KBAC 27D - saga goes on !

R

rashid11

Joined
Dec 8, 2005
Messages
707
OK,

they looked at the drive I sent back
and found "nothing wrong". %@+()#$%*$)(%* !!!

I am hoping something was changed/fixed/replaced or
whatever. Or may be something got shaken loose and
into the proper state during shipping. Or may be my
fluorecent lighting is playing havoc (no way).

But, stopping short of such miracle, I might be looking
for a buyer for a new KBAC27D :grumpy: , at a loss
to myself.

I can not beleive 2 different, brand new motors I have: difft makers, HP,
RPMs etc, could be bad. Neither could I possible screw up with 3 wires (2
hot legs of 220V + ground) going in and 3 going out.

Definitely, the vibration that this controller induces into both
motors, through hole range of speeds, is not acceptable .



I know 220V circuit is good, as I use it daily for: heat treat oven,
Bandsaw, MIG and TIG. May be 15f of 3x12 gage wire from 200A
main breaker panel, through 2x20A breakers. No way I am having any significant voltage drop over that.
 
Did you try swapping a couple legs of the output? Do you have the ground wire tied to the motor chassis ground screw and the appropriate terminal on the VFD?

Very wierd.

If you do decide to off it, it should sell quickly.
 
J. MacDonald said:
Did you try swapping a couple legs of the output? Do you have the ground wire tied to the motor chassis ground screw and the appropriate terminal on the VFD?
Click to expand...


Good suggestions! Swapping the legs around was the first thing that came to my mind as well.
 
I've got to think that a vibration is a mechainical issue...not an electronic issue. I had 2 differnt home built 3phase convertors with idler motors. One was 3hp and the other was 10 hp. Both were 3 phase motors but only running on 1 leg...and they both ran smooth as silk.

Looking through some of your previous posts, I've got to wonder if the vibration isn't coming from your duct tape covered contact wheel or casters.

Did you use the same wheel or pulley on both motors that caused you problems? Could it be that, THAT pulley or wheel is out of balance? I've had fits with die-cast pulleys...both out of balance and non-concentric.

I'l be glad to help you out if I can.
 
:rolleyes:

No, I tested both motors by themselves, w/o anything attached to the shafts. First the 2hp 3600RPM Emerson, that I got for the HMG "New Jersey". That was
my first experience with VFD and when I bolted it down to a massive wb, hooked it up , no load on the shaft and it started vibrating,I figured this is the way it is supposed to be and hoped that when I attach the driving pulley to it and bolt it down to the bench, the vibrations will diminish to where I won't mind it. Also I thought may be motor is to be blame.

Although I bought both of them brand new from Grainger and made sure they both are "inverter duty" rated.

So, 3 or 4 weeks later I got me 9x20 lathe and started thinking about converting it to the VFD, using the KBAC I had. So I bought the second
motor, this time 1.5Hp 1750 Dayton. Bolted it down to a WB, BY ITSELF, no load. Hooked it up to the VFD (after changing HP setting to 1.5HP) - it vibrated even worse ! Clearly it was totally not useable for a lathe!

I reached out to folx and asked if it is normal with VFD, was told: ABSOLUTELY not. It should be smooth as silk . I tried loading the shaft
of 1.5 HP with a chuck off my 7x14 - same story, really bad vibrations that
only disaapeared at the highest RPMs (1750 for this one).

So I called the KBE, had 2 separate guys listen to both motors (to answer possible question: ONE at a time, the KBAC is wired with L14 female and motors both have L14 males).

Off the bat they heard them vibrating and told me something is wrong. By that time I had checked the wiring about 1000000 times. I rechecked it AGAIN. I measured the line in (AC), the rectified voltage (DC) with KBE guy on the phone and it all checked out.

Now, the motors are in perfect balance and if I spin them up to full RMPs
and then CUT OFF power to KBAC, they instantly loose all and any vibrations/noises they are making with KBAC and all I hear from them is
slight hiss as they coast to stop. No vibrations of ANY SORT.

