Danfoss VLT Refrigeration Drive FC 103 Programming Manual page 49

Parameter Description
1-72 Start Function
Option: Function:
[2] Coast
[0] DC-hold
[1] PM non-salient:
[2] coast
[3] Start speed
cw
[5] VVC+/Flux
clockwise
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:
•
Parameter 1-58 Flying Start Test Pulses
Current
•
Parameter 1-59 Flying Start 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]
•
Parameter 2-04 DC Brake Cut In Speed [Hz]
•
Parameter 2-06 Parking Current
•
Parameter 2-07 Parking Time
[2] Enabled
Always
[3] Enabled
Ref. Dir.
MG16H202
Programming Guide
1-73 Flying Start
Option:
[4] Enab.
Always
Ref. Dir.
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 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 PM 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 PM Start Mode for recommended settings.
Current limitations of the flying-start principle used for PM
motors:
•
•
•
•
1-74 Start Speed [RPM]
Range:
Size
related
*
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Function:
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
time for reducing short-circuit current to 0 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
(3 hp) and all 380–480 V units up to and
including 4 kW (5 hp).
For high-inertia applications (that is, where the
load inertia is more than 30 times larger than the
motor inertia), use a brake resistor to avoid
overvoltage trip during high-speed engagement
of the flying-start function.
Function:
[0 - Set a motor start speed. After the start
600 signal, the output speed leaps to set value.
RPM] Set the start function in
parameter 1-72 Start Function to [3] Start
speed cw, [4] Horizontal operation, or [5] VVC
+
/Flux clockwise, and set a start delay time
in parameter 1-71 Start Delay.
3 3
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