Functional Software description
DCS 500 Software Description 65
•
Protections
CONVERTER_PROTE
CTION function block
Network voltage
measurement
The measurement/calculation of network voltage is based on the
nominal voltage of the converter, nominal voltage of the supply and
the voltage measurement as follows:
U NET ACT
U SUPPLY
eg
measured
()
*()
()
..
*
%10504
10511
507
3276 500
400
4095 100====
400 V supply Note. DCS 500B converter module is exactly the same for 400V
and 500V supply. Voltage measurement scaling is constant 500V =
4095. U CONV V (10511) signal value must be 500 also for 400V
supply (software reads this value automatically from the SDCS-
PINxx board when C1, C2 or C3 modules are used).
Network under-
voltage
The nominal net voltage is defined in U SUPPLY (507). The upper
limit for network undervoltage is defined in % by parameter U NET
MIN1 (508). If the network voltage drops below this limit, the con-
trollers are blocked. An undervoltage trip is generated if network
voltage is not restored within the time defined by parameter PWR
DOWN TIME (510). Scaling 1 == 1 ms.
The lower limit for network undervoltage is defined in % by pa-
rameter U NET MIN2 (509). If the network voltage drops below this
limit, the drive is tripped immediately.
Network over-
voltage
The overvoltage limit is fixed to 130%. If this limit is exceeded, and
the situation continues for at least 10 seconds, an
OVERVOLTAGE-fault will occur. Armature overvoltage level is de-
fined in % of nominal voltage of motor by parameter
ARM OVERVOLT LEV (511).
Overcurrent There is a fixed overcurrent limit for the converter, and this value
can be read out from the signal
I TRIP A (10510) (scale 1 = 1A)
If there is a need to reduce this limit, it can be done with the pa-
rameter:
ARM OVERCURR LEV (512)
scale: 100 = nominal current of converter I CONV A (10509).
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