Danfoss VLT 2800 Design Manual page 73

Programming
Speed to go from nominal to 0 flux level: 500ms
Description of functionality:
The filter monitors the active motor current and changes
the motor voltage according to Illustration 4.3. The filter
reacts on levels referring to the nominal motor current.
Illustration 4.3 Resonance Damping
If the active motor current is below 10%, the motor
voltage is decreased by the speed mentioned above until
the voltage reaches the setting for Parameter 117
Resonance damping. If the active motor current exceeds
20%, the voltage is increased by the above mentioned
speed. If the active motor current reaches 40%, the motor
voltage is increased immediately to normal motor voltage.
The reduction in motor voltage depends on the parameter
117 Resonance damping setting.
Description of choice:
Set the grade of motor current [I
ratio between 0% (OFF) and 100%. 100% corresponds to
50% reduction of U/F ratio. Default value is OFF.
119 High start torque
Value:
0.0 - 0.5 s
Function:
To ensure a high start torque approx. 1.8 x I
permitted for max. 0.5 s. The current is, however, limited
by the frequency converter's (inverter's) safety limit. 0 s
corresponds to no high start torque.
Description of choice:
Set the necessary time for which a high start torque is
required.
MG27E402
Design Guide
] influence on the U/F
mact
0.0 s
can be
INV.
Danfoss A/S © Rev. May/2014 All rights reserved.
120 Start delay
Value:
0.0 - 10.0 s
Function:
This parameter enables a delay of the start-up time after
the conditions for start have been fulfilled. When the time
has passed, the output frequency starts by ramping up to
the reference.
Description of choice:
Set the necessary time before commencing to accelerate.
121 Start function
Value:
DC hold during start delay time
(DC HOLD/DELAY TIME)
DC brake during start delay time
(DC BRAKE/DELAY TIME)
Coasting during start delay time
(COAST/DELAY TIME)
Start frequency/voltage clockwise
(CLOCKWISE OPERATION)
Start frequency/voltage in reference direction
(VERTICAL OPERATION)
Function:
Select the required mode during the start delay time
(parameter 120 Start delay time).
Description of choice:
Select [0] DC hold during start delay time to energise the
motor with a DC hold voltage during the start delay time.
Set voltage in parameter 137 DC hold voltage.
Select [1] DC brake during start delay time to energise the
motor with a DC brake voltage during the start delay time.
Set voltage in parameter 132 DC brake voltage.
Select [2] Coasting during start delay time and the motor is
not controlled by the adjustable frequency drive during
the start delay time (inverter turned off).
Select [3] Start frequency/voltage clockwise to obtain the
function described in parameters 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 corresponds to the
setting in parameter 131 Voltage at start.
This functionality is typically used in hoist applications. It is
particularly used 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 [4] Start frequency/voltage in reference direction to
obtain the function described in parameters 130 Start
frequency and 131 Voltage at start during the start delay
time.
The direction of rotation of the motor always follows in
the reference direction. If the reference signal equals 0, the
output frequency equals 0 Hz, while the output voltage
corresponds to the setting in parameter 131 Voltage at
start. If the reference signal is different from zero, the
0.0 s
4 4
[0]
[1]
[2]
[3]
[4]
71