Danfoss VLT Midi Drive FC 280 Programming Manual page 40

Parameter Descriptions
1-76 Start Current
Range:
4 4
1-78 Compressor Start Max Speed [Hz]
Range:
0 Hz [ 0 -
*
500 Hz]
1-79 Compressor Start Max Time to Trip
Range:
5 s [0 -
*
10 s]
1-80 Function at Stop
Option:
38
Function:
set the required current in this parameter.
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.
Function:
This parameter enables high starting torque. The
time from the start signal is given until the
speed exceeds the speed set in this parameter
becomes a start zone. In the start zone, the
current limit and motoric torque limit are set to
the maximum possible value for the frequency
converter/motor combination. The time without
protection from the current limit and torque
limit must not exceed the value set in
parameter 1-79 Compressor Start Max Time to Trip.
Otherwise, the frequency converter trips with
alarm 18, Start Failed.
Function:
The time from the start signal is given until the
speed exceeds the speed set in
parameter 1-78 Compressor Start Max Speed [Hz]
must not exceed the time set in this parameter.
Otherwise, the frequency converter trips with alarm
18, Start Failed. Any time set in parameter 1-71 Start
Delay for use of a start function must be executed
within the time limit.
Function:
Select the frequency converter function after
a stop command or after the speed is ramped
down to the settings in parameter 1-82 Min
Speed for Function at Stop [Hz].
Available selections depend on the setting in
parameter 1-10 Motor Construction.
•
[0] Asynchron.
-
[0] Coast.
- [1] DC hold.
-
[3] Pre-magnetizing.
•
[1] PM, non-salient SPM, non Sat.
•
[2] PM, salient IPM, non Sat.
•
[3] PM, salient IPM, Sat.
- [0] Coast.
- [1] DC hold.
Danfoss A/S © 07/2016 All rights reserved.
®
VLT Midi Drive FC 280
1-80 Function at Stop
Option:
[0] Coast
*
[1] DC hold /
Motor
Preheat
[3] Pre-
magnetizing
1-82 Min Speed for Function at Stop [Hz]
Range:
0 Hz
*
1-83 Precise Stop Function
Option:
[0] Precise ramp
stop
*
[1] Counter stop
with reset
Function:
Leave the motor in free mode.
Energize the motor with a DC hold current
(see parameter 2-00 DC Hold/Motor Preheat
Current.
Build up a magnetic field while the motor is
stopped. This allows the motor to produce
torque quickly at commands (asynchronous
motors only). This premagnetizing function
does not help the very first start command.
Two different solutions are available to pre-
magnetize the machine for the first start
command:
1. Start the frequency converter with a
0 RPM reference and wait 2–4 rotor
time constants (see the equation
below) before increasing the speed
reference.
2. 2a Set parameter 1-71 Start
Delay to the premagnetize
time (2–4 rotor time
constants).
2b Set parameter 1-72 Start
Function to [0] DC hold.
2c Set the DC-hold current
magnitude
(parameter 2-00 DC Hold/
Motor Preheat Current to be
equal to I
(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
Function:
[0 - 20 Hz] Set the output frequency at which to
activate parameter 1-80 Function at Stop.
Function:
Only optimal when the operational speed
(for example the operational speed of a
conveyor belt) is constant. This is an open-
loop control. Achieves high repetitive
precision at the stopping point.
Count the number of pulses, typically from
an encoder, and generates a stop signal
after a preprogrammed number of pulses
= U /
pre-mag nom
MG07C302