powerflex 750 noise issues

I have a 100 HP powerflex drive connected to a Baldor 100 HP motor. This came from Baldor complete with a 28v/v 1024 BEI encoder. I connected every feedback wire as per drawing.

The drive goes through its autotune ok but when i try to run it the motor hunts the zero position. With the currents set to 200% it is extremely loud. So i reduced the current limits to 10% (Motor is uncoupled) So when i turn it on I see the feedback is a moving target at low speeds and there is a distinguished noise at the zero speed.

Now I have started probably 80 of these drives of various hp. So I spent most of the evening reviewing the parameters of some of the larger HP drives in CCW
paying particular interest in the 636,637,638,639,644,645,647,648,649 parameters and there the same or similar.

This is the first Firmware verion 14 drive I have started.

Back to the encoder wiring:

From the drive I have a Belden 3 pair individually shielded wiring the shield is terminated at the red plug and 5 feet away it goes to a terminal block which includes a ground connector for the shield. From the terminal block I have approximately 40 feet of the same wire that is terminated at the cannon connector. The three shields are terminated on the Case Ground of that connector.

So I reviewed three different jobs and noted that everyone was different.
none however connect to the BEI encoder Case ground.

Tomorrow I am going to cut the case ground and remove the grounded shield in the control panel so that the shield floats back to the drive Sh connector.

not sure if I am on the right track but I have to try something.

Its not mentioned if a VFD cable to the motor (shielded power) is used. If not, you have to start there.

The drive motor is connected with vfd wire, complete with copper sheath and ground wires. The wire is connected directely to the drive (no terminals).

Do you have the part number for the motor?

The motor is an Baldor Reliance iddrpm2511004

Have you seen tech note #568004 "Homing the PowerFlex 750 Series AC Drive"?

ronny_resistor said:

I have a 100 HP powerflex drive connected to a Baldor 100 HP motor. This came from Baldor complete with a 28v/v 1024 BEI encoder. I connected every feedback wire as per drawing.

The drive goes through its autotune ok but when i try to run it the motor hunts the zero position. With the currents set to 200% it is extremely loud. So i reduced the current limits to 10% (Motor is uncoupled) So when i turn it on I see the feedback is a moving target at low speeds and there is a distinguished noise at the zero speed.

Now I have started probably 80 of these drives of various hp. So I spent most of the evening reviewing the parameters of some of the larger HP drives in CCW
paying particular interest in the 636,637,638,639,644,645,647,648,649 parameters and there the same or similar.

This is the first Firmware verion 14 drive I have started...

Click to expand...

What Control Mode are you using (V/Hz, Sensorless Vector, Flux Vector)?

Do you know the "motor slip" value?

Have you looked at Parameter 621[Slip RPM at FLA] ?

I would also "consider" the following technote...

578743 - PowerFlex 70/700/750 Series: Slip Compensation differences
Access Level: Everyone

I say "consider" because really you know the application best and whether the information we are suggesting might have something to do with your issue, or not. I, personally, don't like diagnosing large motor applications from afar.

Others are perhaps better at it than me, though.

Regards,
George

George please read below

What Control Mode are you using (V/Hz, Sensorless Vector, Flux Vector)? FV mode (3)

Do you know the "motor slip" value?

Have you looked at Parameter 621[Slip RPM at FLA] ? The Value the drive came up with for parameter 621 was 54.97. The AB tech told me the drive ignores this value if in FV mode

I would also "consider" the following technote...

578743 - PowerFlex 70/700/750 Series: Slip Compensation differences
Access Level: Everyone

I say "consider" because really you know the application best and whether the information we are suggesting might have something to do with your issue, or not. I, personally, don't like diagnosing large motor applications from afar.

Others are perhaps better at it than me, though.

Regards,
George

so today started at 6:00 am and finished at 9:00 PM and we are no further than I was last saturday.