So yes, I am a frugal dude and do have duct tape on my 11" contact wheel.
Yes, I build my own grinders - 2 by now. Loved 1st, loved knifemaking and upgraded to 2nd model - that I modeled after Bader/KMG. Used the money I saved to order 2x2, 2x3, 2x8 polywheels from SunRay .

But, this has nothing to do with the problem @ hand, as the KBAC makes
the motors go crazy w/o anything being attached to them. 2HP by now
has a well balanced 5x2 driving pulley (bought from SunRay, I didn't have
the 9x20 then and could not turn it myself). Same story - it vibrates.

On the 1.5HP motor, I tried a chuck from 7x12, that I KNOW is well balanced, as I routenely spin it @ 1500 rpms on the lathe. Same story - it vibrates.

Now let me qualify vibrations: it is really more of "beats". May be 3-10 of them
every second, depending on RPMs. REALLY powerful beats - they shake a 400LB workbench !

So ... the 1.5HP motor went back to Grainger. Full refund, 0 hassle.
2HP stays attached to the grinder.

For vari-speed conversion of my new 9x20 I ordered a DC motor and controller
from SurplusCenter. I simply have no trust in VFD anymore, although I know
thousands of them are used for lathes/mills around the world. If I could dump the KBAC at not too great of a loss, I will probably spring for Toshi, LG, etc, NOT KB.

Still there is a 1 in 1000000 chance that there was a piece of debri inside of the case that was shorting something. Now, as the motor bounced through
FedEx, it got shaken out and now it works. Lets see if I am that lucky :D

The motors both were wired for "LOW VOLTAGE" :
- T4,5,6 tied together and left hanging
- T1-T7 is attached to one of the output legs of KBAC
- T2-T8 - 2nd leg
- T3-T9 - 3rd leg

Ground from breaker panel is not fused, goes to the ground "green" lug on KBAC and from there, another wire goes to the motor's body, grounding it
as well.

If I swap any 2 "output" legs on KBAC, both motors reverse. I tried about every POT, every jumper in the KBAC, to no avail.

The KBAC is 15 feet of 3x12 gage wire away from breaker panel.
Motor is 4 feet of same gage away from KBAC
 
Bummer!.. That must be sooo frustrating.

Were do you live? You are welcome to come to my shop with your motors and drive...we can mix and match with other stuff that I have here and maybe get you back up and running. I'm in Columbus, Ohio.
 
Man, this sounds like a Camco Vari-Pak dc controller that I have that operates at 30 cycles per minute. It "pulses" at all speeds, and it varies with the amount speed applied thru the controller. The slower CPM's cause it to vibrate a certain amount. I am able to use it for a disc grinder with the motor bolted to the work bench.

My KBAC-27D doesn't operate anything like the DC controller or like what you are describing. It's also 2HP 220V like yours. I'll keep thinking to see if I can come up with anything to help you.

I wouldn't jump the gun too fast to get rid of it. it may be something minor.

Kelly
 
Hello Rashid

I have only ever seen oscillations in a motor as violent as what you have described once. I had a prototype motor controller with one of the output current sensors wired in backwards. I doubt that is your problem since your first post in this thread, seems to indicate that your drive was sent back to the manufacturer and it tested good there.

I took a look at the KBAC series manual and have several suggestions.

1) Shake the VFD to hear if something is loose inside, as you suspect. I doubt it since a loose metal part is more likely to cause a big bang than a strange mode of operation.

2) Set all the pots and jumpers to the default positions shown in Figure 2 on page 9. I have had "strange combinations of settings" cause bizarre forms of operations.

3) Try with the motors running with a small load, ie. with the grinder belt on. The control algorithm used in the software may be having trouble with a low load condition.

4) Check the integrity of your ground connection between the chassis of your drive all the way back to your breaker panel. If you have access to a ground tester or know of an electrician with one, use it to check the quality of your ground connection.

My gut feeling is that you most likely have a bad ground connection. Any sort of motor drive (AC or DC) will inherently generate large quantities of high-frequency electrical noise. It takes an experienced and talented designer to keep the noise in control so the drive does not adversely affect the operation of other equipment and the drive itself. One of the fundamentals of keeping the electrical noise under control is to have a good ground. A ground that may work acceptably for low frequency loads like your oven and bandsaw may not be adequate for your drive. You may have problems getting your new DC drive to work properly, if the ground is not good.

