Danfoss VLT AutomationDrive FC 301 Programming Manual page 72

Parameter Descriptions
1-76 Start Current
Range:
0 A
*
A]
3 3
3.2.11 1-8* Stop Adjustments
1-80 Function at Stop
Option:
[0] Coast
*
[1] DC hold
[2] Motor check
[3] Pre-
magnetizing
70
Function:
[ 0 - par. 1-24 Some motors, for example cone
rotor motors, need extra current/
starting speed to disengage the
rotor. To obtain this boost, set the
required current in
parameter 1-76 Start Current. Set
parameter 1-74 Start Speed [RPM].
Set parameter 1-72 Start Function to
[3] Start speed cw or [4] Horizontal
operation, and set a start delay time
in parameter 1-71 Start Delay.
This parameter can be used for
hoist applications (cone rotor).
Function:
Select the frequency converter
function after a stop command or
after the speed is ramped down to
the settings in parameter 1-81 Min
Speed for Function at Stop [RPM].
Leaves motor in free mode. The
motor is disconnected from the
frequency converter.
Energizes the motor with a DC hold
current (see parameter 2-00 DC Hold
Current).
Checks if a motor has been
connected. The interval for
checking the motor can be defined
in parameter 4-49 Motor Check Time
Interval.
Builds up a magnetic field while the
motor is stopped. This allows the
motor to produce torque quickly at
subsequent start commands
(asynchronous motors only). This
premagnetizing function does not
help the very 1 st start command.
Two different solutions are available
to premagnetize the machine for
the 1 st start command:
•
Start the frequency
converter with a 0 RPM
reference and wait 2-4
rotor time constants
Danfoss A/S © 10/2019 All rights reserved.
®
VLT AutomationDrive FC 301/302
1-80 Function at Stop
Option:
[4]
[5]
[6]
[8]
1-81 Min Speed for Function at Stop [RPM]
Range:
Size
related
*
1-82 Min Speed for Function at Stop [Hz]
Range:
Size
related
*
Function:
before increasing the
speed reference.
•
Use the start delay with
DC hold:
Set parameter 1-71 Start Delay to
the required premagnetizing time
(2–4 rotor time constants. See the
time constants description further
in this section.
Set parameter 1-72 Start Function to
either [0] DC hold or [1] DC Brake
Set the DC hold or DC brake
current magnitude
(parameter 2-00 DC Hold Current or
parameter 2-01 DC Brake Current) to
be equal to I_pre-mag = Unom/
(1.73 x Xh)
Sample rotor time constants =
(Xh+X2)/(6.3*Freq_nom*Rr)
1 kW = 0.2 s
10 kW = 0.5 s
100 kW = 1.7 s
1000 kW = 2.5 s
DC Voltage U0 When the motor is stopped, the
parameter 1-55 U/f Characteristic - U
[0] defines the voltage at 0 Hz.
Coast at low When the reference is below
reference parameter 1-81 Min Speed for
Function at Stop [RPM], the motor is
disconnected from the frequency
converter.
Motor check,
alarm
Torque ramp
to zero
Function:
[0 - 600 Set the speed at which to activate
RPM] parameter 1-80 Function at Stop.
Function:
[ 0 - 500.0 Set the output frequency at which
Hz] to activate parameter 1-80 Function
at Stop.
M0013101