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Fadal 4020a spindle shuddering, fluctuating speeds and going backwards to commanded direction

static99899

Plastic
Joined
Jan 14, 2013
Location
Decatur, TX USA
I bought a used 1996 Fadal 4020a with the 15hp 7500rpm rigid tap spindle. As the title says, if I command an M19, sometimes it orients and most of the time it does not. If I command S1000 M3, it turns CCW at about 55 rpm and has the spindle load meter pegged at 150%. It never errors out, so I hit the spindle stop button and sometimes it stops, sometimes is shudders CW and CCW until it stops and sometimes it continues to spin at about 30 rpm.

Those are the symptoms and now I will list what I have checked or replaced; in the order I replaced/checked them. Please note, none of these have made any change at all:

1) verified voltages incoming were correct, and balanced within 5 volts. This was checked at the transformer, and at the spindle inverter.
2) verified and added addition machine ground to earth ground rod
3) verified DC voltages coming from power supply in control cabinet.
4) Checked encoder cabling for shorts with meter, none found
5) unplugged encoder, it runs at the correct rpm for 3 seconds the says "motor overload" and shuts the spindle off (so it sees the encoder feedback is missing when unplugged)
6) since I don't have an oscilloscope, I replaced the US digital encoder
7) swapped 1010-4 spindle card for a known good 1010-4 spindle card
8) Bought a battery box from cncpros to directly test spindle drive, drive failed the tests due to still having the issue after bypassing control cards, so...
9) bought a brand new Glentek spindle inverter, and the problem persists! (mode 1; 15hp 7.5krpm sensored)

So I did try to operate the spindle drive in a mode that doesn't require the encoder input and it will work perfectly in this mode. It spins at the speed given by the battery box and turns the correct direction. On this setting, it's the wrong rpm for my machine(15hp 10krpm VFD), so I can't leave it there and I'd like to retain my rigid tap feature, so this is not a good permanent option.

Neither the original Baldor drive nor the new Glentek show an error of any kind. Both display the wrong rpm and direction of the actual motion.

I'm running out of ideas and money to throw at it in parts so if anyone has a suggestion, I'd loved to get another perspective before calling the local tech out to the tune of $150/hr.

Edit: Between 6 & 7, I did replace with a brand new hall sensor for the orient and it does show it works in the DI page.
 
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Did you check the hall effect sensor above the spindle.

Can't remember how to get to it but there's a page where you can see the state of the hall effect change when the magnet goes under the sensor.

DI is I think the command

If you go to Fadal cnc they have all the manuals. There's one with all the troubleshooting steps. Or call Brian at Fadalcnc, he really knows his stuff.
 
Did you check the hall effect sensor above the spindle.

Can't remember how to get to it but there's a page where you can see the state of the hall effect change when the magnet goes under the sensor.

DI is I think the command

If you go to Fadal cnc they have all the manuals. There's one with all the troubleshooting steps. Or call Brian at Fadalcnc, he really knows his stuff.
Yeah, I updated my original post to include the hall sensor. It was late last night and I forgot to add that lol. I do plan on calling fadalcnc today and I'll definitely ask for Brian. Thanks.
 
Does that machine have the low/high speed contactor?

Mine is a 10k spindle and has the high low belts, so no first hand experience with the setup you have, but like mentioned above I would call cncpros or ITC, both have helped me over the phone figure out the issue and got me the parts needed to be up and running again. .
 
Does that machine have the low/high speed contactor?

Mine is a 10k spindle and has the high low belts, so no first hand experience with the setup you have, but like mentioned above I would call cncpros or ITC, both have helped me over the phone figure out the issue and got me the parts needed to be up and running again. .
It has a single belt setup. There are two contactors that switch between WYE and Delta configuration for the speed changes. They seem fine but I'm not sure how they should act for sure.

I'll definitely call cncpros 1st since they are the ones I bought the spindle inverter from. I'll call Dan at ITC if they can't help me. He always seems like I'm bothering him lol
 
Encoder feedback issue. Id get an oscope or someone with one to check it where it hits the drive. Old encoder and replacement having the same symptoms points to cabling, or not set correctly.

