with ABB ACH550 drive topology such as DickDV will chime in, because I think ABB uses a DC bus choke (inductor) and therefore may not use as much capacitance. That, combined with the fact that the ACH is a VT rated drive and therefore "lighter duty" rated than the ACS may be leading to their possibly not being able to handle 1 phase input with that model. But I seriously doubt it to be honest, that's a very standard application. It's more likely an out-of-the-box failure of some sort.

 

[DickDV]

I agree with the previous posts that you should swap a good drive onto the motor in question to verify that the motor and leads are OK.

Sounds like a serious drive problem to me. Plan on replacing it. Standard warranty is one year from startup unless registered by a certified startup tech. Then it's two years.

 

[ozmosis]

My understanding of the ACH550 drives running on a single phase supply is that the factory/authorised ABB person needs to make certain software changes within the drive to ensure the drive does not trip as a result of the high DC link ripple you will get with a 1ph input. It may be possible that the other 3 drives that are running ok are not drawing as much current as the one that is tripping and so it may be worthwhile going back to ABB and informing them that you are running all drives on a 1ph input. They may advise how they should be set up. The drive should have a protection anyway that indicates an "input phase loss" and so this should have been disabled too. The phase loss detection will be looking at the ripple on the DC link to determine whether you have all 3 phases intact.

 

[itsmoked]

So Ozmosis rears his ugly head again.. LOL

Must've made it down under without the boat sinkin?

Welcome back.

I would think that the drive wouldn't continue to rattle the motor if it was tripping out on a normal ripple complaint. I think something is toasted.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[DickDV]

The 550 series drives do not have a parameter to turn off for single-phasing the input.

The drive is bad, pretty sure about that.

 

[ozmosis]

Thanks Keith, you say the nicest things...

I'll bow to DickDV's better knowledge but I thought there was something in the 550 to compensate (up the limit) for dc ripple.
Must be all this blood running to my head working in the S.Hemisphere again.

 

[itsmoked]

Haha Good point!

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[jraef]

Off topic:

Hey ozmosis! Welcome back. I had a chat with your friend Alex today at a training function we are both attending in Atlanta and told him I saw your post indicating you had arrived safely down under. He wants your new email address.

 

[jraef]

Back on topic:

The more I think about this, the more it points to a failure. Even if there were too much ripple, that would not make only one of the output legs different from the others. More likely to be a failing transistor is causing too much ripple but has not failed catastrophically (yet) so the only thing the drive trips on is the ripple effect.


Hmmm... Ripple Effect sounds like the morning after a night of drinking cheap wine!

 

[Skogsgurra]

Landed upside down? Did you, oz? Welcome back to existence!

Gunnar Englund

http://www.gke.org

--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[boaterbill]

I would check the buss fuses.

I had an ABB ACH 500 do a similar thing about a year ago. Ramp up to about 40-45hz and trip.