1. There is no attachment.
2. Does it tripp om startup or while running?
3. Is the motor running constantly or intermittently?
4. What is the motor running/supplying?

NAFO Sergeant Anna Gr 69th Sniffing Brigade

RedSnake,

99% of the time the trip occurs when bringing up the press, at a cold start or if the press was shut off for 10 minutes and then trying to re-start the press.
It is a lube pump, so it is the first pump to turn on before the main motor is turned on, and the lube pump runs constantly.
The lube pump just pumps lube oil for the press. The lube oil is for the 2 giant servo motors, the RAM, bearings, gears, etc.

I double checked, and am sure now that there is an attachment.

• https://files.engineering.com/getfile.aspx?folder=8858eaf7-c592-4564-b390-1

One difference is that you have 20% more flow from the pump since the motors rpm is 1765 instead of 1463 which mean you will have a higher back pressure in the hydraulic system too, especially if the oil is cold, but since it trips after restart it's probably not a problem with cold oil.

If the pump or the system have any kind of pressure reduction valve maybe it isn't large enough to handle the extra flow?
Hard to say without a hydraulic drawing.
I think if you can measure the pressure in the luberivations system at startup and also the start current that might tell you if this is the problem.

According to the manuel 13.2.2 the Current limiting should be 4 and Starting voltage: 40% but of course it's just a recommendation.



https://cache.industry.siemens.com/dl/files/095/38...

NAFO Sergeant Anna Gr 69th Sniffing Brigade

You could be right about the extra load on the motor circuit caused by the higher rpm and possible oil flow restrictions, being it was designed for 50 Hz. I do not understand hydraulics very much, so I uploaded the hydraulic drawings. There are 3 of them, and it looks like I can only upload one at a time.

• https://files.engineering.com/getfile.aspx?folder=12e2697c-335f-43c2-a769-d

Here is the second file

• https://files.engineering.com/getfile.aspx?folder=15c8d3ec-6df3-41b0-8f13-2

Here is the 3rd file.

• https://files.engineering.com/getfile.aspx?folder=bfc8a287-c5bd-4bd0-b6bf-2

It looks like the system is made to be able to handle both 50Hz and 60Hz running.



Pump pos 5 ALP2-D-40 MARZOCCHI
But according to the pump manufacturer the absorbed power at 130 bar is around 10kW at ca.1476 rpm.
But as high as 12kW at ca 1765 rpm, meaning the motor is running at max at all times if the pressure is at 130 bar which you also show on your amperemeter in the photo 21.11Amp.
Even though the motor should run at max 18.8 A at 11 kW.

https://www.marzocchipompe.com/sites/default/files...



I would start by measuring all the pressures to see so that everything is set right.
You should have 60 bar at measure point 32.8
And no more then 130 bar at measure point 27.3 not even at startup.
And if you bypass the filter at pos 42 the pressure drop should be less then 5 bars at manometer 27.3 otherwise your filter is full and the filter guard is not working right.



But I think your main problem is that the the pressure limiter should be set to 110 bar or something like that so that the power outtake is in line with the motor power.
You should ask the press manufacturer if there will be a problem if you set the pressure limiter pos 31 to ca 100 - 110 bar.

NAFO Sergeant Anna Gr 69th Sniffing Brigade

Thanks for posting the drawings Red.
It seems strange that the motor nameplate shows higher max current at 50 Hz than at 60 Hz.
Intuition says that there will be more cooling at 60 Hz to possibly allow a slightly higher current at 60 Hz speed.
Just saying.
I agree with the 110 bar setting.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

With a reduced voltage is the pump even moving? Are you getting a locked rotor because there isn't enough torque to turn the pump if you still have 110 bar on the other side?

Why do have a soft starter for a 10kW motor?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

Quote:

Could it have something to do with us using 410 VAC?

Probably.
410 Volts on a motor that wants 440 to 460 Volts and a starting voltage of 40% of a voltage that is almost 10% low to start with?

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

Quote (LittleInch)

With a reduced voltage is the pump even moving?

Good observation. I agree.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

I agree with all of you, in other places in the factory, our bus voltage is 480. We are using a special transformer on this Servo press for some reason.

This press was designed and built to run in a country that uses 50 Hz. and was sold to someone in Europe who backed out of the sale and we got it at a reduced price of $7 Million.

The press is a 1500 Ton ARISA and they are in Spain. The company in America who services it is called Nidec. They are telling me that the soft starter is bad, even though I had swapped it out with another soft starter that is exactly the same and it is doing the same thing, keeps popping the over load and the one that was tripping before, is not tripping. They want to send a new soft starter, "which does not make sense to me". I do not know much about hydraulics, I am a Controls Systems Engineer, and I do not know why they are not listening to me. The voltage should be higher, then the amps would be lower. And, if the hydraulic systems was designed to operate at 415 volts in a 50 Hz country, then the RPM would be 1467 at 20.1 volts. The hydraulic drawing show that the flow and the pressure in the system is regulated. So, running this in a 60 Hz country, at 410 volts, the amps indeed would be higher and the RPMs would be around 1765 which would increase the pressure and flow. I agree with Redsnake. I am going to take some pressure readings at the points where he suggested and present these findings to ARISA and Nidec.

