Danfoss VLT FC 102 Programming Manual page 65

Parameter Descriptions
1-72 Start Function
Option: Function:
[0] DC Hold/ Energizes the motor with a DC
Motor Preheat holding current (parameter 2-00 DC
Hold/Preheat Current) during the
start delay time.
[2] Coast Releases the shaft-coasted
frequency converter during the
start delay time (inverter off).
Available selections depend on
parameter 1-10 Motor Construction:
[0] Asynchron:
[1] PM non-salient:
1-73 Flying Start
Option: Function:
This function enables catching 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
parameter 4-10 Motor Speed
Direction.
[0] Clockwise: Flying start searches
in clockwise direction. If not
successful, a DC brake is activated.
[2] Both Directions: The flying start
first makes a search in the direction
determined by the last reference
(direction). If the speed is not
found, 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:
M0010001
Programming Guide
[2] Coast
[0] DC-hold
[2] coast
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1-73 Flying Start
Option: Function:
[2] Enabled Enable at every start.
Always
[3] Enabled Ref. Enable after coast, search in
Dir. reference direction only.
[4] Enab. Always Enable at every start, search in
Ref. Dir. reference direction only.
The flying-start function used for PM motors is based on
an initial speed estimation. The speed is always estimated
st
as the 1 thing after an active start signal is given. Based
on the setting of parameter 1-70 Start Mode the following
happens:
Parameter 1-70 Start Mode=[0] Rotor Detection:
If the speed estimate appears as greater than 0 Hz, the
frequency converter catches the motor at that speed and
resumes normal operation. Otherwise, the frequency
converter estimates the rotor position and start normal
operation from there.
Parameter 1-70 Start Mode=[1] Parking:
A speed estimate lower than the setting in
parameter 1-59 Flying Start Test Pulses Frequency engages
the parking function (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 the description of
parameter 1-70 Start Mode for recommended settings.
Current limitations of the flying-start principle used for PM
motors:
•
The speed range is up to 100% nominal speed or
the field weakening speed (whichever is lowest).
•
PMSM with high back EMF (>300 VLL(rms)) and
high winding inductance (>10 mH) needs more
•
Parameter 1-58 Flying Start
Test Pulses Current
•
Parameter 1-59 Flying Start
Test Pulses Frequency
•
Parameter 1-70 Start Mode
•
Parameter 2-06 Parking
Current
•
Parameter 2-07 Parking
Time
•
Parameter 2-03 DC Brake
Cut In Speed [RPM]
•
Parameter 2-04 DC Brake
Cut In Speed [Hz]
•
Parameter 2-06 Parking
Current
•
Parameter 2-07 Parking
Time
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