Operating Instructions ACU
The output of the first PT1 element is connected to the input of the second PT1 element which
contains the thermal time constant of the motor. This output may be loaded at 100% permanently.
This corresponds to full thermal loading of the motor. Once 102% are reached, the inverter will shut
down and an error will be reported. Both outputs are linked to an adjustable Warning Threshold.
I²t, Single-Motor,
Err.Sw.-Off
The I²t load of the motor is monitored via the rated values from the
active data set. Once the fixed error threshold of 100%
Motor
(120%
Stator
) is exceeded, there will be an error shutdown “F0401” by the
active data set.
I2t,Multi-Motor
Op.,Warning
In each of the four data sets, the I²t load of the motors is monitored
based on the corresponding rated values. Once the set Warning Limit
I2t 615 is reached, a warning “A0200” will be triggered by the active
data set.
I2t,Single-Motor
Op.,Warning
The I²t load of the motor is monitored via the rated values from the
active data SE. Once the set Warning Limit I2t 615 is reached, a
warning “A0200” will be triggered by the active data set.
I²t,Multi-Motor
Op.,Warning and
Err.Sw.-Off
In each of the four data sets, the I²t load of the motors is monitored
based on the corresponding rated values. Once the set Warning Limit
I2t 615 is reached, a warning “A0200” will be triggered. Once the
fixed error threshold of 100%
Motor
(120%
Stator
) is exceeded, there will
be an error shutdown “F0401”. Both events will be triggered by the
active data set.
I²t,Single-Motor
Op.,Warning and
Err.Sw.-Off
The I²t load of the motor is monitored via the rated values from the
active data SE. Once the set Warning Limit I2t 615 is reached, a
warning “A0200” will be triggered. Once the fixed error threshold of
100%
Motor
(120%
Stator
) is exceeded, there will be an error shutdown
“F0401”. Both events will be triggered by the active data set.
The thermal time constant for the motor is in the range between a couple of minutes and several
hours. This motor-specific parameter is set via Thermal time constant motor 608.
The thermal time constant of the stator is much smaller. To protect the stator winding, additional
monitoring is required and defined via the Thermal time constant stator 609. For the time constant
values, refer to the relevant motor datasheets. If time constants are estimated, optimum motor
protection cannot be guaranteed.