And to answer Littleinch, I do not know why they are using a soft starter other than to control timing, and the motor is rated at 11kW. It has to do something with the 130 bar settings.

In the last attachment that I just uploaded, the pressure in picture 4 has to be showing 1750 psi and it will not climb until we turn off the overload button noted in picture 5, which dumps the back pressure so it can rise. (at least that is what the press operator told me), and this is an unconventional thing he does to get the pressure to rise so he can reset all the lube faults and get the pressure reading to start showing in the screen on picture 3 under the collum Real.

I wish I understood more about the hydraulics. For now, I will spot measure all the pressure points Redsnake suggested and compile a report and send it to ARISA and Nidec.

Thank you everyone for your help.

• https://files.engineering.com/getfile.aspx?folder=8e6bd370-bdac-4684-9c76-f

His setting is 50%, 40% was suggested in the Siemens manual for hydraulic pumps.
Maybe setting it up to 55%-60%
Maybe even shortening the ramptime a bit.
And the setting for Motor current was 25A should only be ca. 18 A

Another funny thing is that according to ABB there is no values for 60hz 415 Volt
https://www.electricautomationnetwork.com/PDF/PIM/...
Only for 460 volt.

At 60Hz 460 volt the motor can deliver 59.30 Nm I am guessing it is the same at 410 Volt.
The pump needs around 63 Nm to be able to deliver 130 bar.
At 50 Hz the motor will give 71.70 Nm which is enough.
Still think the max pressure will have to come down for this to work.

NAFO Sergeant Anna Gr 69th Sniffing Brigade

Quote (Roy)

I do not know much about hydraulics, I am a Controls Systems Engineer, and I do not know why they are not listening to me.

If you refer to ARISA it's because they are Spaniards.

NAFO Sergeant Anna Gr 69th Sniffing Brigade

Quote (Roy)

I agree with Redsnake. I am going to take some pressure readings at the points where he she suggested and present these findings to ARISA and Nidec.

NAFO Sergeant Anna Gr 69th Sniffing Brigade

The first step in trouble shooting a motor is to check the voltage.
When the frequency is changed, the voltage must be changed in the same ratio.
This is the first step.
Get the proper voltage to the machine before worrying about anything else.
The motor is rated at 460 Volts at 60 Hz.
460 Volts is a standard North American motor voltage.
460 Volt rated motors are normally fed from 480 Volt systems.
This is to allow line drop in the motor feeder conductors.

Quote (OP)

I agree with all of you, in other places in the factory, our bus voltage is 480. We are using a special transformer on this Servo press for some reason.

It seems to be a no-brainer to get rid of the transformer and feed 480 Volts to a 460 Volt motor like the rest of the continent does.
Once you have the proper voltage to the motor, we can deal with any other problems.
BUT:
It may be wise to investigate the other components to determine their suitability for operation at multiples of 120 Volts, 60 Hz.
Hopefully the components will be dual rated for 50/60Hz.
Particularly check the drivers for the servo motors.

Quote (OP)

At 60Hz 460 volt the motor can deliver 59.30 Nm I am guessing it is the same at 410 Volt.

Bad guess.
Voltage below proper voltage = magnetizing current and field strength below proper field strength = peak torque and continuous torque below proper torque.

When you check components:
Any coils, relays, solenoids, induction motors etc; should have the voltage raised in proportion to the rise in frequency.
Any rectifying components should probably be fed with 110 Volts regardless of frequency.
If the servo drives rectify the input voltage and then invert the DC back to AC, they should be fed the same voltage (410 Volts) regardless of the frequency.
The drive will match the output voltage to the output frequency. (Subject to correction by the servo experts here.)

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

Quote:

Bad guess.
Voltage below proper voltage = magnetizing current and field strength below proper field strength = peak torque and continuous torque below proper torque.

So why is the torque the same for all 50Hz applications on this motor?

NAFO Sergeant Anna Gr 69th Sniffing Brigade

What if I run a separate feed just for this motor? A 480-volt feed to the top of the motor starter that feeds the soft starter. "Would the difference of 20 VAC be a problem?" It is not Delta, so there is no wild leg.

Of course, after I first verify the pressure readings and if the manufacture agrees, then change the settings from 130 bar to 110 bar.
By the way, it is not a servo motor.

"So why is the torque the same for all 50Hz applications on this motor?"

Because Power ∝ Speed x Torque. Since the power and speed (or Hz) remain the same, torque remains the same. That table merely shows how the motor can be configured for different supply voltages for the same speed (or Hz) and KW.

OP, since you already have 480 V, 60 Hz, run a 480 V supply to your soft starter bypassing the special transformer and see what happens.

Muthu
www.edison.co.in

"What if I run a separate feed just for this motor? A 480-volt feed to the top of the motor starter that feeds the soft starter."

There you go. SS can take 480 V input.

Muthu
www.edison.co.in

Quote (Roy Costa)

What if I run a separate feed just for this motor? A 480-volt feed to the top of the motor starter that feeds the soft starter.

Great idea Roy.
That earns you a star.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

Quote (Red)

So why is the torque the same for all 50Hz applications on this motor?

