7.2.1.2
Electrical motor protection by overvoltage/undervoltage monitoring
PumpDrive monitors the mains voltage. If it falls below 380 V -10 % or exceeds 480 V
+10 %, this results in tripping and an alert message is output. The alert must be
acknowledged before the drive can be restarted.
7.2.1.3
Dynamic overload protection by speed limitation
PumpDrive is equipped with current sensors that record and limit the motor current.
When a current that exceeds the nominal motor current IN (
3-3-2-4
) is measured, the
square of the overcurrent is totalled over time. If the total reaches an upper limit
value, PumpDrive responds by reducing the speed until the current consumption of
the connected motor reaches the nominal motor current again. PumpDrive can then
no longer reach the setpoint, but it maintains operation at a lower speed. The
dynamic overload protection function takes into account that motor heat-up varies
as the square of the motor current. Low overcurrent can flow for a relatively long
time, while a high overcurrent results in a rapid reduction in speed. The upper limit
value for i2t control, which depends on the nominal motor current IN, is (2 x IN)2 x 10
sec and is designed for standard motors. The dynamic overload protection function
can be made to respond more quickly by reducing the nominal motor current. When
a motor-mounted drive is delivered, this parameter is defaulted for the relevant
motor.
Table 69: Parameter for overload protection by speed limitation
Parameter Description
Possible settings
Factory setting
3-3-2-4
Nominal motor current 0, 1...999 (A)
Depending on the size
7.2.1.4
Current limitation
If the current limit value defined in the MotMod Curr Lim parameter
(3-6-1-4)
is
exceeded, PumpDrive reduces the speed until the limit value is no longer violated.
Unlike with dynamic overload protection, the speed is reduced without delay. When
a motor-mounted PumpDrive is delivered, this parameter is defaulted for the
relevant motor.
The current limit value refers to the maximum output current (
3-11-4-2
)
Table 70: Parameters for current limitation
Parameter Description
Possible settings
Access
Reference to
Factory setting
3-6-1-4
Motor mode current
limit
0..100 (%)
Customer
3-11-4-2
75 %
3-11-4-2
Maximum output
current
0 - 500 (A)
Factory
Depending on the
size
7.2.1.5
Tripping at phase failure and short circuit
Phase failure and short circuit result in direct tripping (without stop ramp). This
protective function does not need to be parameterised.
7.2.1.6
Cable integrity monitoring (live zero)
Live zero monitoring only works in automatic mode. If live zero detection is active,
the analog inputs are checked for cable integrity (broken wires) or sensor faults. A
prerequisite are signals with 4 - 20 mA or 2 - 10 V. If the lower voltage or current
value is defined as 0 V or 0 mA, cable integrity monitoring is not carried out for the
corresponding analog input. If the value falls below 4 mA or 2 V, a parameterisable
response is initiated after a parameterisable time delay.
Note: If the Live Zero Fnc (response to broken wire) parameter
(3-8-1-2)
is set to Stop,
the motor restarts automatically once the cause of the fault has been rectified. As
long as no signal is present, a warning, and not an alert, is displayed. A restart inhibit
can be set using Stop & Trip (
7 Commissioning/shutdown
PumpDrive
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