1-66 Min. Current at Low Speed
Range: Function:
50 %* [0 - 120 %] Applies to PM motors only. Increasing the
minimum current improves motor torque at
low speed, but also reduces eciency.
3.2.9 1-7* Start Adjustments
Parameters for conguring special motor start features.
1-70 Start Mode
This parameter is valid since software version 2.80 and later
versions. Use this parameter to select the PM motor start mode
which is to initialize the VVC
+
control core for previously free-
running PM motors. This parameter is active for PM motors in
VVC
+
mode only if the motor is stopped (or running at low
speed).
Option: Function:
[0] Rotor Detection The rotor detection function estimates the
electrical angle of the rotor and uses the
angle as a starting point. This option is
the standard selection for automation
frequency converter applications. If the
ying start function detects that motor is
running at low speed or is stopped, the
frequency converter can detect the rotor
position (the angle). The frequency
converter then starts the motor from that
angle.
[1] * Parking The parking function applies DC current
across the stator winding and rotates the
rotor to electrical zero position. This
function is typically selected for HVAC
applications. If the ying start function
detects that motor is running at low
speed or is stopped, the frequency
converter sends out a DC current to park
the motor at an angle. The frequency
converter then starts the motor from that
angle.
1-71 Start Delay
Range: Function:
0 s* [0 - 10
s]
This parameter enables a delay of the starting
time. The frequency converter begins with the
start function selected in parameter 1-72 Start
Function. Set the start delay time until
acceleration is to begin.
1-72 Start Function
Option: Function:
[0] DC Hold/
delay time
The motor is energized with
parameter 2-00 DC Hold/Motor Preheat Current
during start delay time.
[2] * Coast/delay
time
The frequency converterA temperature-
dependent resistor is coasted during start
delay time (frequency converter o).
1-73 Flying Start
This function makes it possible to catch a motor that is spinning
freely due to a mains drop-out. Flying start searches in clockwise
direction only. If not successful, a DC brake is activated. If PM-
enabled options are selected, parking is carried out if the speed
is below 2.5–5% of nominal speed, in the time set in
parameter 2-07 Parking Time.
If the speed estimate comes out below 2.5–5% of nominal speed,
the parking function is engaged (see parameter 2-06 Parking
Current and parameter 2-07 Parking Time). Otherwise, the
frequency converter catches the motor at that speed and
resumes normal operation.
The ying start function used for PM motors is based on an
initial speed estimation. The speed is always estimated as the
rst thing after an active start signal is given.
Current limitations of the ying start principle used for PM
motors:
•
The speed range is up to 100% nominal speed or the
eld weakening speed (whichever is lowest).
•
For high inertia applications (that is, where the load
inertia is more than 30 times larger than the motor
inertia).
Option: Function:
[0] Disabled
[1] Enabled
3.2.10 1-8* Stop Adjustments
Parameters for conguring special motor stop features.
1-80 Function at Stop
Option: Function:
Select this 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].
[0] * Coast Leaves the motor in free mode.
[1] DC hold /
Motor
Preheat
Energizes the motor with a DC hold current
(see parameter 2-00 DC Hold/Motor Preheat
Current).
Parameters Programming Guide
MG18B502 Danfoss A/S © 04/2018 All rights reserved. 37
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