First, I didn't write the nameplate.
Second, I said peak torque and you are asking about rated torque.
Third, The available torque is what the manufacturer says it is.
And a couple of more questions:
First, Why does the rated current change when the voltage changes? If the winding will safely carry 20.7 Amps at 400 Volts whay will it not carry 20.7 Amps at 415 Volts?
Answer: It will safely carry 20.7 Amps at 415 Volts but then it will also develop more than 11.00 kW.
Second: When a 50 Hz motor is used on the proper voltage 60 Hz, it develops 20% more HP. Why is this not shown on the nameplate?
Answer:11.00 kW is more important to the nameplate writer than reality.
Notice that the rated torque drops from 71.7 Nm to 59.3 Nm at 60 Hz.
Does that mean that the motor may not carry the load on 60 Hz.
No, that nameplate is fantasy.
The reality is that the motor will develop 71.7 Nm when running on 480 Volts, 60 Hertz.
The motor will safely draw 20.7 Amps when the load demands 71.7 Nm.
That is the reality,despite the fantasy of the name plate.
(This story is real. Only the name (plates) have been changed to protect the guilty.)* paraphrased from the introduction to the an old radio series. Possibly Dragnet?
Remember; The peak torque may be 200% to 250% of rated torque. The nameplate writer has a lot of headroom to fiddle with the numbers for the rated torque.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

I came in this morning and the operator could not run the press becuase the lube system kept getting overloads trips on the soft starter. We reset the soft starter and I asked the operator to trip this function called overload that would dump the back pressure. After doing this, the press was able to come up normally without any overload trips. It is obvious that the higher rpm and the 130 bar set point is causing the back pressure. I am preparing a report to send to the manufacture and ask them to come onsite and make the adjustments to account for the back pressure. I am also going to suggest running a seperat 480 VAC feed to the top of the motor starter that feeds the soft starter.

Thanks everyone for your suggestions.

Well this overload system I didn't see that it was connected to the same pump as the lubrication.
Looking at the hydraulic drawings I can't see a good reason why the soft starter doesn't not trip if you turn of the overload system, unless you have to little oil in the system all together and the cylinders re drained back to tank when you turn it off, but then you should have other fault messages.
The 1750 psi (120bar) the operator says he needs that is shown here (green)



does not come from the 11kW pump but is produced by the maximator pump here (blue)..



Now I am guessing since I do not have the PLC code or the electrical drawings, my guess is that when you turn of the overload till valve is closed meaning you do provide oil to the overload system, whether or not any oil is drained out of it and back to the tank I don't know?



It still doesn't explain your problem with the tripping of the soft starter and why it doesn't with the overload system off.

At first startup and if the overload cylinders are empty it will ofcourse take a bit longer to fill them up and then oil needs to be shared with the lubrication distributors and it will take a bit longer to get a signal back from all of them that they are functioning and ready.
But this in itself should not make the soft starter tripp.

NAFO Sergeant Anna Gr 69th Sniffing Brigade

RedSnake,

I have attached a picture of the actual after reseting by the OL switch, that in turn dumpted the back pressure, then the overload on the soft starter would not trip. They were able to bring the press up after that.

• https://files.engineering.com/getfile.aspx?folder=bb6ad835-6541-424e-b7d1-3

Redsnake - Great tips. I have learnt something about hydraulic diagram.

Muthu
www.edison.co.in

A combination of low voltage and starting against back pressure.
That is a recipe for overload trips.
An analogy may be a domestic refrigerator that will not start against back pressure but will trip the thermal protection repeatedly until the back pressure bleeds off.
An added line of code to dump accumulator pressure before starting may be part of the solution.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

I agree, the manufacture disagrees and will be sending someone here tomarrow.

Good luck.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

Hmm not sure I actually understand what you mean by "reseting by the OL switch" is the OL switch this one?



From the general condition chain you need the following (Of Course without PLc code or El circuit drawings I am "guessing")



Overload switch In ON position.
The cam/ram in Top Dead Center (TDC)
Reply from all lubrication distributors that they have received oil usually done with induktiv sensors felling the main piston going up from the oil pressure.


The ram needs to be unlocked.

Then when all this is okey there might be two options..
Either it is the PLC that sets the oil valve =12-YH5 when the above the conditions are met.
Or the operator are supposed to push the Reset button seems less lightly though..
After this point the "Oil Pressure OK" value should show ca 1335 psi (92bar)



And keep on increasing up to the value set to say "Oil Pressure OK" 2147 psi (148 bar) or whatever is set in the PLC,
But this increase from 92 bar to > 148 bar is done by the Maximator and it needs air pressure to do it.
According to drawing 3.68 bar which seems correct if you truly have that.





Hmmmmmmmm... I think I see why this is happening......



In this picture the valves have emptied the overload cylinders.
So when you start the pump again they need to be filed up, as long as the the flow have somewhere to go the pressure increase will next to nothing much lower than 92 bar at pos 60.3 if it takes longer to fill up the cylinders and start pressure than it takes to start the pump the soft starter wont tripp.



Another way of solving this at least until a permanent solution for the root cause is fixed would be to set this valve YH2 for the ram balancing cylinder to 1 for 10 seconds when the pump is started the the back pressure would only be 35 bar.



It might not be right but I think it would work.


NAFO Sergeant Anna Gr 69th Sniffing Brigade

RedSnake,

The press manufacture still thinks the problem is with the softstarter. They are sending a support engineer to install a new motor starter and a soft starter. Very frustrating.
They will see for themselves this is useless. They need to do those things that you and a few others suggested. Thinking that changing those starters will fix it is like
thinking you can change the music by replacing the speaker. They will find out.

