[0] * No function This selection does not present a danger to the frequency converter, but a trip lock would normally
be the result of the short voltage interruptions.
[1] Ctrl. ramp-down This selection will keep the output frequency following the motor speed. The IGBT will not loose
the connection to the motor, but will follow the speed down. This is particularly useful in pump
applications, where the inertia is low and the friction is high. When the mains is restored, the output
frequency will ramp the motor up to the reference speed (if the mains interruption is prolonged, the
controlled ramp down might take the output frequency all the way down to 0 rpm , and when the
mains is restored, the application is ramped up from 0 rpm to the previous reference speed via the
normal ramp up).
[2] Ctrl. ramp-down, trip
[3] Coasting Centrifuges can run for an hour without power supply. In those situations it is possible to select a
coast function at mains interruption, together with a flying start which occurs when the mains is
restored.
[4] Kinetic back-up Kinetic back up will maintain the DC level as long as possible, by converting the mechanical energy
from the motor to the DC level supply. Fans normally can extend the mains interruptions for several
seconds. Pumps can normally only extend the interruptions for 1-2 seconds or fractions of seconds.
Compressors only for fractions of seconds.
[5] Kinetic back-up, trip
[6] Alarm
14-11 Mains Voltage at Mains Fault
Range: Function:
Application
dependent*
[180 - 600 V] This parameter defines the threshold voltage at which the selected function in par. 14-10
Mains
Failure
should be activated. The detection level is at a faktor sqrt(2) of the value in 14-11.
NB!
Note for converting between VLT 5000 and FC 300:
Even though the setting of the Mains Voltage at Mains Fault be the same for VLT
5000 and FC 300, the detection level is different. Use the following formula to
obtain the same detection level as in VLT 5000: 14-11 (VLT 5000 level) = Value
used in VLT 5000 * 1,35/sqrt(2).
14-12 Function at Mains Imbalance
Operation under severe main imbalance conditions reduces the lifetime of the motor. Conditions are considered severe if the motor is operated
continuously near nominal load (e.g. a pump or fan running near full speed).
Option: Function:
[0] * Trip Trips the frequency converter
[1] Warning Issues a warning
[2] Disabled No action
FC 300 Programming Guide 3 Parameter descriptions
MG.33.M8.02 - VLT
®
is a registered Danfoss trademark
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