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Fault tracing
3ADW000379R0501 DCS550 Manual e e
Fault tracing
Chapter overview
This chapter describes the protections and fault tracing of the drive.
Fault modes
Depending on the trip level of the fault, the drive reacts differently. The drive’s reaction to a fault with trip level
1 and 2 is fixed. See also paragraph Fault signals
of this manual. The reaction to a fault of level 3 and 4 can
be chosen by means of SpeedFbFltMode (30.36) respectively FaultStopMode (30.30).
Converter protection
Auxiliary undervoltage
If the auxiliary supply voltage fails while the drive is in RdyRun state (MSW bit 1), fault F501 AuxUnderVolt is
generated.
Armature overcurrent
The nominal value of the armature current is set with M1NomCur (99.02). The overcurrent level is set by
means of ArmOvrCurLev (30.09). Additionally the actual current is monitored against the overcurrent level of
the converter module. The converter’s actual overcurrent level can be read from ConvOvrCur (4.16).
Exceeding one of the two levels causes F502 ArmOverCur.
Converter overtemperature
The maximum temperature of the bridge can be read from MaxBridgeTemp (4.17) and is automatically set by
TypeCode (97.01) or manually set by S MaxBrdgTemp (97.04).
Exceeding this level causes F504 ConvOverTemp. The threshold for A104 ConvOverTemp is 5 °C below
the tripping level. The measured temperature can be read from BridgeTemp (1.24).
If the measured temperature drops below minus 10 °C, F504 ConvOverTemp is generated.
Auto-reclosing (mains undervoltage)
Auto-reclosing allows continuing drive operation immediately after a short mains undervoltage without any
additional functions in the overriding control system.
In order to keep the overriding control system and the drive control electronics running through short mains
undervoltage, an UPS is needed for the 115/230 V
AC
auxiliary voltages. Without the UPS all DI like e.g. E-
stop, start inhibition, acknowledge signals etc. would have false states and trip the drive although the system
itself could stay alive. In addition, the control circuits of the main contactor must be supplied during the mains
undervoltage.
Auto-reclosing defines whether the drive trips immediately with F512 MainsLowVolt or if the drive will
continue running after the mains voltage returns. To activate the auto-reclosing set PwrLossTrip (30.21) =
Delayed.
Short mains undervoltage
The supervision of mains undervoltage has two levels:
1. UNetMin1 (30.22) alarm, protection and trip level
2. UNetMin2 (30.23) trip level
If the mains voltage falls below UNetMin1 (30.22) but stays above UNetMin2 (30.23), the following actions
take place:
1. the firing angle is set to ArmAlphaMax (20.14),
2. single firing pulses are applied in order to extinguish the current as fast as possible,
3. the controllers are frozen,
4. the speed ramp output is updated from the measured speed and
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