And yes, the over load switch is the one you showed the picture of. After setting it to the off position for 20 seconds and then back to the on position, they was able to run the pumps and group lubrication circuits without tripping any overloads, hense, the OL switch dumpted the back pressure.

Okey
Let us know how things work out.

NAFO Sergeant Anna Gr 69th Sniffing Brigade

Will do, thanks again.

The service engineer from Nidec came in yesterday and was set on just replacing the motor starter and the soft starter. He was present to witness the soft starter overloading at start up and after using the hydraulic OL button to release the back pressure and reseting the soft starter OL, he is convienced that changing the starters will not fix the problem. He, did agree with me that if we supply 480 VAC to that circuit to bring the motor to what the motor name plate states, the same problem will be there until we change the hydraulic settings after the pump. If we change the settings to 110 bar, he says that we would have to go to ever place where there is a lubrication point and make sure they are getting the designed lubrication and make adjustments or replace parts as needed. Nidec is reluctant to do that.

The other option would be to add a NO BIT in the place that would trigger a TON delay for 500ms that would come on when the lube pump button is pressed that would trigger the hydraulic OL circuit just as you would do from the PCM panel. That would dump the back pressure just before the lube pump turns on.

By the way, the back pressure reguator is set to 121 bar, not 130 bar according to ARISA's drawings.

I do not think you will have a problem with the lubrication if you turn the pressure down until you get around 18 Amps on the motor.



The function that requires most pressure is the overload system and that is at most 92 bar so you can't go lower than that.
Or actually you could if needed, the maximator would still build the same pressure but it would just take longer.
But I don't think you need to go that low.

The pump have a flow of 48 liter/min at 60Hz
All the lubrication distributors together needs 2.166 liter/min.
300 cc/min *6 + 240cc/min + 58cc/min + 68cc/min.
So you will still have more than 45 liters/minutes for all other functions and that is still 5 liters more than the total if you had, had a 50Hz system.

You still need to measure all the lubrication flows as he says to confirm.
The only pressure required for the lubrication is to push the oil to the highest point and overcome the distributors internal backpressure, how much that is I don't know.
But the flow isn't a problem here.


NAFO Sergeant Anna Gr 69th Sniffing Brigade

Or just remove the soft starter and start this pump DOL?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

Hmm well I am no big fan of soft starters (I am an old fashion girl ).
We do have 11 kW hydraulic pump that we start just with a contactor, no problem.
But that one only have a back pressure at 45 bar so it never starts with full load, maxload is 200 bar.

Even starting the pump with just a contactor, you would still run the motor above the documented amps from the manufacturer.
So you would still just have solved half the problem.

NAFO Sergeant Anna Gr 69th Sniffing Brigade

I agree with both RedSnake and LittleInch. I will suggest removing the soft starter.

It's not the best thing for sure, but don't most motor starters and motors accept a short term high starting current?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

Yes they do.
But this is a S1 duty motor so it should not be started that often then it will go to warm.

But just starting it on the contactor isn't such a quickfix as it sounds apart from it still will have to work over it's ratings.
You need to redraw the electrical drawings and go through the PLC code and replace or fix all the places where the inputs from the soft starter is used and handle whatever turns up, most probably the HMI pictures needs to be remade and the outputs used to control the soft starter also needs to be reconnected to get the same functionality and all the hardwired stuff in the cabinet must be made for the same functionality.
It is quite a lot of work actually.

And since the motor starter also have been tripping I don't think this is the way to go.

Instead of taking it away, you could just put it at 100 % voltage, max current and 0 sek start time or something, it should be the same, don't think it will work though and I am not recommending it, the motor breaker will just tripp instead even though it is set to 2 amps more than recommended.

I do not think there is any way out of this more than reducing the torque/backpressure so the motor can work at it's ratings.

NAFO Sergeant Anna Gr 69th Sniffing Brigade

Quote (LittleInch)

but don't most motor starters and motors accept a short term high starting current?

Yes.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

Is the lube oil pump centrifugal or displacement?

It is a gear pump.

NAFO Sergeant Anna Gr 69th Sniffing Brigade

Here is what I have today. Please read the attachment.

• https://files.engineering.com/getfile.aspx?folder=e0ee5efa-e977-487d-a58e-8

I don't understand, maybe I missed something.
Why the insistence on starting against back pressure?
It seems to be quite easy to automatically dump back pressure before starting.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

Well this dumping of the back pressure via the overload cylinders, even if it can be done it's time consuming and takes energi to have to fill them up again every time.
They should really never be dumped unless the ram can't turn in bottom dead center.
They are there to protect the rods and mechanic of the press if there are double sheets or the wrong die is inserted.

It would be much more effective to allow the YH2 to be set while the motor is starting then the back pressure would only be 35 bar and the balancing cylinder only takes 68cc/min so 10 seconds more or less wouldn't be a problem.

NAFO Sergeant Anna Gr 69th Sniffing Brigade

Excellent job by RedSnake at diagnosing the problem.

Fundamentally, here is a problem that a lot of people seem to have.