It would probably be best if you state what town you are in so that someone with some experience with that drive could have a look at your setup. They may notice something that you have not mentioned or feel is insignificant.

Phil
 
Phil -

- before I even got the 1st motor hooked up, I spent plenty of time going through the manual (with plenty of excitement ! :)
- I knew that most POTs were in factory-set position and didn't change any
of them, 'xept jacking up Accel/Deccel POT a bit, to acount for higher inertial
loads
- I triple checked the ground when I first ran the 220V circuit, as I knew that w/o it one can get hurt badly, with 2 hot legs of 220V.

The DC motor I got for my 9x20 is working like a champ - I already completed
the varispeed conversion. I kept the original pulley arrangement (AAMOF I removed the original motor+pulley+electrical box as one unit and no new holes
were drilled) and now I can have something like 10RMP on the spindle with simply insane amt of torque. It stops on a dime and reverses as quickly ! Great for threading and tapping.

I should have the drive back in about 2 days ...
 
Rashid

I would suggest turning the accelleration pot to the minimum position and giving it a try again. With the accelleration at maximum, it would be much like connecting the motor right to a three-phase supply, with no ramp up. Under such conditions, a three-phase motor can draw currents that are 6 to 10 times (or more) the current that it would draw with full load, at normal operating RPM. This may be causing your drive to go into a current-limiting mode. It may also be causing the DC bus voltage, inside the drive, to collapse. Both have the effect of "backing off" the power to the motor. The drive recovers, then reapplies full voltage, the current goes up and the cycle starts again.

What did you do to check your ground? It is the quality of the electrical connection that is important. Is there any paint on the chassis of the drive where the ground wire goes (should not be any)? Are any of the connection points corroded? What about the ground connection to the panel? There should be a copper earthing rod for your house, often near where the power feed enters the house.

Phil
 
Phil -

it comes from the factory with accel/deccel timing in .5 of sec range. I changed to be @ 10 o'clock for about 5sec for both, as per manual. Thinking
wuz that having a 11" OD grinding wheel is quite a bit of inertial load and
I didn't want the drive to go into too much labor trying to speed it up or
deccelerate it on a dime. This worked just fine - it WAS taking that long
to speed up and slow down.

The inside of KBAC has a ground lug, seemed to be OK upon visual inspection.

The wiring is all brand new ... I hope to have the drive back tomorrow and then it is praying for miracle :)
 
Got the thing back from the KB Electronics . Hooked it up to the
2HP 3phase 3600 Emerson, removed the driving pulley off the shaft.
In other words, NOTHING on the motor's shaft.

Turned it on .... the shakes are back :barf: ! With vengeance, whole workbench shaking as badly as it did before. Pulley back on, shakes have diminished but still there.

Rechecked wiring, ground connection, wiring inside of motor's breakout
box. Eliminated the 220V extension cord (3x12 gage, 15f), plugged right
into the outlet (1f of 12gage to 2x20A breakers, 200A service). No effect.

I have my lathe wired with DC drive now. No way this VFD could've worked
with it. Frankly, I dunno what to do with the drive @ this point. Would not
be fair to sell this turkey (the KBE sez nothing wrong with it, after I RMAd
to the factory) to an unsuspecting guy.

Writing off $300+ I spent on it is plain stupid. Arguing the case with State
Electronics where I bought it from about 45 days ago is moot, as the factory
have not found anything wrong with it. :mad: :mad: :mad:

To those who won't bother reading preceeding stuff in this thread: I had 2 different make, HP, RPM, brand new motors and this controller does it to both
of them. With or w/o load on motor's shaft.

So here's the moral of story, from the guy that has wasted $300+ and countless days: DON'T buy stuff like this from Internet, unless you are
101% sure they will support it. And pay for shipping BOTH ways. And have
inventory to replace stuff on the spot. And have "customer's always right"
attitude. And will return all of your money if you're not 100% satisfied.



Pay extra $20 and get it from a local dealer . So when something like this happens, you can pick up the drive AND the motor, show up @ location and show the problem and get it fixed.

I would never buy anything from KBE again. Fooled me once.
 
