Main Motor Error

[Richie]

Hie guys am running a Komori LS440 and am having problem with the press. It all started when i was inching on the 2nd unit, the machine just went dead. It wouldnt inch or run & on the touch panel(control panel) on the console it was saying main motor error. Called an electrician he told me to press the reset button in the main switch cabinet & the problem was gone. The main motor error is now a daily thing @times during the run the machine just drops speed to crawling on its own and stops, main motor error appears. We had the machine checked but everything was ok according to the electrician but we still have the problem. Each time we have it we reset but am now worried about reseting everytime. Has anyone had this problem &how did you sort it out.

 

[RichardK]

We had a Main Motor Error (L626 - 2001), our turned out to be the electromagnetic brake air gap that needed adjustment.

A competent Komori mechanic should be able to reset the brake air gap in around a half hour.

Good luck

 

[Richie]

Thanks Richard will try get someone look at that.

 

[klecman]

At the risk of belaboring the obvious, check your main motor air filter and the incomming voltage to the press. The
AC voltage should read between 210 and 230 volts phase to phase while the press is running at printing speed. Measure the voltage on the motor side of the main motor contactor. Also check the continuity of the auxilary contacts on the main motor and blower motor contactors. Do this with the power off and the contactors manually pressed in. You should see a steady reading of less than one ohm. If the reading is above 1 ohm or not steady, try cleaning the contacts with a good grade of cleaner such as CRC brand QD contact cleaner.

 

[tonythetiger]

the fault is with the main motor encoder

 

[Meny]

Richie - call Kemtek , they will give you the needed solution whatever it is.

SIMPLY call kemtek. they have the knowledge and the will to solv all Komori problems and if they have no answer , they have Komori UK / Europe to call.

It is better to get it right at once and not waste time on T&E

Do you have Kemtek number ?
your location ? JOBURG ? KAPE ? DERBAIN ?

 

[klecman]

The main motor encoder is certianly a possibility but I wouldn't recommend changing expensive parts unless you have a specific reason for doing so.
Next time the problem occurs, look at the LED panel on the main motor drive. It should display an error code that may be found in the drive manual. If you don't have the manual, let us know the model of drive you have and the error code. I will see if I have any information on it.

 

[tonythetiger]

the reason is that the press will not run correctly

 

[klecman]

That's not specific enough to lead me to conclude that the encoder is at fault. There are literally hundreds of possible faults that could cause the monitor system to show a main motor error. As Richard said, the brake adjustment is a more likely cause, in my experience, than the encoder. Now if the motor controller error code corresponds to "encoder error" then we whould have specific reason to suspect the encoder. I have adjusted the brake far more often than I have had to change encoders. I would also want to observe the encoder signal on an oscilliscope before concluding that it is malfunctioning.

On one job, where the customer was experiencing a main motor error, they were told that the controller or encoder had to be changed. The waveform from the encoder was clean and steady so I opted not to change it. We found an autotune function in the controller manual and after performing that, the error no longer occurred.

 

[tonythetiger]

I have 3 presses, a LS1040p,LS840p and a LS640. All have had the same fault and it has always been the encoder.it's a common fault.

 

[klecman]

Good point. My experience has been different. Over my last 5 years of repairing Komoris, I changed only a few encoders. One motor error indication was caused by a loose drive belt and two by glitches in the drive that were corrected by resetting program parameters. Some others were due to low supply voltage.

 

[Richie]

the error codes it usualy gives are 1,o5 1,ot & 1,oU depending whether i was inching, idling or printing.

 

[klecman]

I cannot find error code o5 in the VF-61 manual but
ot indicates over torque
ou indicates either a faulty "close" signal between terminals 24 -18 of the inverter or a faulty GAC61 circuit board.
About all you can do by yourself is to see if the current drain of the main motor is higher than normal.
Otherwise, you will need an experienced technician to troubleshoot. Try to find one who knows how to autotune the inverter as I have had luck doing that.

Error codes are often meaningless so the problem still could be in the encoder but at least I would want to try an autotune first. This will require disconnecting the drive belt. I'll look to see if I can find the instructions but they should be available from Komori.

 

[Richie]

Thanks guys had said error code 1,o5 think it should be 1,oS.

 

[klecman]

oS is an indication for over speed. The manual indicates that it may be due to a faulty setting of the parameters in the inverter. Try to get a copy of the new manual and a motor specialists.

 

[klecman]

There are some downloadable manuals on
http://www.drivecon.com/manualsdiscontinued.htm
About 3/4 down the page

 

[tonythetiger]

It's the encoder!!!!!!!!!

 

[klecman]

Yes, the multiple error codes do suggest an encoder problem. I would like to see the output waveform on a scope though. If the signal gets irratic just before shutdown, that would help confirm it.

 

[tonythetiger]

just change it as I suggested 7 days ago.you would have been up and running with no problems by now!!!!!!!!!

 

[Richie]

Thanks guys now waiting for the engineer to come have a look at the press. With all the suggestions & information you have brought foward i hope the problem will be a thing of the past. Am expecting him next week, will let you know of the results.