Quote:

We keep getting overload trips on the soft starter and at times, we get overloads on the GVME22 motor starter. I thought the soft starter was going bad

There's a device designed to detect motor overloads and shut the motor down when it does detect one. Or in this case, two devices designed to detect motor overloads.

When it does its job the first thing that many people think is "the overload detector must be broken."

Why? Shouldn't the first thing that crosses your mind be "my motor is overloaded!"

I can't help thinking that 480 Volts and DOL would start the motor even against back pressure.
And I can't help but think that starting against back pressure needs lots of torque, which the soft starter may not provide initially.
I have to wonder if the pump does not start to turn until the soft starter has ramped up enough to provide enough torque.
I understand soft starters to start high inertial loads, which a hydraulic pump is not.
But I understand that I don't get to say.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

In this application I'd think about changing the soft starter to a VFD, set to run the motor at 50 Hz and whatever voltage that it's happy with.

Most VFDs have a programmable start ramp as well.

Ramping up against a stall doesn't seem like a great idea to me, but I'm a mechanical guy, so what do I know.

The whole hydraulic system setup is strange to me.
As you say waross starting a hydraulic pump with max load isn't common, even if it is doable, it is usually not how it is done.

Since the the torque curve is quite linear from 1000 rpm and upwards maybe the settings should be more like for an extruder that has the same load from start to finnish.

Then the settings on the soft starter should be something like this.

Trip class: 20 (maybe 15 will be enough)
Motor current: 18.8A Ie should be set to nameplate according to Sirius manuale.
Current limiting: Max (Will allow 18.8 x 6 = 112,8 amps at start if the amp goes higher the softstart will lower the Voltages out to the motor to keep the current below this value.
Two things here you might want to measure the max peak current when starting the motor this will give you an idea how to set the Current limit.
Or measure the voltage during start if it goes down somewhere during startup the current limit might be to low.
Ramp up time: ?? Seconds
This time might be measured even if the pressure is't linear with rpm the time should not be shorter than it takes to build pressure up to 105 bars which was the pressure at 18,86 amps.
It should never be longer the 15s according to ABBs general rules for a 4-pol motor size 160.
Starting voltage: 70%
Ramp down time: 0 Seconds

And also according to the Sirius manual you might need to give the softstarter a bit more space, don't really think this will solve the problem all together but it would be nicer for the starter.



With this soft starter you can't start the motor more than 5 times in an hour, when you where testing this new settings could it be that you didn't wait euomough between the starts to allow the soft starter and motor to cool down and that might have made it tripp?

Back to the hydraulics.

This pump, to call it a lubrication pump is a bit misleading even if it have that funktion too but only for lubrication you could have done with something much smaller.

In this system you have 4 pressure reducers.
1. pos 30 (130 bar) now 105 bar it is there only to prevent the motor or pump, in this case the motor to overheat or draw to much current, it is like a hydraulic safety valve, isch..
2. pos 60.1 (60 bar) for the table looking it is only at 60 bar when you want to drive the table out when doing die change.
3. pos 60.2 (35 bar) for the lubrication of the balancing cylinder.
The reason for reducing pressure here is not to press the lubrication oil pass the cylinder gasket that separates the piston and piston rod from the lubrication side and into the pneumatic cylinder filling it up with oil.
4. pos 60.3 (92 bar) overload cylinder system, this system only needs to be re-pressurized after a overload tripp when the cylinders are empty, as I said before the maximator will pump up the pressure higher depending on the settings in the PLC, if this pressure on this pressure reducer would be lower the same effect can be reached by increasing the air pressure to the maximator or with the same airpressuree it will just take longer.

For the lubrication that does not have pressure reducers as I said the amount needed in total is 2.166 liter/min.
That is why I say it's a bit misleading to call this a lubrication pump when it gives 48 liter/min.

I have a lubrication pump in our 800 ton hydraulic press.
It's really tiny and cute only 0,18 kW max 0,12 l/m but we only use 0,003 l/M the back pressure is set to 35 bar but it only works between 12-25 bar.
But as I said the pressure only need to be so high that it can push the oil to the highest point which in this case is about 8-10 meters.

And since the reducer for the balancing cylinder is set to 35 bar without having seen the press my assumption is that it is lubricated at the top which is most likely the highest point of the press.
Which means that 35 bars is enough to get the oil to all distributors.

So what does all of this mean.

Lets say the pump is running and you want to change the die.
To do that you need to drive the ram down to unlock it and then the overoad system needs to be ok.
If it is not then it needs to build the right pressure and you would have 92 bars in the lubrication system after that is done the ram can go down and to make one or two strokes with the ram the amount of oil that is already there on the balancing cylinder from the lubrication would be enough even if it doesn't start.
Then the die cart cylinders are raised and the pressure will be 60 bar until you have driven the table out and then back in again.
Ram down lock the die and the back up again.

So what would the pressure look like.

105->92->105-> (35 or 105)-> 60-> 105.

At production the same thing overload okey to drive ram down, lubrication okey (in my opinion) 35 bars would be enough.

105 -> 92 (if needed)-> 35 bar (in my opinion) if the 2HY isn't set all the time during production the pressure will be 105 bar and will only go down to 35 bar when lubrication is needed for the balancing cylinder.
But I can't see why it shouldn't be lubricated constantly during production.
Ours are.

