Break sensor adjusment for Lithrone 540

[komori92]

Hello, we had an issue with a break relay and after we changed it, the machine isn't stopping on positions where it's supposed to stop,for example when changing plates with ACP it stops 10 cm earlier then it should. If anybody know anything please write to me.
@CHOCK if u can please answer me I really appreciate your help.

 

[Paul Bradley]

Hi Is the brake working correctly? when doing an APC the press should be on crawl and the varicam decides when it should stop so the brake should not cause a problem.

 

[komori92]

Not sure if its working correctly because sometimes when we try to run machine it doesnt want to start, after couple of tries or sometime restarting the machine it starts again.APC is playing the melody and then after first position it doesnt move anymore but it doesn't stop on correct positions for changing?
Any help would be appreciated

 

[komori92]

We have changed this relay, it is not original part bit has the same specifications lake the one that was mounted on the machine.
Maybe that could be cause of a problem ?

 

[Paul Bradley]

The position to stop during APC is done with the Varicam and encoder you may need to check that the varicam display reads 00 when the press is at its zero position Your picture shows a tachogenerator not a relay.
You need to get the press to run normally start , stop , inch etc check that the brake is releasing before the motor tries to run

 

[komori92]

Sorry for the mistake, but can you please tell me more how to set my Varicam, and how to know where us zero position for a machine?

 

[Paul Bradley]

Hi
It is unlikely that the varicam has lost its position. the zero point of the press may be on a dial on the operators side of the first unit, there may be a small window you can see it. If not remove the cover operators side first unit there is a hole in the gear that lines up with the casting behind. The easy test run inch the press the zero point is when the swing arm grippers come forward about to grab the sheet, so the varicam should read 000
There should be a sheet of paper with the varicam settings where the varicam is below the operators panel.
What model is your Komori?

 

[komori92]

Hi
It is unlikely that the varicam has lost its position. the zero point of the press may be on a dial on the operators side of the first unit, there may be a small window you can see it. If not remove the cover operators side first unit there is a hole in the gear that lines up with the casting behind. The easy test run inch the press the zero point is when the swing arm grippers come forward about to grab the sheet, so the varicam should read 000
There should be a sheet of paper with the varicam settings where the varicam is below the operators panel.
What model is your Komori?

So what can be the other reason for APC not to work, if It is not varicam, cause It loooks like varicam is on right position when I checked under first section.
But when I run APC it doesn't work, it plays the melody and after first wrong stop it won't continue.

 

[komori92]

We had the technician coming to change our tachogenerator and after that we started having issues with APC and machine running at all. He was making adjustment on parameters that are onw the pictures below without I think knowing what he was doing. Can that be an issue?

 

[Paul Bradley]

Does the press run on inch and crawl at a steady speed and does it speed up ok?
When the press stops for APC what is the reading on the Varicam is the position too small or too big?
Is it the same on all units or just the first unit?
I suspect that the issue is with the main motor drive, as this was the only thing that was changed, maybe the APC speed is too high and it is over running or there is a problem with the brake or brake gap?
What was the original problem before you replaced the tachogenerator.
If the new tachogenerator has a lower output voltage this will make the motor run faster. Check the brushes on the original tachogenerator.
Also check the brushes on the main motor, this could cause speed variations.
Good luck

 

[komori92]

Does the press run on inch and crawl at a steady speed and does it speed up ok?
When the press stops for APC what is the reading on the Varicam is the position too small or too big?
Is it the same on all units or just the first unit?
I suspect that the issue is with the main motor drive, as this was the only thing that was changed, maybe the APC speed is too high and it is over running or there is a problem with the brake or brake gap?
What was the original problem before you replaced the tachogenerator.
If the new tachogenerator has a lower output voltage this will make the motor run faster. Check the brushes on the original tachogenerator.
Also check the brushes on the main motor, this could cause speed variations.
Good luck

Yes it runs on inch and doesn't crawl at steady speed, it varies from 3800 to 4100 .
Reading on varicam is to small it shows 59 and on paper sheet it's written 224.
There could be possibility of a problem with a break gap, can you explain how to set this gap ?
It is same on all units when running APC.
We ll have to check for brushes on main motor.

 

[komori92]

Is it a issue if it shows 283 and on varicam is 285 very small difference. And how can I know how to set this parameters back to original.?

 

[Paul Bradley]

The first you need to do is get the main motor and press to run at a steady speed.
What was the original fault with the press?
If changing the Tacho changed the fault symptoms then put the original tacho back on and diagnose the original fault.
another cause for speed variations could be loose or worn belts or oil on them.
Also check the current into the motor is this varying. Again check the brushes on the motor.
The motor drive uses the output from the tachogenerator as feedback to maintain a set speed of the motor. Your electrician needs to do some voltage and current checks.
I would not change the Varicam settings as these are probably correct, the press is not stopping in the correct place and the varicam confirms this by not continuing with the APC. if you move the press to where the varicam has the correct reading you should see that the plate clamp lever is lined up, if this is the case then the varicam readings are correct.
Again address the original fault and you will most likely solve the APC issue.

 

[Paul Bradley]

Can you send me the pages from the circuit diagram with the main motor and drive with the preset speed settings?
This may help with the diagnosis

 

[er.bajaj001@gmail.com]

Hi,
I would like to Know which Relay your Changed,

Mayank Bajaj
CEO
Bajaj Engg.
+9181066-66607

 

[komori92]

The first you need to do is get the main motor and press to run at a steady speed.
What was the original fault with the press?
If changing the Tacho changed the fault symptoms then put the original tacho back on and diagnose the original fault.
another cause for speed variations could be loose or worn belts or oil on them.
Also check the current into the motor is this varying. Again check the brushes on the motor.
The motor drive uses the output from the tachogenerator as feedback to maintain a set speed of the motor. Your electrician needs to do some voltage and current checks.
I would not change the Varicam settings as these are probably correct, the press is not stopping in the correct place and the varicam confirms this by not continuing with the APC. if you move the press to where the varicam has the correct reading you should see that the plate clamp lever is lined up, if this is the case then the varicam readings are correct.
Again address the original fault and you will most likely solve the APC issue.

Sorry for not replying earlier, we still have an issue. We can not keep it running on stable speed.

It runs on 3500, then 3700, 3600, 3500, 3700 and it changes every two three seconds.

But if we increase the speed than it doesn't change, it keeps it stable.

 

[komori92]

Does anybody knows how can I set this ?

 

[komori92]

Hi,
I would like to Know which Relay your Changed,

Mayank Bajaj
CEO
Bajaj Engg.
+9181066-66607

We changed tachogenerator.

 

[Paul Bradley]

Hi what was the original fult before you changed the tachogenerator?
Does the voltage to the main motor armature change with the speed changes?
Does the voltage from the tachogenerator change with the speed? this should vary as the speed changes as the voltage output is a direct reference of speed
Have you checked the carbon brushes on the motor? The commutator should be a nice smooth chocolate brown colour
Is the current into the Field windings constant? this should stay constant at any speed
Is the voltage from the speed preset speed setting stable?
It is possible that you have a faulty SCR that is not firing this can be checked by measuring the current in each arm of the SCR bridge

 

[komori92]

There was no issue before we changed it, once we had problem with it ,and after replacing when we run the machine the problems started showing.
Yes, when we do measuring at the outputs on lower speed it varies its not stable , once you get it over 5000 rpm it's stable.
We did not check the brushes yet as the electrician said that it can't be from it and he is looking everywhere else except changing them.
We ll have to check and measure this, but can it get damaged from broken tachogenerator?