I removed the shield from the encoder Case ground (no change)
I replaced the encoder with a brand new Dynapar (no change)
I replaced the 750-ENC-1 feedback board (no change)
I removed the encoder wire from the machine and laid in front of the machine (no change)
I removed the furrels and inserted the wires into a new plug and directely connected my encoder wire to the encoder card(no change).
I got an Fluke Scope meter and viewed the wave forms (no noise and polarities are right) (no change)
I single ended the encoder leads (no change)
I played with the feedback bandwidth and i was able to lower the intensity of the vibration, ut it is still there.

At one point i forgot to re-connect the encoder plug turned on the motor and thought I had a eurika moment vibration was gone. Then I seen why, re-connected the plug and vibration returned.

I tuned the motor more than 3 times, each time i reset the drive and went through the wizard, Autotune worked ok but in the end it was still the same.

Read somewhere that maybe a HMI tune would improve, it did not.

At 4:00 pm I called my AB sales Rep and went through the list of Parameters with him all he did was give me the AB tech support line (262) 512 8176.

Called the Tech support and went through the same conversation basically outlined above got no where quick. He assured me that the issue is in the feedback stage and I should look at the wiring.

Went back to the machine I even reversed the feedback wire and the vibration was 10X worse. It was then I decided to connect the encoder wire directely to the feedback card plug. And the problem was still there.

Please understand I am not a rookie or a newbie, I have started well over 80 of these drives in the last 5 years (753 and 755's) I have at least 300 Parker 690 / 890 I have started, 4 ABB ACS880's and at least 300 Parker 590 (DC drives)
I have never seen this before.

The issue is that I suspect that there is a parameter that is not set right or the firmware (14.02) may have issues. All my other drives were version 13 or less.

I will play with the slip tomorrow.

Also the application right now is an unloaded motor (just a shaft) getting turned on with out a load. Zero reference, hold position is all i want and then reference the motor to 2100 (maximum) overspeeding by 300 rpm when necessary.

Vfd cable is used 3 XLPE cables with 3 ground, grounded at the drive and motor with Copper foil shielding will check if the foul is grounded it should be as it touches the ground wires.

Maybe this "Application Technique" will help. It has help me a couple of times with troublesome startups.
https://literature.rockwellautomation.com/idc/groups/literature/documents/at/drives-at004_-en-p.pdf

Had an AB tech look at the issue and it turns out that parameter 76 was set to 2.0 Total Inertia. Used to be a 1 in older firmware and was changed in this revision. Autotuned the motor and stability returned.

That's good to hear!

Found this for future reference...

714520 - PowerFlex 750-Series motor oscillations at low frequency in Induction FV with encoder
Access Level: Everyone

Regards,
George

Ok not so much fun. The uncoupled motor ran great with an inertia comp of 1.00 but when I loaded the motor I noticed the speed loop lagging. After changing the loaded motor I was getting an over/unsershoot. So no problem I decided to tighten the speed loop parameters. Had the motor running ok up and down while running looked really tight only running the motor at 100 rpm went for lunch came back. Started the motor at 100 rpm, no problem, 200, 300, 400 and the hammering came back FAACK. So we shut her down and regrouped. Yesterday I was not prepped to do an inertia tune.

So now we are forced to make an inertia tune, having never done one i will be researching this till midnight. The thing is i dont want to run the motor to 3/4 speed, at least not the first try. I want to reduce the speed to something like 500 rpm. We have to goto to 2100 rpm but not sure what the ramification will be. As the drive is PLC controlled through the ethernet cable what ramp values will the drive use ? Currently the ramp is set to 1 second. (PLC ramp is 100 seconds ramp up and 50 second ramp down with a fast stop of 25 seconds as well.

What if the inertia tune picks numbers that will hammer the snot out of my motor. If the first inertia tune (500 rpm) is successful should I try another inertia tune of 1000 rpm would there be a great variant between the two.

I tried lowering the maximum speeds and ended up with a yellow bar across my screen.

Any one? my AB guy who changed the inertia from 2 to 1 cant make it and he told me that it will be fine. Sure easy to say.

I know one guy who destroyed a 300 HP DC motor listening to another companies Tech support. So once bitten twice shy.

The yellow stripe