I still think you should look at the the conditions for setting 2HY.
There is never a need for the system to work at 105 bar (130 bar) the max is 92 bar when the overload system needs to increase the pressure which should be "never" unless it has tripped.

So in my opinion the back pressure should be 35 bar as long as a die change is not going on or the overload has tripped.

NAFO Sergeant Anna Gr 69th Sniffing Brigade

Early in my career I worked in a number of lumber mills.
All had hydraulic systems of around 10 HP to 15 HP.
All started DOL against back pressure.
Given that the manufacturer has apparently not encountered this issue with 50 Hz applications:
As I have said several times;
"The first step, the very first step, in a 50 Hz to 60 Hz conversion is to supply the correct voltage as per the V/Hz ratio."
With 410 Volts vs 480 Volts, the starting torque is already down to 73%.
The soft starter is probably making the starting torque even less.
"The first step.....
I appreciate your analysis of the operation of the press, Anna, but when the motor is showing the symptoms of low voltage and the voltage is low...???

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

One does not exclude the other.
I have no opinion about changing to 480 volts.
Simply because I have no experience of that since I live in 50Hz 230 /400 volt country and all our motors are optimized for that.

I don't agree with changing it to direct online start I guess that is what you mean bu DOL?
Simply because it is to much work, and starting at full load would wear unnecessarily on the mechanics, waste energy and it is not necessary.

The reason it is not necessary is that while starting the motor neither the lubrication or the overload system or any other function this pump supplies is needed in the press.
So starting it against 35 bar back pressure is okay and will not damage the press.
After startup, before running production the lubrication need to be ok (35 bar should do it).
And after unlocking the ram the overload should be ok.
But if that need to be re-pressurized I would say there is something wrong with it, internal leakages or something.
But even if pressure there needs to be 92 bar for re-pressurized after start up it should not be a problem after the motor have started.

After that during ordinary production 35 bar should be enough for the lubrication.

The pressure reducer PRDM2BB21SVG15 even if fully open it can only drain 20 liters/ minutes so there would still be 28 liters per minutes left.
At 35 bar their with be more left.



And at die change 60 bars will be needed but there is no need for lubrication.

In theory this system motor(pump) should never run at 105 bars only max 92 bars at short intervals.

NAFO Sergeant Anna Gr 69th Sniffing Brigade

Quote (Anna)

Simply because I have no experience of that since I live in 50Hz 230 /400 volt country and all our motors are optimized for that.

"I have no experience of that"
I have experience with that. Both 50 Hz to 60 Hz and 60 Hz to 50 Hz.

"I live in 50Hz 230 /400 volt country"
That's a V/Hz ratio of 8:1
At 60 Hz that is 480 Volts.
What would be your first reaction if you had a complaint of a 50Hz 230 /400 motor not starting properly and found that it was supplied with only 333 Volts?
That is analogous to running the 50 Hz motor on 410 Volts, 60 Hz.
Would you not strongly suggest applying the proper voltage before doing any other trouble shooting?
First step....
Volts per Hertz....
Been there, done that..

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

At 410V, motor torque is reduced with 35-40% below nominal... so how can motor overcome load torque if this is above what motor can develop?
Motor starter is a controlled thyristors device, that reduce applied voltage to reduce initial start-up current; but voltage is already too low and motor can't accelerate (because torque is not enough) and current increase as starter increase applied voltage in specified ramp time; so current increase above max set current and trip is a normal event to protect motor...

Switch to 480V and all issue will be solved.
Or remove motor starter... but add a motor relay.

Quote (waross)

What would be your first reaction if you had a complaint of a 50Hz 230 /400 motor not starting properly and found that it was supplied with only 333 Volts?

I would have to call the power company, the largest in Sweden and ask what the h.ll they were up too.
That has never happened, the opposite have happened though but that is another story.

Quote (waross)

Would you not strongly suggest applying the proper voltage before doing any other troubles hooting?

I think you misunderstood me, maybe it is my Swedish humor?

I didn't strongly suggest applying the proper voltage first, because you already did.
So I didn't feel that I needed to confirm your statement, since I know you know these things better.
I have never needed to deal with this problem or even think about it and I will never have to.
So I just decided not to comment on it at all.
And I didn't disapprove or approve or agree or disagree with your suggestion to run the motor on 480 VAC.
Neither did I say do this first and then this second or do just this and not that.
When it came too starting the pump with 35 bar backpressure.

The only thing I disagreed with was changing the SS to a contactor and the reason for it is that, if this press had been sold in EU then making this change would render the manufacturer to make a new CE declaration.
It would be almost impossible to get the manufacturer to do that.
Doing it yourself, would mean, apart from all the work, that you would take on all the responsibility for the guarantee and safety for the press.

I have no clue what the rules are for this in North America or even in Michigan, but since I don't I rather say don't do it, and be safe than sorry.

And for trouble shooting before or after.
I don't see it as troubleshooting, I have been involved in buying 9 presses and several other machines at my company.
And mostly my job has been to confirm that we get what we have bought and is paying for in terms of dokumentation and function.
But doing this on every single thing/item isn't doable it would take forever.
So my mentor said look at every tenth ting and if you find many faults or some mayor ones you need to start looking at everything else too.
But to be able to do that you need to know the functionality of the machine so it more about that than troubleshooting.
You are going to have to live with this machine for many years so it isn't a waste doing it, sooner or later you need to anyway.

