Initialize a VFD thats been unused??

Metalurgent · May 7, 2020

I'm retrofitting a Tree Journeyman that's been out of action for a few years. I reset the Yaskawa CIMR vfd to factory presets and got the spindle motor running at the default settings.
The motor made some noises that I assumed were bearing problems so I pulled the motor and have new bearings on the way.
I came across a warning that a drive needs to be reconditioned if it has sat unused for a while ( quotes below..). I'm new to this stuff so that recommendation seems odd to me. It this a generally accepted practice??

"VFD can sit unused and without power for a short time without service. If a VFD has been stored for longer durations, the dc bus capacitors must be reconditioned. The electrolyte inside the bus capacitors changes state when unused for long periods. Reconditioning requires running the drive with no motor leads connected for at least 8 hours before trying to run the drive under load. Repowering the drive under no load brings the electrolytic charge back to a proper charged state."

CalG · May 7, 2020

If the vfd powered up on mains voltage, don't fret. The magic smoke is still in there.

I might have put the unit on a variac and stepped up the voltage from 30V to 100V over a couple of hours, just to gently rouse the electrons in the capacitors.

But it sounds like that has been taken care of without troubles... Unless you "motor sounds" are VFD driven....... hmmm.

Metalurgent · May 7, 2020

It's 3-phase input, I don't have anything that could ramp up input voltages, with or without the motor connected. In any case, is the "8 hours with no load.." a regular precaution?

ptsmith · May 7, 2020

Metalurgent said:
I'm retrofitting a Tree Journeyman that's been out of action for a few years. I reset the Yaskawa CIMR vfd to factory presets and got the spindle motor running at the default settings.

Not an expert, but what you might be hearing is the VFD carrier frequency, which can be loud at default settings.

And there is a setup process. You have to configure the VFD to your motor specs. Google your model (V1000, A1000, etc.) and "quick start guide" to get the basic setup info.

Metalurgent · May 7, 2020

Seems there is a precedent for taking it slow with these devices..
News to me.

Capacitor Reformation and Maintenance Recommendations Using an AC or DC Input for Drives which have been Stored for Extended Periods
https://solutioncenter.yaskawa.com/...F9B893E9110674DEEB?externalId=10214&sliceId=1

Metalurgent · May 7, 2020

ptsmith said:
Not an expert, but what you might be hearing is the VFD carrier frequency, which can be loud at default settings.

And there is a setup process. You have to configure the VFD to your motor specs. Google your model (V1000, A1000, etc.) and "quick start guide" to get the basic setup info.

When I pulled the bearings, they really weren't as bad as the noise was suggesting and there was an overlay of a harmonic "whine" in there too. I have the manual for the drive and I'll see what it says about matching to the motor. The quick-setup got me into the menu to reset to the defaults, but, as you suggested, there are definitely other adjustments to be made. There are some wiring issues that have to be worked out to allow remote operation from the new control. In the meantime, I'm working off the built-in programming panel.

Froneck · May 8, 2020

The fact that you power-up the VFD is too late to worry about conditioning. Capacitors that have been sitting for a long time should have voltage supplied much lower that normal and slowly brought up to operating voltage. You don't mention how long you operated the VFD at full voltage but I think it's too late to worry about it now. You can probably wire a few older Incandescent light bulbs in series with your VFD powering only 2 of the 3 inputs. Then after time remove one bulb at a time to increase the voltage in steps. Probably easier to screw in one of those old screw in fuses in the bulb socket to increase voltage. Don't connect the motor until after your at line voltage of the VFD.

jim rozen · May 8, 2020

Metalurgent said:
I'm retrofitting a Tree Journeyman that's been out of action for a few years. I reset the Yaskawa CIMR vfd to factory presets and got the spindle motor running at the default settings.
The motor made some noises that I assumed were bearing problems "

The VFD may have been tuned specifically for that motor in that machine. Resetting to factory parameters would undo that. A motor that is being run by
a drive that is not tuned properly can make some 'intersting' noises, often which are speed-dependent, ie they come and go as the speed ramps up. Things
like chatter or rattle might be just a mis-tuned drive. See if the drive supports and auto-tune function.

Metalurgent · May 8, 2020

Froneck said:
The fact that you power-up the VFD is too late to worry about conditioning. Capacitors that have been sitting for a long time should have voltage supplied much lower that normal and slowly brought up to operating voltage. You don't mention how long you operated the VFD at full voltage but I think it's too late to worry about it now. You can probably wire a few older Incandescent light bulbs in series with your VFD powering only 2 of the 3 inputs. Then after time remove one bulb at a time to increase the voltage in steps. Probably easier to screw in one of those old screw in fuses in the bulb socket to increase voltage. Don't connect the motor until after your at line voltage of the VFD.

