Millar

Ultra 3000 faulting

8 posts in this topic

I have recently installed an ultra 3000 sercos drive and an AB servo motor coupled by belt to an Exlar cylinder.  The application is setting a Planer head to Position and hold.  The application seems pretty simple but every once in a while When attempting a move the axis will get a FEEDBACK , FEEDBACK NOISE, MANUFACTURE SPECIFIC FAULT and will not reset.  I have watched a trend while resetting and the Torque feedback goes to max.  One would assume the axis is jammed but can be moved quite easily by spinning the Exlar by hand.  If the Torque is at max why is the motor not turning??  I have changed to another Ultra 3000 , tried different cables, and changed the motor.  It will work fine for awhile and then give us trouble again.

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It sounds like the servo drive is seeing a lot of torque, probably at the start of motion.  Have you tried to model this setup in Motion Analyzer (FREE).  I have run into similar situations in which one has to model what the mech engr designed to prove to them that yes, there is a problem.

If you changed hardware and the drive is still exhibiting the problem, the problem is reality...this motion solution sees a high amount of torque at some point.

Motion Analyzer may be daunting on first try.  This work instruction may guide you through mocking up an application.

Work Instruction - Allen-Bradley Motion Analyzer Software.doc

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Thanks - I will get the analyzer installed and give it a try but Im not sure that the problem is reality since i can move the axis so easily by hand while this fault is occurring.  The axis will fault when trying to move in either direction.  The motor has no problem moving this equipment for weeks - then i get this fault and lose a lot of production time.  Thanks for the suggestion.

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We had a machine years ago that when it faulted it would do an emergency stop quite hard and that would free the jam on the ball screw so that when the fitters checked it out it moved freely, we ended up putting a chart recorder on the motor to show the fitters that the torque current kept getting higher until it tripped the drive and shut the machine down and clearing the jam.

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Check encoder cable shield has a good connection inside the connector at the drive end.

Sometimes it pays to wrap the shield in copper foil tape to increase the surface area for the clamp. This will help in reducing the noise.

Do you have a spare motor and encoder cable to try? 

Try ruling out one of the above.

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I have actually tried a new drive, new servo motor, different exlar cylinder, different cables.  Pretty much have changed every component at some point.  Managers are losing faith and wanting to go back to the old hydraulic motor on a screw jack - gotta figure this out.  Thanks for the replies and suggestions

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Does the servo motor have a brake installed ?

I have to ask, but has it been tuned for all of the motion move profiles you are trying to achieve? 

Whats the part numbers of the motor/drive and exlar actuator you have?

Edited by Donovanr

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Are you using AB factory servo cables all the way for both power and feedback?  We had a baldor servo motor that had 40' of cable between the drive and the motor.  It was using THHN wire from the drive to the enclosure next to the servo motor, and then a servo cable for the last 6 feet.   We upgraded to an AB ultra 3000 drive and AB servo motor and it would run fine for an hour then give us all kinds of crazy encoder errors.  An AB God told us we had to have the servo power cable the full run, and when we swapped it out the problems went away.

 

 

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