Maybe this was my mistake I should have asked Roy about this.
He said the press was bought and it wasn't made for the US market.
But he never said..
When it was installed?
And by who?
And who commissioned the machine?
And if this problem was there during commissioning?
Or if it turned up later?

My assumption was that if this would have happened during commissioning, at least I would have told the manufacturer or commissioner that you need to fix this otherwise you won't go home and you won't get payed.
So when Roy said that we got this problem I assumed it was something that had turned up later.

NAFO Sergeant Anna Gr 69th Sniffing Brigade

Quote:

I would have to call the power company, the largest in Sweden and ask what the h.ll they were up too.

In this case the power company may answer;
"Your motor is rated for 460 Volts.
It is universal practice in North America to supply 480 Volts to 460 Volt rated motors.
Our smart meter shows that we are supplying a stable 480 Volts to your plant.
You, on the other hand, have instead opted to install a transformer supplying 410 Volts to the motor.
As there is nothing wrong with our 480 Volt service, you will be billed for a service call."

Am I the only one here who has ever done a frequency conversion?
Am I the only one here who is familiar with the symptoms of too low voltage? (Often due to line drop on too long branch circuit conductors.)

With 480 Volts supplied to the motor, the torque will increase by a factor of about 137%.
With 37% more torque (the same torque as would be produced by 410 Volts 50 Hz.) the motor will probably start with the original 50 Hz based settings on the soft starter.

Investigate Volts-per-Hertz for motors, transformers and other inductive devices.




--------------------
Ohm's law
Not just a good idea;
It's the LAW!

Now everything becomes very hypothetically.
In Europe and Sweden we have 400VAC 50Hz so any motor I would put in would be rated 400/690V, 50hz, IE3 or if it is a small one 230/400V 50Hz IE3 that is EU standard.
And no at least I have never encountered the symptoms of too low voltage.
We have double incoming feeds from the water power station that is located less than 11 km from the factory.
So either there is power and it is correct or there is not.
Would say that at least here in Sweden it will never happen.
So for that reason I have never had to do a frequency conversion.

And why who ever it was that installed or commissioned this press in the States chose to put it on a 410 volts transformer only Roy may know.

This motor is a EU standard motor 400/690V, 50hz but the press can not have been intended for the EU market to begin with, because the motor was manufactured in 2019 and it has been forbidden to use IE2 motors here since 2017.

Where the settings on the soft starter comes from is unclear they don't correlate with any recommended settings for this motor regardless of the voltage supplied.

I will make a guess here and say that this press might have been intended for Russia reason being most drawings are made in Aug 2021 probably start of manufacturing but the hydraulic drawings were made in May 2022 either they were remade or finished but after that the deal for some reason fell through.

NAFO Sergeant Anna Gr 69th Sniffing Brigade

Show the motor some love. Give it some nourishing juice.

Muthu
www.edison.co.in

Motors develop torque that is proportional to the square of the applied voltage. This means that if 410 is applied (and rated is 460), then the motor only produces (410/460)^2 * whatever the rated torque is for that speed point. In effect, the reduced voltage applied results in THE ENTIRE STARTING CURVE being 79% of the "expected" value, until the voltage is brought up to the correct operating value (i.e. 460 V).

The system has backpressure - it is how hydraulic systems are consistently operated (for the reasons given by RedSnake!). How much backpressure is present can be adjusted through judicious application of valving and oil viscosity. If the motor does not develop enough torque to overcome the load (i.e. the back pressure), it will continue to attempt to do so by ratcheting up the current draw from the starter. Eventually, either the backpressure is overcome and things go on about their normal lives, or the protection elements kick in and stop the process (in this case either on instantaneous overcurrent or on short time overcurrent - which is really current vs time).

The starter(s) are doing their job correctly, and the motor is trying to do its job correctly too. The system parameters (backpressure, current limits, "start time", etc.) are wrong for what the motor can actually accomplish - or the protection is set too close to running values to allow the start sequence.

The big question is that when supplying 410 to the Schneider device, what voltage(s) appear at the terminals of the Siemens device and the motor itself? At the beginning of this discussion, I assumed that 410 appeared at the motor terminals as well, but I could be wrong. If it's lower, the developed torque is also lower and the motor (driving the pump) less likely to overcome the existing backpressure.

Converting energy to motion for more than half a century

I want to thank everyone for your input. So far, the Soft Starter had not tripped since I adjusted the back pressure and adjusted the setting on the Soft Starter. I explained what I did in my last post in the attachment. I have learned a lot from all of your input.

Quote (Anna)

And no at least I have never encountered the symptoms of too low voltage.
.....
.....
Would say that at least here in Sweden it will never happen.
So for that reason I have never had to do a frequency conversion.

Anna, I am usually impressed by both your technical knowledge and your practical knowledge.
But in this case, you have admitted that you have no knowledge or experience of the issue.
I will be glad to walk you through the theory, but as a mentor and not as an antagonist.
Should your plant ever have occasion to purchase 60 Hz equipment, you will be able to competently and confidently install and operate the equipment on your 50 Hz supply.