So do these precautions apply in other components with filter/power capacitors? The servo drives are a 3-axis ganged set that take 110vac input from a big double transformer in the base of the control cabinet. Baldor UM4. A rectifier/filter section on this with some large caps and diodes feeds each servo amp. Should the voltages be ramped up here too before I hit the dc section with the full 110v? I do have a big variac that I could use. Having to replace the drives would be a huge expensive nuisance and I'm already annoyed at myself for potentially screwing up the vfd

CalG · May 8, 2020

Here is a question that just passed through my otherwise empty head.

How to evaluate the input, AC/ DC conversion setion of a VFD ?

With only a multimeter..... (A scope would give wave form, but there must be an acceptable AC component that can be measured.)

Just set the MM on AC and put the probes on the DC buss terminals and read the value? Is 2% of line voltage no load, 6% AC ripple at full load reasonable?

What would be too much?

Some things might be better left unknown....;-)

mksj · May 8, 2020

Electrolytic capacitors degrade over time, and to some degree can be reformed by slowly stepping up the voltage with no load. These may be exacerbated when first applying power to the capacitors because of the high inrush amperage. There are also issues of heat generation internally in the capacitor. Most VFD manufactures recommend applying power to a VFD at least annually, some suggest stepping up the power others just apply power for a period of time with no load. Yaskawa does have a white paper on this subject.

This applies in general to electrolytic capacitors in older equipment/power supplies that have not been used for extended time. Limiting the turn on inrush and reduced voltage is probably recommended, my only concern would be the risk to other components at low voltages. I am assuming there is some form of regulation any maybe dropout at low voltage. Alternative as stated would be to minimize the current draw once powered up.

I would be hesitant to reset the VFD to factory defaults without first recording the specific machine parameters, which hopefully you did. The few specs I have seen for a few of Tree Journeyman motors are not what one would consider VFD factory defaults, and I would expect many parameters would be different.

Metalurgent · May 9, 2020

Thank you. Good information.
I'm going to tiptoe through the rest of the install for both the vfd and drive. I know newer replacements are available but the cost for industrial grade stuff can make your eyes widen.

rons · May 9, 2020

I'm using a small variac connected to a 120/240 transformer. Then a diode bridge with filter capacitor on the 240 side. Gives me a variable DC supply.
But not very responsive if I were to change the voltage up and then down. But since I will only be going up then no problem. The method is to connect
directly to the filter capacitors in the VFD. Just be sure all the temporary connections into the VFD are 100% secure.

Metalurgent · May 9, 2020

rons..
Just to clarify..are you suggesting that individual capacitors can be connected to a variable dc supply (with clips? ..) and then ramped up to just short of their max voltage capacity to condition them? Then what? Turn down the dc slowly? Just disconnect the pigtails and let the caps bleed down?
This is like open heart surgery for me and I'm just a bit uncertain that I could/should be screwing with big caps in this way. Again, if I'm off track let me know.

rons · May 9, 2020

Metalurgent said:
rons..
Just to clarify..are you suggesting that individual capacitors can be connected to a variable dc supply (with clips? ..) and then ramped up to just short of their max voltage capacity to condition them? Then what? Turn down the dc slowly? Just disconnect the pigtails and let the caps bleed down?
This is like open heart surgery for me and I'm just a bit uncertain that I could/should be screwing with big caps in this way. Again, if I'm off track let me know.

I wil turn the power off and a bleeder resistor with led lamp wiil discharge the VFD capacitors. It takes about 6.5 minutes for the voltage to decrease to about 6vdc.
My VFD's have the +DC bus tied to a connector so it makes it easy. Although the capacitors are not that hard to get to underneath a plastic panel.

mksj · May 9, 2020

At this point you have already powered up the VFD, so I do not see that you need to reform the capacitors, I would just leave the VFD on for 1-2 hours.

Yaskawa Drive Storage Maintenance Recommendations

https://solutioncenter.yaskawa.com/selfservice/viewContent.do?externalId=10214&sliceId=1

JST · May 9, 2020

mksj is correct, assuming you had the VFD on for more than a very short time.

There is little risk in simply leaving it powered up at this point, since if it has already accepted 5 or 10 minutes "on", it is unlikely to suddenly fail now.

Metalurgent · May 9, 2020

Thanks for all the information. My go-to procedure until now was to "plug something and to see if it works". Basically treat everything like a light fixture..
I'm working on setting up the servo drives now. When I've got them connected and running, I'll get back to tuning the VFD. The big power transformers for servo AC in the cabinet run directly off the same input power as the VFD and I'm guessing it would be prudent to have them connected before tweaking the parameters.

motion guru · May 10, 2020

If you need to know what the factory settings are for your Yaskawa spindle motor, I have copies for most tree spindles, and can send them to you.

Metalurgent · May 11, 2020

motion guru said:
If you need to know what the factory settings are for your Yaskawa spindle motor, I have copies for most tree spindles, and can send them to you.

Great, I will send you a PM.

Initialize a VFD thats been unused??

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