Help with Siemens SIMOREG Drive?

I'm having some problems with a siemens drive in a payoff we have on site. This was baught 2nd hand from a 3rd party who we can't get in contact with.

The drive is a SIMOREG 6RA24 connected to a 240V 37Amp motor.

What happens is that the drive trips out with error F038.

Looking in the manual it says

This fault is activated if the speed actual value exceeds the level set with paramater P354.

causes:
Current regulated drive
P354 set too low
Intermittent tachometer cable connection

Well, the drive must be in speed control as it's a dancer controlled payoff and it's also under armature voltage feedback mode. P354 is set at 120% which is it's maximum.

This problem has left me stumpted as i have never worked with a Siemens drive before. Can anyone give me a gem of knowledge?

Guessing from your description alone, it seems that there is something wrong with the speed feedback (tachometer or "dancer" or ..). It indicates that the drive speed is to high.

Maybe you cant get in contact with the seller of the drive, but Siemens should still be helpfull, give them a ring.

Xion

Parameter 354 is the overspeed setting, you say that it is set to 120% of full motor speed.

Check parameter 317, that is the maximum speed setting, see what that is set at.

Is this the first time that the drive has been run on your motor? Or has this fault just started to occur?

I would check the parameters P100 to P103 and ensure that they match the details on the motor rating plate.

Also if this is the first time the drive has run the motor, did you run the drive through it's 'optimization' run.

Paul

Thanks for your help.

Both P100 and P101 were correct when i checked them. This drive has been running this motor for just under 1 year, this problem has occured rarely in the past, maybe once a month but now it's 3/4 times per hour.

P317 is at 100%, do you think it's worth reducing this?

The drive is in arm feedback mode

Xion said:

Both P100 and P101 were correct when i checked them. This drive has been running this motor for just under 1 year, this problem has occured rarely in the past, maybe once a month but now it's 3/4 times per hour.

P317 is at 100%, do you think it's worth reducing this?

The drive is in arm feedback mode

Click to expand...

Were P102 and P103 (field settings) correct?

Personally, I wouldn't reduce any settings just yet, I would look into possible causes of the overspeed. I realise that if this is intermittant then there could be a problem finding it.

The only way to 'overspeed' a DC motor is increasing the armature voltage or weakening the fields. A momentary loss of field current will cause the motor to 'run away'

I would have a look at the motor and measure the fields for the correct resistance.

Does the motor run in both directions?

Does the overspeed only occur in one direction? If the fault only occurs in one direction, is the brush ring set in the neutral point.

If you can't find any obvious reason for the overspeed, them maybe reduce the armature voltage slightly, or maybe up the field current by a little this will also slow the top speed of the motor down but will increase the torque slighly.

Paul

What is P83 set at?
What is P115 set at?

What value is P25 reading (when running)?

Have you checked the feedback signal from the dancer? If the drive is trying to follow a noisy or intermittent signal, that could be causing the overspeed.

Have you been able to observe the operation of the line when the fault occurs? Have you talked to the operators to see if they have noticed anything unusual going on? When the system works correctly, most of the time, you need to be careful when you change parameters. You could wind up degrading the performance under normal operating conditions. Best to identify the abnormal conditions causing the fault.

Thanks for all of your help... I'm looking into the many suggestions. The motor looks fine, brushes fine, field has tested out ok. The dancer pot tested ok. I'll look into the other suggestions...

When the drive faults, does the motor coast to a stop?

Sounds like a bad bearing or wire within the tachometer, Maybe?

There is no tacho...

This might sound like a dumb question but..

What is a "Dancer"?

John

Sometimes called an accumulator. Basically it's a pully on an arm of some kind that can move. A machine pulls cable through this pully and therefore moves the arm. This arm position is fed into the drive on the payoff so the payoff runs. The payoff is normally under PID control to keep this pully arm in a central position.

This means a payoff can be under it's own PID control seperate to the main machine.

Xion,

What is P83 set at?


What is P115 set at?

What value is P25 reading (when running)?

Look at sheet 10 on the function diagrams- Are you using the Tech. Controller?

In armature feedback, the actual speed detection is calculated, not measured. For this reason, it is essential that the motor be properly tuned to the drive. That would include the current minor loop, a field regulator and armature tune function. All of these must be completed in order for the calculation to come out properly.

PLucas states that P354 is an overspeed trip setting in % of full motor speed. I would think that this would be % of maximum speed. Otherwise, only 20% field weakened overspeed would be possible.

I am not real familiar with the Siemens products but, as a rule, drives running in armature feedback are not capable of running overspeed. That would require closing the speed loop with a tach or encoder. If overspeed is not allowed in armature feedback, then, as mentioned before, low field current or high armature voltage would be processed by the drive as overspeed.

It may very well be that this DC drive does not have an input isolation transformer and is therefore seeing AC line noise as overvoltage. This would explain the random nature of the faults.

DC drives are much more sensitive to noise on the AC line and a transformer is always recommended. This would be a good way to clear up input voltage problems, as well, assuming the transformer has +/- taps.

At least consider 5% input line reactors if an input transformer simply can't be done. They won't correct voltage problems but will deal effectively with noise.

JNelson asks:

This might sound like a dumb question but..

What is a "Dancer"?

Click to expand...

A dancer is usually an arm or roller that some material runs over. There are many varieties of dancers but a standard involves using an pneumtic ram with a specific amount of air pressure to create tension against the product moving across the dancer arm/roller. The dancer arm/roller is connected in some way to a potentiometer, transducer or some device that can give a "position" using voltage or current. THIS is one of those 4=20ma, 0-10vdc, etc...analog inputs used in plcs...they are also used with drives.

What happens is when their is slack in the product the dancer "rises" and the signal to drive (in this case) tells it to speed up to create tension...if this was a 4-20ma device then the standard signal would be around 12ma (dancer should be midpoint in travel normally), any signal above that would make the drive increase speed. If the dancer arm/roller "lowers" then the signal would be below 12ma which would make the drive go slower...to decrease the tension on the product.

I use to work in a plant that had printing presses (made xmas paper). They had 2 kinds of presses but that is irrelevant...all the presses had what was called "unwind" and "rewind" sections. Imagine a roll of toilet paper thats 36" wide and 50" in diameter, these were mounted on rollers to "unwind" the paper fed to the press. The press needed to run continuous so they "splice" the new roll of paper to the old roll while its running, to do this they need to make sure they can match speed of the roll to the press. The dancer is used to set the speed of the "unwind" to work with the press. There is also a similar process for the "rewind" of the paper at the finish end of the press.

Hope this helps.
NOTE: this was a simple explanation, the actual values of the potentiometer, transducer etc could be reversed or ?. The actual procedure and components may vary depending on situation..basically a dancer is a "term" used to describe a feedback device used in a specific type application. The feedback device normally travels up and down in an arc with standard position being midpoint but when running it will kind of oscillate up and down...ie it dances.