Help for critical issues
Help for critical issues
(OP)
Dear Experts !
I have got here an critical issue that messing me around day by day:
We have 6 tetrapak filling machine TBA/19 with GE-Fanuc 90-30 series, CPU 351.
The issues are : Machines will down randomly cause of following
- Grid line is not stable, sometimes power down in such time as flash, very fast, maybe just 1 or 2 second.
- We have test to transfer from grid line to generator. If from grid to generator, every thing is OK, but if from generator to grid, above symptom occur.
- If we just use CB to turn on and off and n machine, nothing happen, no error occured.
This kind of machine have a rung to check if power is loss for less than 4 second, it will recover its status, otherwise it will go back to the first step. The problem is it will take 4 hours to come from the first step to the production step.
The question here is:
- If tranfer from grid to generator, how much time does it take to reach regular voltage. Working voltage is 380 V 3 phase, total load is 450 KVA, generator is 600 KVA, transformer is 750 KVA, 50 HZ.
- How much voltage go down in starting period.
Thanks for your attention.
I have got here an critical issue that messing me around day by day:
We have 6 tetrapak filling machine TBA/19 with GE-Fanuc 90-30 series, CPU 351.
The issues are : Machines will down randomly cause of following
- Grid line is not stable, sometimes power down in such time as flash, very fast, maybe just 1 or 2 second.
- We have test to transfer from grid line to generator. If from grid to generator, every thing is OK, but if from generator to grid, above symptom occur.
- If we just use CB to turn on and off and n machine, nothing happen, no error occured.
This kind of machine have a rung to check if power is loss for less than 4 second, it will recover its status, otherwise it will go back to the first step. The problem is it will take 4 hours to come from the first step to the production step.
The question here is:
- If tranfer from grid to generator, how much time does it take to reach regular voltage. Working voltage is 380 V 3 phase, total load is 450 KVA, generator is 600 KVA, transformer is 750 KVA, 50 HZ.
- How much voltage go down in starting period.
Thanks for your attention.





RE: Help for critical issues
RE: Help for critical issues
If so, I would have a look at the transfer switch. If it is a closed transition switch, the generator and grid need to be in phase with each other, before the switch transitions.
RE: Help for critical issues
Or that the equipment the PLC's drive/run/control lose power and that the loss of power causes restart difficulties?
RE: Help for critical issues
1. Sorry i have made a typing mistake, problem occur when transfer from grid to generator.
2. We use ATS to transfer between grid and generator. I do not understand " in phase"". ?????
To danw2 :
Actually, if PLC know that power go down, it will recover all parameter before. But here PLC did not realize any lost of power, but some sensor send back the info. that parameters were not enough to continue,so it turn machine back to the starting point.
RE: Help for critical issues
It sounds like you need a UPS though, as danw2 suggested.
Depending upon the type of generator you have and how much voltage sag is allowed before it starts, it could be as much as 10 seconds before the generator output stabilizes and it picks up the load.
Although you may have a battery back-up to prevent program loss, if the program execution is interrupted the PLC isn't likely to know how long the power was off. The logic may be able to tell how long the machine power was off, but probably not if the PLC power is off too.
RE: Help for critical issues
RE: Help for critical issues
So it could be possible for the AC power to be cycled and not lose the DC power to the PLC.