Inverter NP-Voltage deviation fault ABB ACS 1000
Inverter NP-Voltage deviation fault ABB ACS 1000
(OP)
Dear All,
What could be the cause of the Neutral point unbalance fault in the inverter while the motor is running at low speed?
For information this is the sequence of events
183.58.3 "NP Voltage "
183.72.1 "AMC: Fault Class 2 "
6.21.7 "INU Tripped "
6.21.19 "INU StopCmd "
9.9.12 "Unbalance NP "
183.72.11 "INT: MCB Trip Req "
6.21.11 "MCB TripCmd "
9.9.0 "TrippLoop "
183.72.0 "AMC: Fault Class 1 "
Thank you in advance
What could be the cause of the Neutral point unbalance fault in the inverter while the motor is running at low speed?
For information this is the sequence of events
183.58.3 "NP Voltage "
183.72.1 "AMC: Fault Class 2 "
6.21.7 "INU Tripped "
6.21.19 "INU StopCmd "
9.9.12 "Unbalance NP "
183.72.11 "INT: MCB Trip Req "
6.21.11 "MCB TripCmd "
9.9.0 "TrippLoop "
183.72.0 "AMC: Fault Class 1 "
Thank you in advance
RE: Inverter NP-Voltage deviation fault ABB ACS 1000
I’ll see your silver lining and raise you two black clouds. - Protection Operations
RE: Inverter NP-Voltage deviation fault ABB ACS 1000
RE: Inverter NP-Voltage deviation fault ABB ACS 1000
This is a 3-level inverter and balance of neutral point is an issue... that depend of modulation index, power factor, modulation strategy.
Check settings about modulation / switching frequency and check power factor also.
Low motor speed is with low torque also? In this case power factor is very low.
RE: Inverter NP-Voltage deviation fault ABB ACS 1000
RE: Inverter NP-Voltage deviation fault ABB ACS 1000
ABB has been promoting such kind of drives using reverse conducting IGCTs more than 10 years ago, but I'm not aware that such drives play a significant role on the market nowadays.
Potential reasons for such an unbalance can be manifold, just some examples here:
- offset of output current sensors
- leakage currents
- unequal propagation delay of drivers
- variation of swicthing delay of the power devices
- improper deadtime compensation
When designing such a drive such effects have to be considered and some balancing means habe to be implemented, either passive (resistors) or active (adaption of the modulation scheme. Motor data rarely have an impact
RE: Inverter NP-Voltage deviation fault ABB ACS 1000
RE: Inverter NP-Voltage deviation fault ABB ACS 1000
https://library.e.abb.com/public/223c97dd659f41bd9...
In general it is a good idea to do such an upgrade on large equipment after some years in the field (for the user as well as for the supplier), but this kind of service should provide the benefits which are used for marketing it.
I would be more pushy towards the supplier in your case. The problem is that for such case you are in a weaker position compared to a new installation where you can hold back significant amount of the total payment in case the equipment doesn't perform as specified.
RE: Inverter NP-Voltage deviation fault ABB ACS 1000
" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden
RE: Inverter NP-Voltage deviation fault ABB ACS 1000
Evidently , if you really need to run on such low speeds, it was found that in some cases it is helpful to enable the new NP control functionality, to get rid of nuisance NP voltage faults.
134.09 NP CURR FILT (T2) -> 0.1
134.36 NP LIMITER -> ENABLE
134.43 NP ISIGN TIME LEV -> 25us (T1)"
now they made it clear that the model is not accurate, i'm afraid that it could do some damage to the MOtor that is an expensive one!! what do you think ?
RE: Inverter NP-Voltage deviation fault ABB ACS 1000
From my point of view a good inverter control should not rely on on a detailed motor model going beyond nameplate data. My view on this is clear:
If the drive ran proper for 10 years prior to the upgrade, it should do so also afterwards. If not I'd expect the supplier to fix it when installing the upgrade.
RE: Inverter NP-Voltage deviation fault ABB ACS 1000
This upgrade seem to have problems at low speed ... and most probable have new digital control cards and seem have forgot or ignored zero sequence in NPC inverters that become a problem at low speed (low output frequency).
"Motor model" issue would have to affect motor control torque... not NP balance.
RE: Inverter NP-Voltage deviation fault ABB ACS 1000
Was this an actual aBB technician, or a 3rd party company contracted to ABB (as they do in some areas)?
" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden
RE: Inverter NP-Voltage deviation fault ABB ACS 1000
RE: Inverter NP-Voltage deviation fault ABB ACS 1000
I think autotune failed because an issue (software) in new controll cards... but motor age may be a "good guilty".
RE: Inverter NP-Voltage deviation fault ABB ACS 1000
" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden
RE: Inverter NP-Voltage deviation fault ABB ACS 1000
It seems software issue