Dc Braking - Danfoss VLT FCD 303 Operating Instructions Manual

Choose Start frequency/voltage clockwise [3] to
obtain the function described in parameter 130
Start frequency and 131 Voltage at start during start
delay time. Regardless of the value assumed by
the reference signal, the output frequency equals
the setting in parameter 130 Start frequency and
the output voltage will correspond to the setting
in parameter 131 Voltage at start .
This functionality is typically used in hoist applications.
It is used in particular in applications in which a cone
anchor motor is applied, where the direction of rotation
is to start clockwise followed by the reference direction.
Select Start frequency/voltage in reference direction
[4] to obtain the function described in parameter
130 Start frequency and 131 Voltage at start
during the start delay time.
The direction of rotation of the motor will always
follow in the reference direction. If the reference signal
equals zero, the output frequency will equal 0 Hz,
while the output voltage will correspond to the setting
in parameter 131 Voltage at start. If the reference
signal is different from zero, the output frequency will
equal parameter 130 Start frequency and the output
voltage will equal parameter 131 Voltage at start. This
functionality is used typically for hoist applications with
counterweight. It is used in particular for applications
in which a cone anchor motor is applied. The cone
anchor motor can break away using parameter 130
Start frequency and parameter 131 Voltage at start.
122 Function at stop
(FUNCTION AT STOP)
Value:
Coasting (COAST)
DC hold (DC HOLD)
Function:
This is where to choose the function of the frequency
converter after the output frequency has become
lower than the value in parameter 123 The min.
frequency for acti v ation of function at stop or after
a stop command and when the output frequency
has been ramped down to 0 Hz.
Description of choice:
Select Coasting [0] if the frequency converter is to
'let go' of the motor (inverter turned off).
Select DC hold [1] if parameter 137 DC hold
voltage is to be acti v ated.
= factory setting. () = display text [] = value for use in communication via serial communication port
MG.04.B7.02 - VLT is a registered Danfoss trademark
VLT
123 Min. frequency for activation of
function at stop
(MIN.F.FUNC.STOP)
Value:
0,1 - 10 Hz
Function:
In this parameter, the output frequency is set at
which the function selected in parameter 122
Function at stop is to be acti v ated.
Description of choice:
Set the required output frequency.
NB!:
If parameter 123 is set higher than parameter
130, then the start delay function (parameter
120 and 121) will be skipped.
NB!:
If parameter 123 is set too high, and DC
hold has been chosen in parameter 122,
the output frequency will jump to the value
in parameter 123 without ramping up. This may
cause an overcurrent warning / alarm.

DC Braking

During DC braking DC voltage is supplied to the
motor, and this will cause the shaft to be brought to
a standstill. In parameter 132 DC brake voltage DC
brake voltage can be preset from 0-100%. Max. DC
brake voltage depends on the motor data selected.
In parameter 126 DC braking time DC braking time
is determined and in parameter 127 DC brake cut-in
frequency the frequency at which DC braking becomes
acti v e is selected. If a digital input is programmed to DC
[0]
braking inverse [5] and shifts from logic '1' to logic '0',
[1]
DC braking will be acti v ated. When a stop command
becomes acti v e, DC braking is acti v ated when the
output frequency is less than the brake cut-in frequency.
NB!:
DC braking may not be used if the inertia in
the motor shaft is more than 20 times greater
than the motor's internal inertia.
®
FCD Series
0,1 Hz
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