soft starter tripping issue

[Tameem1]

Dears

We have ABB ACS5000 as a soft started for compressor motor (7.5MW). Recently we are facing overcurrent issue in soft starter while starting the motor. We have done trouble shooting for the motor, cable transformer all of them working fine and no abnormality and we could not found solid reason for overcurrent trip. Sometimes soft starter is working fine and sometimes its tripping on overcurrent even with no load (uncoupled condition)while we are doing SOLO-run.

what is the possible cause for this problem

 

[jraef]

Well you may be using it just as a soft starter, but that is a VFD, specifically a 36 pulse Voltage Source Inverter using IGCTs on the output. Getting Over Current trips with the motor uncoupled sounds like an output thyristor problem, either with a thyristor itself or the firing circuit for it. Generally if it is intermittent I would suspect the firing circuit, as Thyristors tend to either work or fail consistently. A call to ABB is in order here and I would do it sooner than later. An intermittent firing circuit issue can easily turn into a very expensive thyristor issue at any moment.


"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington

 

[Watthour]

Is the drive directly firing the stator or is there some DU/DT or other filter in the circuit?

 

[panter]

My colleague had a problem with the similar regulator ACS 2000 and I know that there is good software and registry errors *I think name is black box * where it can be taken all the defects in real time. Unfortunately before good analysis he suspected thyristors and tried to change them randomly with spare which they had .
Finally, someone had to come from ABB and found that the initial failure was just high temperature in the cabinet .
Spare thyristor blocks which they bought from ABB as spare parts did not have latest firmwave and that they without their assistance and good price of their work totally useless .
A good idea is to immediately call someone from ABB .
What message do you get on the panel after fault .
Good luck

 

[Tameem1]

Yes, there is EMC filter (dv/dt limitation at output)

 

[Tameem1]

I called ABB Engineer, and he came to download the Black Box and he sent it to the Support line for further analysis, but they did not come with a real Rout Cause for the problem

 

[fiaz1404]

Try to start the motor in coupled condition with load