Rashid,

Sorry to hear your drive is not working out for you. What do you want out of it? Maybe we can work a deal.
 
If anyone wants it, PM me yer best offer. Will need to see how the finances work out. If they do, I will spring for a Teco from local source .
 
Rashid

Where are you located? If you are in or near Houston, I can do a quick check of your drive at work since they manufacture such stuff here. Otherwise, I would suggest seeing if someone on the forum here lives near you and see if you get the same problem there.

I asked some of the guys here at work that design VFD's. They said that it is possible to get "torque ripple" if you are trying to run at very low speed with very light load. Try turning the acceleration pot up to get quick acceleration. The only other reasons they can suggest are a bad motor or one of the three output phases is bad. If you have a meter, disconnect the wires from the output of the drive, turn it on at full speed and check between each of three output terminals (U to V, V to W and W to U). All three voltages should be about 220-230Vac and should match each other to better than 5%.

Best of luck.

Phil
 
Rashid! As far as I am an electrical engineer and design different control devices I might be able to help you. If you still want to continue. PSO is possibly right. It might be unmatched motor and control propeties. I was actually very surprised that some company produce VFD just for "electrical motor". Normally(I would do so) the controller is designed SPECIFICALLY for the sertain type of motor. In the PID(as it sould be made) the motor rotor mass, inertion, torque, desirable acceleration and all stuff like that is MATCHED and takes part in calculations.
I know it exactly because currently one of my progects contains electrical motor and it has a feedback loop. It works so-so unless I match most of parameters! I can not understand how one can build so versatile controller just for "any motor".
It is possible that VFD you've got are designed and tuned for sertain motors even when sales person tells you it'll work with your particular motor. So I am not surprized with your sad outcome.
If you have access to PID variables in the controller you can try to tune it. Otherwise... I'd giveup. it is very hard job to reverse engineer somebody's device in order to modify it. For production design is usually striped so lean. Only nesessary components. No trimpots no trimpoints.
 
Folx,

thanx for support.

Dmitry - as I was going through ~100 page manuals for true programmable
VFDs over last few days, I did see number of PID-related variables and started questioning the same thing: how can one set these up to where any motor is magically "tuned". To compare: outside of may be 8 trimpots and some jumpers, there're no way to change anything in KBAC unless one springs for programming kit. And even with that I am not sure what is tunable.

On the motor and wiring: I ran it with 2 dift motors, make, model, HP, RPMs.
Same result with both. I am NOT :mad: rechecking the wiring, not for 10001
time :) It is all legit.

It vibrates the worst @ 50% of HZ/RPMs. It literally shakes my WB - you can see benchtop move may be 1/4".


PIDs require some form of feedback. In VFDs, what would they use for it ? There's no tach or servo-like encoders
on the shafts ...
 
Well..., you gave up?

Than you need to relax and look here
by the way.

If you can send me a link to the manual or description of this VFD I possibly can look through and have some ideas... if you did not give up...
 
On a funny note - today's wuz just not "my day". Overslept :), brought kid late to school, crazy day @ work. Came home , started turning beefed-up
compound mount for my new 9x20 and guess what ...

my DPDT On-off-On switch from RatShack that I use to change direction of DC motor, SHORTED the 2 poles ! Sickening electrical noise, smoke, blackened wires. I had a 15Amp fast acting fuse in there and it blew.

Yanked the switch out, hooked up the motor directly to the Minarik drive,
new fuse in. Much praying ... power on ... whatta relief ! It works fine.
Thing's built like a tank !
 
Yreaman! Got the guts and grabed the luck.
About the feedback for VFD. Some designs use the motor current to decide waht to do. But you are right, tacho should be on. In some devices they use the shape of the current and stuff like that. It is to avoid patent royalties. The best way IMHO is to have tacho and current and voltage measured constantly. And I would prefer analog device tuned for the particular motor. Digitals are able to "learn", but it depends on what chip is inside. Learning are pricy.
If you turn the motor on at 50% duty cycle and wait a bit is anything changing? Is vibration changing? It might need some time to collect enough data to set the proper values for PID. Again, I do not know what's inside your box exactely...
 
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