GE AF-650 GP Programming Manual page 88

Parameter Descriptions
3.9.1 SP-1# Line On/Off
Parameters to configure actions taken for Line Failures,
Input Fault, and Imbalance.
SP-10 Line failure
Options [1] Ctrl. ramp-down, [2] Ctrl. ramp-down, trip, [5] Kinetic
back-up, trip, [7] Kin. back-up, trip w recovery are not active when
the option [2] Torque is selected in parameter H-40 Configuration
Mode.
Option: Function:
NOTICE
Parameter SP-10 Line failure cannot be
changed while motor runs.
Parameter SP-10 Line failure is typically used
where very short mains interruptions (voltage
dips) are present. At 100% load and a short
voltage interruption, the DC voltage on the main
capacitors drops quickly. For larger frequency
converters, it only takes a few milliseconds
before the DC level drops to about 373 V DC,
and the IGBTs cut off and lose the control of the
motor. When mains is restored, and the IGBTs
start again, the output frequency and voltage
vector do not correspond to the speed/
frequency of the motor, and the result is
normally an overvoltage or overcurrent, mostly
resulting in a trip lock. Parameter SP-10 Line
failure can be programmed to avoid this
situation.
Select the function according to which the
frequency converter must act when the
threshold in parameter SP-11 Line Voltage at Input
Fault is reached.
[0] No The frequency converter does not compensate
function for a mains interruption. The voltage on the DC
*
link drops quickly and motor control is lost
within milliseconds to seconds. Trip lock is the
result.
[1] Ctrl. Control of the motor remains with the frequency
Decel converter, and the frequency converter performs
a controlled ramp down from
parameter SP-11 Line Voltage at Input Fault level.
If parameter B-10 Brake Function is [0] Off or [2]
AC brake, the ramp follows the overvoltage
ramping. If parameter B-10 Brake Function is [1]
Resistor Brake, the ramp follows the setting in
parameter C-23 Quick Stop Decel Time. This
selection is useful in pump applications, where
the inertia is low and the friction is high. When
mains is restored, the output frequency ramps
the motor up to the reference speed (if the
mains interruption is prolonged, the controlled
ramp down may bring the output frequency
DET-618D
AF-650 GP™ Programming Guide
SP-10 Line failure
Options [1] Ctrl. ramp-down, [2] Ctrl. ramp-down, trip, [5] Kinetic
back-up, trip, [7] Kin. back-up, trip w recovery are not active when
the option [2] Torque is selected in parameter H-40 Configuration
Mode.
Option:
[2] Ctrl.
Decel,
trip
[3] Coasting
[4] Kinetic
back-up
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Function:
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). If the energy in the DC link disappears
before the motor is ramped to 0, the motor is
coasted.
Limitation:
See the introduction text in parameter SP-10 Line
failure.
The functionality is the same as in option [1] Ctrl.
ramp-down, except in this option a reset is
necessary for starting up after power-up.
Centrifuges can run for 1 hour without 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.
Kinetic back-up ensures that the frequency
converter keeps running as long as there is
energy in the system due to the inertia from
motor and load. This is done by converting the
mechanical energy to the DC link and
maintaining control of the frequency converter
and motor. This can extend the controlled
operation, depending on the inertia in the
system. For fans, it is typically several seconds;
for pumps up to 2 seconds; and for compressors
only for a fraction of s. Many industry
applications can extend controlled operation for
many s, which is often enough time for the
mains to return.
A Normal operation
B Mains failure
C Kinetic back-up
D Mains return
E Normal operation: ramping
Illustration 3.37 Kinetic Back-up
The DC level during [4] Kinetic back-up equals to
parameter SP-11 Line Voltage at Input Fault * 1.35.
3 3
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