Low voltage hint: Look at this table from the Cowern papers to see the effect of low voltage on starting torque:


The motor is being fed with 410 Volts at 60 Hz.
It should be fed with 480 Volts at 60 Hz.
410 Volts is 85% of 480 Volts.
The torque may be expected to be .85² of rated torque or 73% of rated torque.
The starting torque of a design "B" motor (the most common design) is about 150% of rated torque.
73% of that is 109% of rated torque.
The pull in torque may be as low as 120% of rated torque.
At the reduced voltage the pull in torque may be expected to be about 88% of rated torque.
A positive displacement pump starting against back pressure is basically a constant torque load.
That marginal 109% torque will be further reduced by the soft starter.
If the motor even starts to turn it may be unable to get past pull-up RPM before the soft starter nears the end of the start-up ramp.
By that time the I²T of the locked rotor will be at or close to the trip setting.

Quote (Cowern Papers)

When the ratio of volts to hertz stays constant, the
motor can be operated at the reduced frequency and
reduced voltage.

The corollary is true:
When the ratio of volts to hertz stays constant, the
motor can be operated at the increased frequency and
increased voltage.
Cowern Papers

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

Still periodically tripping the soft starter. Nidec & Arisa are not working on it, onsite and remotely. I believe we need to do one of 2 things, use a VFD or bring in 480 VAC and tune the soft starter or replace it with another one with a higher volt/amp capacity. I do not believe they will be able to tune this one.

The basics of frequency conversion: Keep the Volts per Hertz ratio the same.
You have increased the frequency in the ratio of 60Hz:50Hz or 6/5
You should increase the voltage in the same ratio.
6/5 x 400 Volts = 480 Volts.
With 480 Volts you will have the same torque as produced at 400 Volts, 50 Hertz.
By the way, the HP also changes with the change in frequency and voltage.
With the same V/Hz ratio (480 Volts at 60 Hz) the motor will produce the same torque but turn 6/5 times faster.
When you supply the motor with 480 Volts, you probably won't have to worry about hydraulic circuits nor pressure settings.
I would set the soft starter to as close to DOL starting as possible.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

Thanks Waross,

I will pass this on.

I am a bit curious, has this been a problem from the start the commissioning?
Or did it turn up later?
And who did the commissioning?
And who decided it was to be put on 410 Volt transformator?
Does it tripp at start?
Or after running a while?
How often do you stop and start that motor?
As I said before you can only start it 5 time an hour you need to wait at least 12 minutes so the starter can cool down, between starts.

That soft starter should be able to handle that motor if you put it on 480 Volts with the right settings, so I don't think you need to change it.
And if you can change the program so it starts on 35 bar it should definitely not be any problem with the SS on start up.

NAFO Sergeant Anna Gr 69th Sniffing Brigade

I once converted an entire gravel processing plant from 50 Hz to 60 Hz.
The plant was imported from Europe.
It consisted of shaker screens, washing equipment and vibrators.
One vibrator was overloading slightly at the higher speed, The weights were adjustable and an adjustment of the weights fixed the problem.
As I have said, the first step was to calculate the V/Hz ratio of the motors and then set our generator voltage to the correct voltage.
Your motor will run faster, there is nothing short of the expense of a VFD that you can do about that, but that should not be a problem, seeing as I understand that the machine works OK if you can get the pump started without tripping the overloads.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

Quote (waross)

Your motor will run faster, there is nothing short of the expense of a VFD that you can do about that,

Half true since the motors only function is to supply the hydraulic system via the pump with 40 liters/min.
By reducing the pressure on the pressure reducer 31 (130bar) you will be able to drain of the excess 8 liters that the higher rpm on the motor gives you.
So there is no need to use a VFD to make the motor go slower.

NAFO Sergeant Anna Gr 69th Sniffing Brigade

RedSnake,

We have been having this problem for months. And, there have been all kinds of problems with this press. The safety breaks on top of the press keep failing, and they have been replaced several times, and the only way to reset them is to turn off the lube systems to let them drain, (mechanical reset). All kinds of seals had to be replaced, (bolsters, etc.). Support is difficult, all the drawings are mostly in Spanish and I just got approved for the Siemens PLC software so I can use it to see the live code and look at what the permissives and interlocks are to troubleshoot. Spain is 6 hours ahead of us, so when we need support, we are out of luck if problems occur after their hours. And, even when we do have them, the there is a lot of misunderstanding because of the language difference. And, we had to depend on them remoting in, which at times causes profinet errors because of their connection.

I have all the drawings, however I got to dump them in google translator to read them, and, I had them print out the PLC code, however, it is all in spanish. It is one of the most complicated systems I have ever seen. The press cost $7 million dollars. It was designed to work in France on a 50 Hz system and they (we) have had nothing but problems with it. However, when it is running, it is very impressive. But, when it goes down, it is down.

Arisa & Nidec did the commissioning.

It only trips the OL and has all kinds of lube errors at the start up of the lube system. The motors shut off automatically after 1 hour if the press is not producing and we run 2 shifts, so we have to restart the motors after a die change, sometimes a roll change if there is problems and first thing in the morning.

In which way does the safety breaks cylinders break, is it the sealings?
What pressure do you have when you are driving the press in auto on the 31 (130bar) manometer?

NAFO Sergeant Anna Gr 69th Sniffing Brigade

Ditch the SS for a 480 V VFD. Run it at the desired pump speed. No starting hiccups including inrush current.

Muthu
www.edison.co.in