Alternatively Id meg the motor windings, just to confirm thats healthy. Also make sure encoder target wheel doesnt have significant runout/damage or radial play.
 
It has a single belt setup. There are two contactors that switch between WYE and Delta configuration for the speed changes. They seem fine but I'm not sure how they should act for sure.

I'll definitely call cncpros 1st since they are the ones I bought the spindle inverter from. I'll call Dan at ITC if they can't help me. He always seems like I'm bothering him lol

Call cncpros.

Wouldn't be cool to call Dan at ITS if you didn't buy the inverter from him. Agreed he isn't that friendly
 
Encoder feedback issue. Id get an oscope or someone with one to check it where it hits the drive. Old encoder and replacement having the same symptoms points to cabling, or not set correctly.

Alternatively Id meg the motor windings, just to confirm thats healthy. Also make sure encoder target wheel doesnt have significant runout/damage or radial play.
I'm thinking it must be the encoder cables; one or both of them. Not sure how you could not set it correctly, it comes with all the spacing tools and such. I don't have a way to meg the motor but I did check the windings and there are no shorts to ground and I get an even ohm reading going across them. Like I said originally, I was able to run the motor in VFD mode and it works fine so I would think if the motors internal insulation on the windings was bad, it wouldn't work at all very well?
 
My comment will be of no help - in 2000 I bought a new Fadal 3016.
Already had two at that point that were trouble free.
So - this machine was doing pretty much the same thing as you are describing- minus the shuddering.
It would randomly go backwards when commanded to go forward(M3)
I fought this for a year - broke many cutters and wiped out a few face mills.
This machine was under warranty and Fadal factory techs flew up to try and fix - several times.
I finally put it in the parklot and told them to come and get it.
 
Don’t take this as Fadal bashing- I still own three that we use everyday, 10 hours 4 to 5 days a week.
They are slow, but reliable, and well maintained, and according to the annual ball bar - they are as good as they left the factory
 
Don’t take this as Fadal bashing- I still own three that we use everyday, 10 hours 4 to 5 days a week.
They are slow, but reliable, and well maintained, and according to the annual ball bar - they are as good as they left the factory
I get it, and I'm not a fanboy so I take no offense. They're just machines and all brands have issues eventually.

I did replace the encoder cable and that has fixed the issue of fluctuating speed and maxing out the load meter. Now the only issue left, it the spindle is spinning the wrong way for what is commanded( it turns backwards on M3 and forwards on M4) We'll see what Brian says...
 
I did replace the encoder cable and that has fixed the issue of fluctuating speed and maxing out the load meter. Now the only issue left, it the spindle is spinning the wrong way for what is commanded( it turns backwards on M3 and forwards on M4) We'll see what Brian says...
Swap two leads on the VFD?
 
Swap two leads on the VFD?
Swapping the leads causes it to run 40rpm no matter what speed is commanded. So I put it back like it was.

I tried replacing both encoder cables from the encoder to the spindle drive with factory new from ITSCNC. No change.

Weird side note: I realized that i had accidentally switched the yellow and brown encoder wires when I assembled the short cable connector so I fixed this and suddenly, the original issue is back! (Spin wrong direction slowly with a maxed out load meter)

So I swapped the wires back to the wrong way and it's back to spinning the right speed, just the wrong direction! I'm really lost as to what's going on...

I checked the DC power supply again and all of the voltages are plus about a half volt so that still seems good. I forgot to check for AC voltage on the DC lines like the Fadal flow chart says, so I'll check that tonight I guess.
 
Quick update: Still not working correctly. I thought I had it fixed after I replaced the DC power supply and reversed the T1 & T2 outputs from the spindle drive, but after a power down and reboot, it's back to it's old tricks again as if I'd done nothing. CNCPROS and ITSCNC so far don't know what is going on either. I've ordered a used 1010-6 card with the ele-0001 rigid tap eproms to try before I look at replacing the actual spindle motor. I was wondering if the backplane board could be the issue but I can't see how and neither of the previously mentioned companies think it's the issue. The board should be here Wednesday so I'll try that and see and give an update here so anyone following has the full track record.
 








 
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