Flying Start / Ride-Through - WEG CFW100 Programming Manual

Description:
It defines the point at which automatic gradual reduction of the switching frequency occurs. That significantly
improves the measurement of the output current at low frequencies and consequently the performance of the
inverter.
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NOTE!
Both the function related to P219 and the function controlled by P397 (bit 3) act by reducing the
switching frequency. As the function related to P219 is intended to improve the reading of the inverter
current, that function has priority of action over the function controlled by P397 (bit 3).
P297 - Switching Frequency
Range: 2.5 to 15.0 kHz
Properties: cfg, V/f, VVW
Description:
You can use this parameter to define the inverter IGBT switching frequency.
The inverter switching frequency may be adjusted according to the application needs. Higher switching frequencies
imply less acoustic noise in the motor. However, the switching frequency choice results in a compromise among
the acoustic noise in the motor, the inverter IGBT losses and the maximum permitted currents.
The reduction of the switching frequency reduces the effects related to the motor instability, which occurs in certain
application conditions. Besides, it reduces the earth leakage current, preventing the actuation of the faults F070
(output overcurrent or short-circuit).

8.1.3 Flying Start / Ride-Through

The Flying Start function allows driving a motor that is in free running, accelerating it from the rotation in which it is.
The Ride-Through function allows recovering the inverter, with no locking by undervoltage, when there is an instant
drop in the power supply.
Both functions assume the special case in which the motor is running in the same direction and at a frequency close
to the frequency reference, thus, by immediately applying the frequency reference to the output and increasing the
output voltage in ramp, the slip and the starting torque are minimized.
P320 - Flying Start / Ride-Through
Range: 0 = Inactive
1 = Flying Start
2 = FS / RT
3 = Ride-Through
Properties: cfg
Description:
Parameter P320 selects the use of the Flying Start and Ride-Through functions.
Flying Start Function (FS): In order to activate this function, just program P320 in 1 or 2; thus the inverter will
impose a fixed frequency at the start, defined by the frequency reference, and apply the voltage ramp defined in
parameter P331. In this way, the start current is reduced. On the other hand, if the motor is at rest, the frequency
reference and the real frequency of the motor are very different or the direction of rotation is inverted; the result in
such cases may be worse than the conventional start without Flying Start.
The Flying Start function is applied on loads with high inertia or systems that require start with the motor spinning.
Besides, the function may be deactivated dynamically by a digital input P263 to P266 programmed for "24
= Disable Flying Start". In this way, the user may activate the function in a convenient way according to the
MOTOR CONTROL
Micro Mini Drives | 8-9
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