Danfoss VLT AQUA Drive FC 202 Programming Manual page 51

Parameter Description
1-72 Start Function
Option: Function:
[2] coast
[0] DC-hold
[1] PM non-salient:
[2] coast
1-73 Flying Start
Option: Function:
This function makes it possible to catch a motor
which is spinning freely due to a mains drop-out.
When parameter 1-73 Flying Start is enabled,
parameter 1-71 Start Delay has no function.
Search direction for flying start is linked to the
setting in 4-10 Motor Speed Direction.
[0] Clockwise: Flying start search in clockwise
direction. If not successful, a DC brake is carried
out.
[2] Both Directions: The flying start first makes a
search in the direction determined by the last
reference (direction). If not finding the speed it
makes a search in the other direction. If not
successful, a DC brake is activated in the time set
in parameter 2-02 DC Braking Time. Start then takes
place from 0 Hz.
[0] Disabled Select [0] Disable if this function is not required
[1] Enabled Select [1] Enable to enable the frequency converter
to "catch" and control a spinning motor.
The parameter is always set to [1] Enable when
parameter 1-10 Motor Construction = [1] PM non-
salient.
Important related parameters:
•
1-58 Flystart Test Pulses Current
•
1-59 Flystart Test Pulses Frequency
•
Parameter 1-70 PM Start Mode
•
Parameter 2-06 Parking Current
•
Parameter 2-07 Parking Time
•
Parameter 2-03 DC Brake Cut In Speed
[RPM]
•
2-04 DC Brake Cut In Speed [Hz]
•
Parameter 2-06 Parking Current
•
Parameter 2-07 Parking Time
When parameter 1-73 Flying Start is enabled,
parameter 1-71 Start Delay has no function.
Search direction for flying start is linked to the setting in
4-10 Motor Speed Direction.
[0] Clockwise: Flying start search in clockwise direction. If
not successful, a DC brake is carried out.
MG20O702
Programming Guide
[2] Both Directions: The flying start first makes a search in
the direction determined by the last reference (direction). If
not finding the speed it makes a search in the other
direction. If not successful, a DC brake is activated in the
time set in parameter 2-02 DC Braking Time. Start then
takes place from 0 Hz.
The flying start function used for PM motors is based on
an initial speed estimation. The speed is always estimated
as the first thing after an active start signal is given. Based
on the setting of parameter 1-70 PM Start Mode the
following happens:
Parameter 1-70 PM Start Mode = [0] Rotor Detection:
If the speed estimate comes out as greater than 0 Hz the
frequency converter catches the motor at that speed and
resume normal operation. Otherwise, the frequency
converter estimates the rotor position and start normal
operation from there.
Parameter 1-70 PM Start Mode = [1] Parking:
If the speed estimate comes out lower than the setting in
1-59 Flystart Test Pulses Frequency then 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. Refer to description of
parameter 1-70 PM Start Mode for recommended settings.
Current limitations of the flying start principle used for PM
motors:
•
•
•
•
•
•
1-79 Pump Start Max Time to Trip
Range:
0 s [0 - 10
*
s]
Danfoss A/S © Rev. 2014-01-21 All rights reserved.
The speed range is up to 100% Nominal Speed or
the field weakening speed (which ever is lowest).
PMSM with high back EMF (>300 VLL(rms)) and
high-winding inductance (>10 mH) needed more
time for reducing short circuit current to zero and
may be susceptible to error in estimation.
Current testing limited to a speed range up to
300 Hz. For certain units the limit is 250 Hz; all
200-240 V units up to and including 2.2 kW and
all 380-480 V units up to and including 4 kW.
Current testing limited to a machine power size
up to 22 kW.
Prepared for salient pole machine (IPMSM) but
not yet verified on those types of machine.
For high-inertia applications (i.e. where the load
inertia is more than 30 times larger than the
motor inertia) a brake resistor is recomended to
avoid over-voltage trip during high speed
engagement of the flying start function.
Function:
If the motor does not reach the speed specified in
1-86 Trip Speed Low [RPM] within the time
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